| 1. |
- Singh, B. P., et al.
(författare)
-
Experimental access to Transition Distribution Amplitudes with the PANDA experiment at FAIR
- 2015
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Ingår i: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 51:8
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Tidskriftsartikel (refereegranskat)abstract
- Baryon-to-meson Transition Distribution Amplitudes (TDAs) encoding valuable new information on hadron structure appear as building blocks in the collinear factorized description for several types of hard exclusive reactions. In this paper, we address the possibility of accessing nucleon-to-pion (pi N) TDAs from (p) over barp -> e(+)e(-)pi(0) reaction with the future PANDA detector at the FAIR facility. At high center-of-mass energy and high invariant mass squared of the lepton pair q(2), the amplitude of the signal channel (p) over barp -> e(+)e(-)pi(0) admits a QCD factorized description in terms of pi N TDAs and nucleon Distribution Amplitudes (DAs) in the forward aid backward kinematic regimes. Assuming the validity of this factorized description, we perform feasibility studies for measuring (p) over barp -> e(+)e(-)pi(0) with the PANDA detector. Detailed simulations on signal reconstruction efficiency as well as on rejection of the most severe background channel, i.e. (p) over barp -> pi(+)pi(-)pi(0) were performed for the center-of-mass energy squared s = 5 GeV2 and s = 10 GeV2, in the kinematic regions 3.0 < q(2) < 4.3 GeV2 and 5 < q(2) < 9 GeV2, respectively, with a neutral pion scattered in the forward or backward cone vertical bar cos theta(pi 0)vertical bar > 0.5 in the proton-antiproton center-of-mass frame. Results of the simulation show that the particle identification capabilities of the PANDA detector will allow to achieve a background rejection factor of 5 . 10(7) (1 . 10(7)) at low (high) q(2) for s = 5 GeV2, and of 1 . 10(8) (6 . 10(6)) at low (high) q(2) for s = 10 GeV2, while keeping the signal reconstruction efficiency at around 40%. At both energies, a clean lepton signal can be reconstructed with the expected statistics corresponding to 2 of integrated luminosity. The cross sections obtained from the simulations are used to show that a test of QCD collinear factorization can be done at the lowest order by measuring scaling laws and angular distributions. The future measurement of the signal channel cross section with PANDA will provide a new test of the perturbative QCD description of a novel class of hard exclusive reactions and will open the possibility of experimentally accessing pi N TDAs.
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| 2. |
- Collaboration, The PANDA, et al.
(författare)
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Feasibility studies of time-like proton electromagnetic form factors at PANDA at FAIR
- 2016
-
Ingår i: European Physical Journal A. - : Springer Publishing Company. - 1434-6001 .- 1434-601X. ; 52:10
-
Tidskriftsartikel (refereegranskat)abstract
- Simulation results for future measurements of electromagnetic proton form factors at P ¯ ANDA (FAIR) within the PandaRoot software framework are reported. The statistical precision with which the proton form factors can be determined is estimated. The signal channel p¯ p→ e+e- is studied on the basis of two different but consistent procedures. The suppression of the main background channel, i.e.p¯ p→ π+π-, is studied. Furthermore, the background versus signal efficiency, statistical and systematical uncertainties on the extracted proton form factors are evaluated using two different procedures. The results are consistent with those of a previous simulation study using an older, simplified framework. However, a slightly better precision is achieved in the PandaRoot study in a large range of momentum transfer, assuming the nominal beam conditions and detector performance.
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| 3. |
- Erni, W., et al.
(författare)
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Technical design report for the PANDA (AntiProton Annihilations at Darmstadt) Straw Tube Tracker
- 2013
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Ingår i: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 49:2
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Tidskriftsartikel (refereegranskat)abstract
- This document describes the technical layout and the expected performance of the Straw Tube Tracker (STT), the main tracking detector of the PANDA target spectrometer. The STT encloses a Micro-Vertex-Detector (MVD) for the inner tracking and is followed in beam direction by a set of GEM stations. The tasks of the STT are the measurement of the particle momentum from the reconstructed trajectory and the measurement of the specific energy loss for a particle identification. Dedicated simulations with full analysis studies of certain proton-antiproton reactions, identified as being benchmark tests for the whole PANDA scientific program, have been performed to test the STT layout and performance. The results are presented, and the time lines to construct the STT are described.
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| 4. |
- Singh, B., et al.
(författare)
-
Feasibility study for the measurement of pi N transition distribution amplitudes at (P)over-barANDA in (P)over-barp -> J/psi pi(0)
- 2017
-
Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 95:3
-
Tidskriftsartikel (refereegranskat)abstract
- The exclusive charmonium production process in (P) over barp annihilation with an associated pi 0 meson (p) over barp -> J/psi pi(0) is studied in the framework of QCD collinear factorization. The feasibility of measuring this reaction through the J/psi -> e(+) e(-) decay channel with the AntiProton ANnihilation at DArmstadt ((P) over bar ANDA) experiment is investigated. Simulations on signal reconstruction efficiency as well as the background rejection from various sources including the (P) over barp -> pi(+)pi(-)pi(0) and (p) over barp -> J/psi pi(0)pi(0) reactions are performed with PANDAROOT, the simulation and analysis software framework of the (P) over bar ANDA experiment. It is shown that the measurement can be done at (P) over bar ANDA with significant constraining power under the assumption of an integrated luminosity attainable in four to five months of data taking at the maximum design luminosity.
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| 5. |
- Singh, B., et al.
(författare)
-
Study of doubly strange systems using stored antiprotons
- 2016
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Ingår i: Nuclear Physics A. - : Elsevier. - 0375-9474 .- 1873-1554. ; 954, s. 323-340
-
Tidskriftsartikel (refereegranskat)abstract
- Bound nuclear systems with two units of strangeness are still poorly known despite their importance for many strong interaction phenomena. Stored antiprotons beams in the GeV range represent an unparalleled factory for various hyperon-antihyperon pairs. Their outstanding large production probability in antiproton collisions will open the floodgates for a series of new studies of systems which contain two or even more units of strangeness at the PANDA experiment at FAIR. For the first time, high resolution gamma-spectroscopy of doubly strange Lambda Lambda-hypernuclei will be performed, thus complementing measurements of ground state decays of Lambda Lambda-hypernuclei at J-PARC or possible decays of particle unstable hypernuclei in heavy ion reactions. High resolution spectroscopy of multistrange Xi(-) -atoms will be feasible and even the production of Omega(-) -atoms will be within reach. The latter might open the door to the vertical bar S vertical bar = 3 world in strangeness nuclear physics, by the study of the hadronic Omega(-) -nucleus interaction. For the first time it will be possible to study the behavior of Xi(+) in nuclear systems under well controlled conditions.
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| 6. |
- Artemov, A. N., et al.
(författare)
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Large effect of thermal processes on the susceptibility of YBCO film with transport current
- 2004
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Ingår i: Physica. C, Superconductivity. - : Elsevier BV. - 0921-4534 .- 1873-2143. ; 403:3, s. 157-162
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Tidskriftsartikel (refereegranskat)abstract
- The response of YBCO film with transport current to the weak alternating magnetic field was studied. The hysteresis of the temperature dependences of the response measured under cooling and heating was revealed. The qualitative explanation of this phenomenon is proposed. It is based on the fact that under certain conditions the superconductor with transport current has two steady states. It is found that the hysteresis arises only if transport current exceeds some finite value I-0.
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| 7. |
- Belotelov, V. I., et al.
(författare)
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Magnetophotonic intensity effects in hybrid metal-dielectric structures
- 2014
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 89:4, s. 045118-
-
Tidskriftsartikel (refereegranskat)abstract
- The magneto-optical properties of a hybrid metal-dielectric structure consisting of a one-dimensional gold grating on top of a magnetic waveguide layer are studied experimentally and theoretically. It is demonstrated that a magnetic field applied in the longitudinal configuration (in the plane of the magnetic film and perpendicular to the slits in the gold grating) to the metal-dielectric structure modifies the field distribution of the optical modes and thus changes the mode excitation conditions. In the optical far field, this manifests in the alteration of the optical transmittance or reflectance when the structure becomes magnetized. This magneto-optical effect is shown to represent a novel class of effects related to the magnetic-field-induced modification of the Bloch modes of the periodic hybrid structure. That is why we define this effect as "longitudinal magnetophotonic intensity effect" (LMPIE). The LMPIE has two contributions, odd and even in magnetization. While the even LMPIE is maximal for the light polarized perpendicular to the grating slits (TM) and minimal for the orthogonal polarization (TE), the odd LMPIE takes maximum values at some intermediate polarization and vanishes for pure TM and TE polarizations. Two principal modes of the magnetic layer - TM and TE - acquire in the longitudinal magnetic field additional field components and thus turn into quasi-TM and quasi-TE modes, respectively. The largest LMPIE is observed for excitation of the antisymmetrical quasi-TE mode by TM-polarized light. The value of the LMPIE measured for the plasmonic structure with a magnetic film of Bi2Dy1Fe4Ga1O12 composition is about 1% for the even effect and 2% for the odd one. However, the plasmonic structure with a magnetic film with a higher concentration of bismuth (Bi2.97Er0.03Fe4Al0.5Ga0.5O12) gives significantly larger LMPIE: even LMPIE reaches 24% and odd LMPIE is 9%. Enhancement of the magneto-optical figure of merit (defined as the ratio of the specific Faraday angle of a magnetic film to its absorption coefficient) of the magnetic films potentially causes the even LMPIE to exceed 100% as is predicted by calculations. Thus, the nanostructured material described here may be considered as an ultrafast magnetophotonic light valve.
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| 8. |
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| 9. |
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| 10. |
- Cheremisin, A. B., et al.
(författare)
-
Modification of Atomic Structure of Thin Amorphous V2O 5 Films under UV Laser Irradiation
- 2008
-
Ingår i: PROCEEDINGS OF THE 17TH INTERNATIONAL VACUUM CONGRESS/13TH INTERNATIONAL CONFERENCE ON SURFACE SCIENCE/INTERNATIONAL CONFERENCE ON NANOSCIENCE AND TECHNOLOGY. - : IOP Publishing.
-
Konferensbidrag (refereegranskat)abstract
- Influence of ultra-violet radiation of the KrF laser (wave length 248 nm, pulse duration 20 ns) on atomic structure of amorphous vanadium pentoxide thin films, prepared by the pulsed laser deposition method, is studied. Calculations of the short-range order characteristics (radii and diffusiveness of coordination spheres, coordination numbers) were performed by the Finbak -Warren method. It is established that minimal structure unit of amorphous V 2O5 film before and after irradiation is a strongly deformed oxygen octahedron. Distortions of tetragonal pyramids in the initial and modified film are different. Also, oxygen deficiency in a tetragonal pyramid is observed.
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| 11. |
- Putrolaynen, V. V., et al.
(författare)
-
Anti-Scratch AlMgB14 Gorilla (R) Glass Coating
- 2017
-
Ingår i: Technical physics letters. - : Maik Nauka/Interperiodica. - 1063-7850 .- 1090-6533. ; 43:10, s. 871-874
-
Tidskriftsartikel (refereegranskat)abstract
- Hard aluminum-magnesium boride (BAM) films were fabricated onto Corning (R) Gorilla (R) Glass by radio-frequency magnetron sputtering of a single stoichiometric AlMgB14 target. BAM films exhibit a Vickers hardness from 10 to 30 GPa and a Young's modulus from 80 to 160 GPa depending on applied loading forces. Deposited hard coating increases the critical load at which glass substrate cracks. The adhesion energy of BAM films on Gorilla (R) Glass is 6.4 J/m(2).
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| 12. |
- Sekirin, I. V., et al.
(författare)
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Determination of saturation magnetostriction of amorphous Fe-Co-P-B ribbons : Comparison of various methods
- 2019
-
Ingår i: VII Euro-Asian Symposium "Trends in Magnetism" 8–13 September 2019, Ekaterinburg, Russian Federation. - : Institute of Physics Publishing (IOPP).
-
Konferensbidrag (refereegranskat)abstract
- We present and compare results of measurement of saturation magnetostriction constants of amorphous ribbons Fe80-xCo x P14B6 (x = 23, 25, 28, 32, 40 at.%) and the reference Fe40Ni40P14B6 specimen employing Narita and Becker-Kersten methods. We also modified a strain gauge-based method to enable measurements of complete magnetic field dependence of magnetostriction coefficients.
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| 13. |
- Shkar, V. F., et al.
(författare)
-
A manifestation of magnetism of bismuth in iron garnet films
- 2003
-
Ingår i: Physics of the solid state. - : Pleiades Publishing Ltd. - 1063-7834 .- 1090-6460. ; 45:12, s. 2334-2337
-
Tidskriftsartikel (refereegranskat)abstract
- Bismuth iron garnet films prepared through electron-beam and laser-induced evaporation on (001)-oriented substrates of scandium gallium gadolinium garnet are investigated using ferromagnetic resonance. It is assumed that the additional minima observed in the angular dependence of the resonance field can be associated with the magnetic moment of bismuth ions.
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| 14. |
- Shkar, V. F., et al.
(författare)
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Structure and properties of deposited yttrium iron garnet films
- 2005
-
Ingår i: Physics of the solid state. - : Pleiades Publishing Ltd. - 1063-7834 .- 1090-6460. ; 47:6, s. 1107-1110
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Tidskriftsartikel (refereegranskat)abstract
- Ferromagnetic resonance (FMR) and vibrating-sample magnetometer techniques were used to study the nature of the structural characteristics of yttrium iron garnet films deposited through either liquid phase epitaxy or laser evaporation on a (111)-oriented gallium gadolinium garnet substrate. It was proved that, based on the experimentally observed cubic magnetic anisotropy, deposited films should be considered to be single crystals. However, the absence of the FMR domain branch in a nonsaturated film and the shape of the magnetization curve indicate that a deposited film when demagnetized does not have a domain structure, as would be expected for a single-crystal film. According to the model proposed, a deposited film consists of close-packed single-crystal fragments with equal crystallographic orientation, the boundaries between which are in a partially atomically disordered state. As a result, such a film is both locally and macroscopically anisotropic, like a continuous single crystal. This film can split into domains only within a fragment (as is the case in a magnetic granular polycrystal); however, this does not happen, because the linear dimensions of a submicroscopic fragment are smaller than the equilibrium domain width.
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| 15. |
- Tkatch, V. I., et al.
(författare)
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Estimation of the heat transfer coefficient in melt spinning process
- 2009
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Ingår i: Journal of Physics, Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 144, s. 012104-
-
Tidskriftsartikel (refereegranskat)abstract
- Effect of the quenching wheel velocity in the range 20.7-26.5 m/s on the cooling rate as well as on the structure and microtopology of the contact surfaces of the glass-forming FeNiPB melt-spun ribbons has been experimentally studied. Both the values of the cooling rate and heat transfer coefficient at the wheel-ribbon interface estimated from the temperature vs. time curves recorded during melt spinning runs are in the ranges (1.6-5.2)×10 6 K/s and (2.8-5.2)×10 5 Wm -2K -1, respectively, for ribbon thicknesses of 31.4-22.0 μm. It was found that the density of the air pockets at the underside surface of ribbons decreases while its average depth remains essentially unchanged with the wheel velocity. Using the surface quality parameters the values of the heat transfer coefficient in the areas of direct ribbon-wheel contact were evaluated to be ranging from 5.75 to 6.65×10 5 Wm -2K -1.
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| 16. |
- Belotelov, V. I., et al.
(författare)
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Plasmon-mediated magneto-optical transparency
- 2013
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 4, s. 2128-
-
Tidskriftsartikel (refereegranskat)abstract
- Magnetic field control of light is among the most intriguing methods for modulation of light intensity and polarization on sub-nanosecond timescales. The implementation in nanostructured hybrid materials provides a remarkable increase of magneto-optical effects. However, so far only the enhancement of already known effects has been demonstrated in such materials. Here we postulate a novel magneto-optical phenomenon that originates solely from suitably designed nanostructured metal-dielectric material, the so-called magneto-plasmonic crystal. In this material, an incident light excites coupled plasmonic oscillations and a waveguide mode. An in-plane magnetic field allows excitation of an orthogonally polarized waveguide mode that modifies optical spectrum of the magneto-plasmonic crystal and increases its transparency. The experimentally achieved light intensity modulation reaches 24%. As the effect can potentially exceed 100%, it may have great importance for applied nanophotonics. Further, the effect allows manipulating and exciting waveguide modes by a magnetic field and light of proper polarization.
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| 17. |
- Dzibrou, Dzmitry, et al.
(författare)
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Tailoring optical properties of pulsed laser deposited TiO2 films
- 2008
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Ingår i: PROCEEDINGS OF THE 17TH INTERNATIONAL VACUUM CONGRESS/13TH INTERNATIONAL CONFERENCE ON SURFACE SCIENCE/INTERNATIONAL CONFERENCE ON NANOSCIENCE AND TECHNOLOGY. - BRISTOL, ENGLAND : IOP PUBLISHING LTD. ; , s. 082035-
-
Konferensbidrag (refereegranskat)abstract
- The paper is dedicated to the investigation into optical properties of TiO2 thin films pulsed laser deposited at the temperature as low as 150 degrees C and subjected to the following heat treatment. Properties of obtained nanocrystalline films were compared to polycrystalline TiO2 films grown at elevated temperatures. The highest transmission and the best morphology in polycrystalline films have been obtained at the growth temperature of 300 degrees C. The two methods of post-annealing of amorphous films were employed: annealing at thermodynamically equilibrium conditions and rapid thermal annealing (RTA). RTA at 500 degrees C enables achievement of the best optical performance: smooth surface and high films transparency.
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| 18. |
- Grishin, Alexander M., et al.
(författare)
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Crystallization kinetics and magnetostriction properties of amorphous Fe 80-x Co x P 14 B 6 metallic glasses
- 2020
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Ingår i: Journal of Magnetism and Magnetic Materials. - : Elsevier. - 0304-8853 .- 1873-4766. ; 512
-
Tidskriftsartikel (refereegranskat)abstract
- Formation mechanism and crystallization kinetics were studied in series of rapidly solidified metallic glasses Fe80- xCoxP14B6 with x = 23, 25, 28, 32, 35 and 40 at.%. As soft magnetic materials, they surpass characteristics of commercial Iron-Nickel Metglas® 2826 alloy: differential permeability of as quenched amorphous ribbons is of about 110,000, the saturation induction μoMs = 1.45–1.5 T, coercive field as low as 4 A/m, Curie temperature above 700 K, and significantly higher thermal stability. Isochronal and isothermal differential scanning calorimetry was employed to record the latent heat developed during crystallization. For both regimes, X-ray diffraction revealed two immiscible bcc α-FeCo and bct (Fe,Co)3(P,B) phases that crystallize from completely miscible amorphous glass matrix. Theoretical description of observed kinetics of crystallization process was convincingly accomplished within Kolmogorov-Johnson-Mehl-Avrami model. Enhanced thermal stability of iron-rich Fe80- xCoxP14B6 glasses that crystalize at higher temperatures relies upon higher crystal/glass interfacial energy.
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| 19. |
- Grishin, Alexander M., et al.
(författare)
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Strong broad C-band room-temperature photoluminescence in amorphous Er2O3 film
- 2006
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 89:2
-
Tidskriftsartikel (refereegranskat)abstract
- Photoluminescence with the bandwidth of 45 nm (1523-1568 nm at the level of 3 dB) was observed in amorphous Er2O3 films grown on quartz substrate by pulsed laser ablation of erbium oxide stoichiometric target. Optical transmission spectrum has been fitted to Swanepoel formula [J. Phys. E 16, 1214 (1983)] to determine dispersion of refractive index and to extract resonance absorption peaks at 980 and 1535 nm. The maximum gain coefficient as high as 800 dB/cm at 1535 nm was estimated using McCumber theory and experimental spectrum of the resonance absorption. For 5 mm long waveguide amplifier with erbium doping confinement factor of 0.1, the theory predicts the spectral gain of 18 dB with 1.2 dB peak-to-peak flatness in the bandwidth of 31 nm (1532-1563 nm) when 73% of Er3+ ions are excited from the ground state to the I-4(3/2) laser level. Strong broadband photoluminescence at room temperature and inherently flat spectral gain promise Er2O3 films for ultrashort high-gain optical waveguide amplifiers and integrated light circuits.
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| 20. |
- Grishin, Alexander M., et al.
(författare)
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Ultra-hard amorphous AlMgB14 films RF sputtered onto curved substrates
- 2017
-
Ingår i: Materials Research Express. - : Institute of Physics (IOP). - 2053-1591. ; 4:3
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Tidskriftsartikel (refereegranskat)abstract
- Recently, hard AlMgB14 (BAM) coatings were deposited for the first time by RF magnetron sputtering using a single stoichiometric ceramic target. High target sputtering power and sufficiently short target-to-substrate distance were found to be critical processing conditions. They enabled fabrication of stoichiometric in-depth compositionally homogeneous films with the peak values of nanohardness 88 GPa and Young's modulus 517 GPa at the penetration depth of 26 nm and, respectively, 35 GPa and 275 GPa at 200 nm depth in 2 mu m thick film (Grishin et al 2014 JETP Lett. 100 680). The narrow range of sufficiently short target-to-substrate distance makes impossible to coat non flat specimens. To achieve ultimate BAM films' characteristics onto curved surfaces we developed two-step sputtering process. The first thin layer is deposited as a template at low RF power that facilitates a layered Frank van der Merwe mode growth of smooth film occurs. The next layer is grown at high RF target sputtering power. The affinity of subsequent flow of sputtered atoms to already evenly condensed template fosters the development of smooth film surface. As an example, we made BAM coating onto hemispherical 5 mm in diameter ball made from a hard tool steel and used as a head of a special gauge. Very smooth (6.6 nm RMS surface roughness) and hard AlMgB14 films fabricated onto commercial ball-shaped items enhance hardness of tool steel specimens by a factor of four.
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| 21. |
- Ignakhin, V. S., et al.
(författare)
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Tensile and torsional strain gauge based on Fe48Co32P14B6 metallic glass
- 2019
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Ingår i: Journal of Magnetism and Magnetic Materials. - : ELSEVIER SCIENCE BV. - 0304-8853 .- 1873-4766. ; 476, s. 382-386
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Tidskriftsartikel (refereegranskat)abstract
- We evaluate properties of the prototype of a strain gauge capable to discriminate different strain components: tension and torsion. It makes use of magnetoelastic effect in new Fe48Co32P14B6 metallic glass. As a sensing material, it surpasses characteristics of commercial Iron-Nickel Metglas (R) alloy: relative differential permeability of as quenched amorphous ribbon is of about 110000, the saturation induction B-s = 1.45 T, coercive field as low as 4 A/m, Curie temperature above 700 K, and significantly higher thermal stability. Different deformation components were determined through the analyses of the shape of hysteresis B-H loops. Fe-Co-P-B glass strain gauge can simultaneously detect as small tensile strains as 1.9 x 10(-5) and less than 0.13 deg/cm of torsional distortions.
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| 22. |
- Putrolaynen, V. V., et al.
(författare)
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UV patterning of vanadium pentoxide films for device applications
- 2007
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Ingår i: Journal of Physics D. - : IOP Publishing. - 0022-3727 .- 1361-6463. ; 40:17, s. 5283-5286
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Tidskriftsartikel (refereegranskat)abstract
- In this work we present the results of selective chemical etching of amorphous vanadium pentoxide films after their modification by ultraviolet ( UV) radiation. V2O5 resist can be either positive or negative, depending on the developer composition. It was shown that UV- exposed V2O5 films after development and vacuum annealing can be transformed into VO2 structures which exhibit an electrically induced resistance switching effect. The proposed method demonstrates the feasibility of using V2O5 as an effective inorganic resist material for ambient condition UV photomicrolithography. Also, this material has a great potential for fabrication of vanadium oxide- based devices.
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| 23. |
- Severikov, V. S., et al.
(författare)
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Magnetostriction in Fe80-xCoxP14B6 amorphous ribbons evaluated by Becker-Kersten method
- 2018
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Ingår i: Journal of Physics. - : Institute of Physics Publishing (IOPP).
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Konferensbidrag (refereegranskat)abstract
- Becker-Kersten method, which involves observing hysteresis M-H loops under mechanical stress, was applied to measure magnetostriction properties in amorphous rapid quenched ribbons Fe80-xCoxP14B6. It is shown that magnetostriction constant increases with the growth of cobalt atomic content from (1.75 ± 0.13)×10-6 for x = 25 to (1.60 ± 0.05)×10-5 for x = 40.
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| 24. |
- Severikov, V. S., et al.
(författare)
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Study of inverse magnetostrictive effect in metallic glasses Fe80-xCoxP14B6
- 2017
-
Ingår i: Journal of Physics, Conference Series. - : Institute of Physics Publishing (IOPP). - 1742-6588 .- 1742-6596. ; 929:1
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Tidskriftsartikel (refereegranskat)abstract
- The paper presents the possibility to build a tension gauge capable to discriminate different kinds of deformations: compression and twisting (induced by torsion strain) based on the magnetoelastic effect in new metallic glasses Fe80-xCoxP14B6. Applied loads increase coercive field H c, saturation induction B s and rectangularity of magnetic hysteresis loop. For example, hysteresis loop traced for 1 mm narrow, 50 cm long and 30 μm thick Fe40Co40P14B6 straight ribbon subjected to longitudinal stress of 346 MPa shown increased B s from 1.24 to 1.7 T and squareness from 0.55 to 0.88 compared to unloaded specimen. For twisting, on the contrary, both squareness and coercive field vary whereas the value of B s remains unchanged.
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| 25. |
- Timopheev, A. A., et al.
(författare)
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The influence of intergranular interaction on the magnetization of the ensemble of oriented Stoner-Wohlfarth nanoparticles
- 2009
-
Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 105:8
-
Tidskriftsartikel (refereegranskat)abstract
- The influence of interparticle interaction on the processes of magnetization reversal is considered for an ensemble of oriented Stoner-Wohlfarth nanoparticles. This is done through a solution of a kinetic equation describing the relaxation of the total magnetization to its equilibrium value in an effective mean field which includes a term proportional to the instantaneous value of the magnetization. It is shown that the interparticle interaction influences the temperature dependence of a coercive field. Under certain conditions, the presence of the interparticle interaction can lead to the formation of the so-called superferromagnetic state with the correlated directions of the magnetic moments of the particles. If the system is unable to come to the equilibrium during the time interval necessary to perform measurements, some measured quantities become dependent on the measurement time. It is shown that the blocking temperature T-b and the temperature dependence of coercive field at T < T-b are strongly dependent on a measurement time. At T>T-b, however, the coercivity, if exists, does not depend on the measurement time. The data of magnetostatic measurements, carried out on the (CoFeB)(x)-(SiO2)(1-x) nanogranular films with the concentration of ferromagnetic particles slightly lower than a percolation threshold, are in compliance with the results of the calculations.
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| 26. |
- Yuzvyuk, M. H., et al.
(författare)
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Processing of ultra-hard coatings based on AlMgB14 films
- 2016
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Ingår i: 18th International Conference PhysicA.SPb26–29 October 2015, Saint Petersburg, Russian Federation. - : Institute of Physics Publishing (IOPP).
-
Konferensbidrag (refereegranskat)abstract
- First time AlMgB14 films were prepared in Ames Lab by pulsed laser deposition technique. In this work, RF magnetron sputtering from a single stoichiometric target was employed to fabricate hard AlMgB14 coatings on Si wafer and industrial items. Measurements of nanohardness and elastic Young's modulus were performed to determine reliable strength characteristics of samples. Smooth 3 μm thick AlMgB14 films with the RMS surface roughness to be less than 1 nm exhibit hardness of 34 GPa and modulus of elasticity of 230 GPa at 20 mN peak load.
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| 27. |
- Adachi, N., et al.
(författare)
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Epitaxial Bi3Fe5O12(001) films grown by pulsed laser deposition and reactive ion beam sputtering techniques
- 2000
-
Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 88:5, s. 2734-2739
-
Tidskriftsartikel (refereegranskat)abstract
- We report on processing and comparative characterization of epitaxial Bi3Fe5O12 (BIG) films grown onto Gd-3(ScGa)(5)O-12[GSGG,(001)] single crystal using pulsed laser deposition (PLD) and reactive ion beam sputtering (RIBS) techniques. A very high deposition rate of about 0.8 mu m/h has been achieved in the PLD process. Comprehensive x-ray diffraction analyses reveal epitaxial quality both of the films: they are single phase, exclusively (001) oriented, the full width at half maximum of the rocking curve of (004) Bragg reflection is 0.06 deg for PLD and 0.05 deg for RIBS film, strongly in-plane textured with cube-on-cube film-to-substrate epitaxial relationship. Saturation magnetization 4 pi M-s and Faraday rotation at 635 nm were found to be 1400 Gs and -7.8 deg/mu m in PLD-BIG, and 1200 Gs and -6.9 deg/mu m in RIBS-BIG. Ferromagnetic resonance (FMR) measurements performed at 9.25 GHz yielded the gyromagnetic ratio gamma=1.797x10(7) l/s Oe, 1.826x10(7) l/s Oe; the constants of uniaxial magnetic anisotropy were K-u(*)=-8.66x10(4) erg/cm(3), -8.60x10(4) erg/cm(3); the cubic magnetic anisotropy K-1=-2.7x10(3) erg/cm(3),-3.8x10(3) erg/cm(3); and the FMR linewidth Delta H=25 and 34 Oe for PLD and RIBS films correspondingly. High Faraday rotation, low microwave loss, and low coercive field less than or equal to 40 Oe of BIG/GSGG(001) films promise their use in integrated magneto-optic applications.
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| 28. |
- Cortes-Perez, O., et al.
(författare)
-
Bragg difraction of optical guided waves by spin-dipole waves in double layer ferromagnetic wave guides
- 2008
-
Ingår i: Revista mexicana de física. - 0035-001X. ; 54:5, s. 376-381
-
Tidskriftsartikel (refereegranskat)abstract
- The peculiarities of the Bragg diffraction of optical guided waves (OGWs) by spin-dipole waves (SDWs) in a new ferrite heterostructure, based on Bi3Fe5O12(BIG) thin film deposited on a standard YIG/GGG (a Yttrium Iron Garnet thin film over a Galium Gadolinum Garnet substrate) sample, is presented. It is shown that the efficiency of waveguide magnetooptic interaction between OGWs and SDWs in BIG/YIG/GGG can be 4-14 times larger than in the standard YIG/GGG waveguide, even in the case when the interacting waves are localized in YIG waveguide layer.
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| 29. |
- Cortés-Pérez, O., et al.
(författare)
-
Difracción de Bragg de ondas ópticas guiadas por ondas de dipolo de spin en guías de onda ferromagnéticas de doble capa
- 2008
-
Ingår i: Revista Mexicana de Fisica. - 0035-001X. ; 54:5, s. 376-381
-
Tidskriftsartikel (refereegranskat)abstract
- The peculiarities of the Bragg diffraction of optical guided waves (OGWs) by spin-dipole waves (SDWs) in a new ferrite heterostructure, based on Bi3Fe5O12(BIG) thin film deposited on a standard YIG/GGG (a Yttrium Iron Garnet thin film over a Galium Gadolinum Garnet substrate) sample, is presented. It is shown that the efficiency of waveguide magnetooptic interaction between OGWs and SDWs in BIG/YIG/GGG can be 4-14 times larger than in the standard YIG/GGG waveguide, even in the case when the interacting waves are localized in YIG waveguide layer.
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| 30. |
- Denysenkov, V. P., et al.
(författare)
-
Broadband ferromagnetic resonance spectrometer
- 2003
-
Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 0034-6748 .- 1089-7623. ; 74:7, s. 3400-3405
-
Tidskriftsartikel (refereegranskat)abstract
- The continuous wave ferromagnetic resonance (FMR) spectrometer operating in multioctave (0.05-40 GHz) frequency range has been built to investigate the magnetic properties of thin ferromagnetic films in the temperature range of 4-420 K. The spectrometer has two probeheads: one is the X-band microwave reflection cavity used to perform express room temperature measurements and the other is an in-cryostat microstrip line probe to carry out FMR experiments covering the entire frequency range offered by the microwave source. Very uniform and stable magnetic field up to 2.4 T, temperature 4 K-420 K, and continuous frequency scan performed by an HP8722D vector network analyzer provide various modes of operation. Both probe heads are equipped with two-circle high precision goniometers to ensure accurate characterization of magnetic anisotropy and magnetostatic waves spectra recording. Use of the phase sensitive detection, utilized by magnetic field modulation at audio frequency and computer triggering of the network analyzer, enables broadband spectrometer sensitivity to be as high as 1.3x10(11) spins/Oe.
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| 31. |
- Emelchenko, G., et al.
(författare)
-
1.5 μm photoluminescence of Er3+ in opal based photonic crystals
- 2008
-
Ingår i: Proc SPIE Int Soc Opt Eng. - : SPIE. - 9780819471871
-
Konferensbidrag (refereegranskat)abstract
- The study of the emission properties of opal-erbium oxide nanocomposites in the wide range of erbium concentrations was carried out. Erbium oxide concentration was varied from 0.25 to 16%wt. Maximal output of the photoluminescence (PL) took place at 1%wt of erbium oxide concentration. It was shown that the annealing temperatures from 600 to 900°C were too low to exhibit sufficient emission properties of the erbium-opal composites. The presence of the erbium silicates Er2SiO5 and Er 2Si2O7 in the opal-erbium nanocomposites was revealed by X-ray phase analysis. Amorphous silica in opal matrix was not crystallized at the annealing during a few hours at 1000 - 1200°C. The case of the tens hours of annealing the crystoballite phase occurred. No angle dependence of the PL intensity was observed as a result of degradation of the photonic band gap (PBG) at the annealing of the opal-erbium oxide nanocomposites. Further modification of the material processing to achieve a strong photonic band gap reflection peak near 1550 nm with high PL intensity in the opal-Er2O3 composite is running.
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| 32. |
- Espeland, Marianne, et al.
(författare)
-
Combining target enrichment and Sanger sequencing data to clarify the systematics of the diverse Neotropical butterfly subtribe Euptychiina (Nymphalidae, Satyrinae)
- 2023
-
Ingår i: Systematic Entomology. - 0307-6970. ; 48:4, s. 498-570
-
Tidskriftsartikel (refereegranskat)abstract
- The diverse, largely Neotropical subtribe Euptychiina is widely regarded as one of the most taxonomically challenging groups among all butterflies. Over the last two decades, morphological and molecular studies have revealed widespread paraphyly and polyphyly among genera, and a comprehensive, robust phylogenetic hypothesis is needed to build a firm generic classification to support ongoing taxonomic revisions at the species level. Here, we generated a dataset that includes sequences for up to nine nuclear genes and the mitochondrial COI ‘barcode’ for a total of 1280 specimens representing 449 described and undescribed species of Euptychiina and 39 out-groups, resulting in the most complete phylogeny for the subtribe to date. In combination with a recently developed genomic backbone tree, this dataset resulted in a topology with strong support for most branches. We recognize eight major clades that each contain two or more genera, together containing all but seven Euptychiina genera. We provide a summary of the taxonomy, diversity and natural history of each clade, and discuss taxonomic changes implied by the phylogenetic results. We describe nine new genera to accommodate 38 described species: Lazulina Willmott, Nakahara & Espeland, gen.n., Saurona Huertas & Willmott, gen.n., Argentaria Huertas & Willmott, gen.n., Taguaiba Freitas, Zacca & Siewert, gen.n., Xenovena Marín & Nakahara, gen.n., Deltaya Willmott, Nakahara & Espeland, gen.n., Modica Zacca, Casagrande & Willmott, gen.n., Occulta Nakahara & Willmott, gen.n., and Trico Nakahara & Espeland, gen.n. We also synonymize Nubila Viloria, Andrade & Henao, 2019 (syn.n.) with Splendeuptychia Forster, 1964, Macrocissia Viloria, Le Crom & Andrade, 2019 (syn.n.) with Satyrotaygetis Forster, 1964, and Rudyphthimoides Viloria, 2022 (syn.n.) with Malaveria Viloria & Benmesbah, 2020. Overall, we revised the generic placement of 79 species (74 new generic combinations and five revised combinations), and as a result all but six described species of Euptychiina are accommodated within 70 named, monophyletic genera. For all newly described genera, we provide illustrations of representative species, drawings of wing venation and male and (where possible) female genitalia, and distribution maps, and summarize the natural history of the genus. For three new monotypic genera, Occulta gen.n., Trico gen.n. and Xenovena gen.n. we provide a taxonomic revision with a review of the taxonomy of each species and data from examined specimens. We provide a revised synonymic list for Euptychiina containing 460 valid described species, 53 subspecies and 255 synonyms, including several new synonyms and reinstated species.
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| 33. |
- Grishin, Alexander M., et al.
(författare)
-
Hard and Highly Adhesive AlMgB14 Coatings RF Sputtered on Tungsten Carbide and High-Speed Steel
- 2023
-
Ingår i: Materials. - : MDPI AG. - 1996-1944. ; 16:21
-
Tidskriftsartikel (refereegranskat)abstract
- We report a new industrial application of aluminum magnesium boride AlMgB14 (BAM) coatings to enhance the hardness of tungsten carbide ceramic (WC-Co) and high-speed steel tools. BAM films were deposited by RF magnetron sputtering of a single dense stoichiometric ceramic target onto commercial WC-Co turning inserts and R6M5 steel drill bits. High target sputtering power and sufficiently short target-to-substrate distance were found to be critical processing conditions. Very smooth (6.6 nm RMS surface roughness onto Si wafers) and hard AlMgB14 coatings enhance the hardness of WC-Co inserts and high-speed R6M5 steel by a factor of two and three, respectively. Complete coating spallation failure occurred at a scratch adhesion strength of 18 N. High work of adhesion and low friction coefficient, estimated for BAM onto drill bits, was as high as 64 J/m2 and as low as 0.07, respectively, more than twice the surpass characteristics of N-doped diamond-like carbon (DLC) films deposited onto nitride high-speed W6Mo5Cr4V2 steel.
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| 34. |
- Hollmark, M., et al.
(författare)
-
Processing and properties of soft magnetic Fe40Co40P14B6 amorphous alloy
- 2001
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Ingår i: IEEE transactions on magnetics. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9464 .- 1941-0069. ; 37:4, s. 2278-2280
-
Tidskriftsartikel (refereegranskat)abstract
- The Fe40Co40P14B6 metallic alloy has been prepared in a glassy state by a melt-spinning process. The 15-25 mum thick as-quenched, ribbons have superior soft magnetic properties compared with those of well-known Fe40Ni40P14B6 glass: the saturation magnetization is about 1.45 T, coercive field 4.0 A/m @ 0.1 Hz, incremental magnetic permeability mu (max) similar to 90 000 @ 60 Hz and Curie temperature above 700 K. The crystallization temperature, determined by differential scanning calorimeter, is approximately 60 K higher than that for FeNi-based alloy, indicating the enhanced thermal stability of FeCo-glass.
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| 35. |
- Kahl, S., et al.
(författare)
-
Optical transmission and Faraday rotation spectra of a bismuth iron garnet film
- 2003
-
Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 94:9, s. 5688-5694
-
Tidskriftsartikel (refereegranskat)abstract
- We prepared an epitaxial 530-nm-thick bismuth iron garnet (BIG) film on a Gd3Ga5O12(GGG) (111) substrate by pulsed laser deposition and measured spectra of optical transmission and magneto-optical Faraday rotation theta(F)(lambda) in visible light. Both spectra are shaped by the dispersion relations of the dielectric tensor and the effects of multiple-beam interference in the thin film. From fitting of the transmission spectrum, dispersion relations of the real and imaginary parts of the refractive index were found for the wavelength range from 515 to 1000 nm, n(lambda)=2.36+(413 nm/lambda)(2) and k(lambda)=(lambda/4pi nm)xexp[(1660 nm/lambda)(2)-15.2]. With these data as input information, a single diamagnetic line centered at lambda=486 nm was fitted to the experimentally recorded magneto-optical spectrum. The effects of thin film interference and surface roughness were included in order to closely reproduce the measured spectrum. The roughness determined from spectral analysis was compared to the rms roughness measured by atomic force microscopy. The values agree within a deviation of less than 20% and are approximately 3% of film thickness. The magneto-optical figure of merit 2\theta(F)\/alpha (alpha is the absorption coefficient) of our film increases strongly with wavelength and exceeds 100degrees at 740 nm. The optical efficiency for magneto-optical visualization \exp(-2alphad)sin(4theta(F)d)\ (d is film thickness) possesses a maximum value of 29% at 600 nm. Both quantities were calculated using the obtained dispersion relations for absorption and Faraday rotation.
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| 36. |
- Kim, H., et al.
(författare)
-
Giant Faraday rotation of blue light in epitaxial CexY3-xFe5O12 films grown by pulsed laser deposition
- 2001
-
Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 89:8, s. 4380-4383
-
Tidskriftsartikel (refereegranskat)abstract
- We report crystalline, magnetic, and magneto-optic (MO) properties of Ce-substituted yttrium iron garnet (CexY3-xFe5O12) thin films epitaxially grown onto single crystal Gd3Ga5O12 (111) substrates using Nd:YAG pulsed laser deposition technique. Oxygen ambient pressure used for the growth is found to be the critical parameter to prepare CexY3-xFe5O12 films with good crystalline and magnetic properties as well as large MO effect. The film fabricated at 50 m Torr oxygen pressure exhibits a maximum Faraday rotation (FR) theta (F)=1.78 and 4 degrees/mum at lambda =633 and 430 nm, respectively, a minimum in-plane coercivity H-c=35 Oe, and the narrowest full width at half maximum = 0.06 degrees for the (444) x-ray Bragg reflection rocking curve. The analog of the Verdet constant V=theta (F)/4 piM(s) also found to be dependent on the oxygen ambient pressure reaches a value as high as 1.41 degrees/mum kG at 633 nm, suggesting that this material is useful for MO applications. The energy dispersion FR spectra, measured over visible region 400 to 840 nm, clearly demonstrate that Ce substitution prominently enhances Faraday effect at 690 and at 430 nm blue-wavelength region.
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| 37. |
- Kolokoltsev, O. V., et al.
(författare)
-
Bragg diffraction of guided optical waves by spin dipole waves in a ferrimagnetic heterostructure
- 2009
-
Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 105:9
-
Tidskriftsartikel (refereegranskat)abstract
- The peculiarities of the Bragg diffraction of guided optical waves (GOWs) by spin-dipole waves (SDWs) in a ferrite heterostructure, based on Bi3Fe5O12 (BIG) thin film deposited on a standard YIG/GGG sample, is presented. It is shown that the efficiency of waveguide magneto-optic interaction between GOWs and SDWs in BIG/YIG/GGG can be 4-14 times large compared to the standard YIG/GGG waveguide, even in the case when the interacting waves are localized in YIG waveguide layer.
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| 38. |
- Kundozerova, Tatyana V., et al.
(författare)
-
Anodic Nb2O5 Nonvolatile RRAM
- 2012
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Ingår i: IEEE Transactions on Electron Devices. - 0018-9383 .- 1557-9646. ; 59:4, s. 1144-1148
-
Tidskriftsartikel (refereegranskat)abstract
- We report nonvolatile resistive switching in anodic niobium pentoxide thin-film memory cells. Highly dielectric Nb2O5 films were prepared at room temperature by the anodic oxidation of submicrometer-thick Nb films sputtered onto an Si wafer. After the electroforming process, Au/Nb2O5/Nb/Si sandwich memory cells demonstrate reproducible direct current and pulse mode switching between two resistance states with a resistance ON-OFF ratio around 10(3). Low and high resististive states show ohmic conductivity and field-assisted Poole-Frenkel-type conductivity, respectively. Nonvolatile resistance storage was traced within 40 days to quantify retention characteristics of the Nb2O5 memristor. The low-temperature anodic oxidation of Nb was found to be feasible to fabricate high-density cross-point memory with 3-D stack structures.
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| 39. |
- Kundozerova, T. V., et al.
(författare)
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Binary anodic oxides for memristor-type nonvolatile memory
- 2012
-
Ingår i: Physica Status Solidi. C, Current topics in solid state physics. - : Wiley. - 1610-1634 .- 1610-1642. ; 9:7, s. 1699-1701
-
Tidskriftsartikel (refereegranskat)abstract
- The temperature dependence of the optical properties of InGaAs/GaAs double quantum wells (QWs) grown by molecular beam epitaxy (MBE) on (100) and (311)A GaAs substrates has been studied by photoluminescence (PL). It is found that for an excitation of 50 mW, the PL quenching for (100) and (311)A QWs occurs at 220 K and 300 K, respectively. This suggests that the high index plane (311)A has superior structural properties and less non-radiative defect centers than the conventional (100) plane. The better optical quality of the QWs grown on (311)A is also confirmed by the narrowing of the full width at half-maximum (FWHM) of the PL emission: 10 nm for (311)A and 20 nm for (100). From these findings it is expected that optical devices grown on (311)A GaAs planes should have better performances than those grown on conventional (100) orientation. We have also carried out a systematic study to investigate the effect of post-growth thermal annealing on the optical quality of the QWs. We observed a substantial improvement of the PL efficiency with annealing temperatures in the range 500-700 °C for all samples. However, this PL enhancement is accompanied by a blueshift. These energy shifts can be explained by interdiffusion or intermixing of In and Ga atoms at the interfaces between the QWs and the barriers. A noticeable narrowing of the PL linewidth with higher annealing temperatures could be explained by a homogenisation of the quantum well interfaces.
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| 40. |
- Kuzovlev, Y. E., et al.
(författare)
-
Quantum discreteness effects and flicker fluctuations in tunneling conductivity
- 2002
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Ingår i: Physics of the solid state. - : Pleiades Publishing Ltd. - 1063-7834 .- 1090-6460. ; 44:5, s. 843-851
-
Tidskriftsartikel (refereegranskat)abstract
- An analysis of events in the tunneling junction shows that the interaction of one-electron processes in a many-electron system may be a source of scale-invariant low-frequency fluctuations of conductivity (the interaction consists in that the quantum probability of an electron transition depends on fast random changes in the environment in the course of the transition, including the changes caused by analogous transitions). The theory relates flicker fluctuations in the tunneling conductivity to the discrete character of the spectrum of electron states and explains the nonlinearity of the noise-current characteristic observed in nanocomposites.
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| 41. |
- Kuzovlev, Y. E., et al.
(författare)
-
Rapidly fluctuating fields as a source of low-frequency conductivity fluctuations and the size effects in quantum kinetics
- 2000
-
Ingår i: JETP Letters. - : Pleiades Publishing Ltd. - 0021-3640 .- 1090-6487. ; 72:11, s. 574-577
-
Tidskriftsartikel (refereegranskat)abstract
- Tunneling contact was taken as an example to demonstrate that the interaction of electron quantum transitions can serve as a source of low-frequency flicker fluctuations of conductivity. Estimates are made for the fluctuations of tunnel conductance. The theory explains the effect of flicker noise sensitivity to the discreteness of the electronic spectrum, as it was observed in nanocomposites.
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| 42. |
- Liu, Yanjie, et al.
(författare)
-
The conserved plant sterility gene HAP2 functions after attachment of fusogenic membranes in Chlamydomonas and Plasmodium gametes
- 2008
-
Ingår i: Genes & Development. - : Cold Spring Harbor Laboratory Press (CSHL). - 0890-9369 .- 1549-5477. ; 22:8, s. 1051-1068
-
Tidskriftsartikel (refereegranskat)abstract
- The cellular and molecular mechanisms that underlie species-specific membrane fusion between male and female gametes remain largely unknown. Here, by use of gene discovery methods in the green alga Chlamydomonas, gene disruption in the rodent malaria parasite Plasmodium berghei, and distinctive features of fertilization in both organisms, we report discovery of a mechanism that accounts for a conserved protein required for gamete fusion. A screen for fusion mutants in Chlamydomonas identified a homolog of HAP2, an Arabidopsis sterility gene. Moreover, HAP2 disruption in Plasmodium blocked fertilization and thereby mosquito transmission of malaria. HAP2 localizes at the fusion site of Chlamydomonas minus gametes, yet Chlamydomonas minus and Plasmodium hap2 male gametes retain the ability, using other, species-limited proteins, to form tight prefusion membrane attachments with their respective gamete partners. Membrane dye experiments show that HAP2 is essential for membrane merger. Thus, in two distantly related eukaryotes, species-limited proteins govern access to a conserved protein essential for membrane fusion.
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| 43. |
- Lyfar, D. L., et al.
(författare)
-
Microwave absorption in a thin La0.7Sr0.3MnO3 film : Manifestation of colossal magnetoresistance
- 2004
-
Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 69:10
-
Tidskriftsartikel (refereegranskat)abstract
- Microwave (MW) absorption by a thin La0.7Sr0.3MnO3 film on a SrTiO3 substrate is investigated at a 9.1 GHz as a function of a dc magnetic field. Features of this absorption, namely, the jump in the absorption derivative, have been detected as the applied field passes through its zero value. Hysteretic behavior of the jumps is also observed. The results are discussed based on the model in which MW losses, additional to the ferromagnetic resonance, arise due to attenuation of MW currents induced in the sample by both variable magnetic induction and MW electrical field near the substrate surface with high dielectric permittivity. We show that zero-field anomalies in MW absorption are directly coupled with manganite magnetoresistive properties.
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| 44. |
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| 45. |
- Markovich, V., et al.
(författare)
-
Inverse thermal hysteresis and Peculiar Transport Properties of La(0.9)MnO(3-delta) film
- 2010
-
Ingår i: Journal of Physics, Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 200, s. 052014-
-
Tidskriftsartikel (refereegranskat)abstract
- Magnetic and transport properties of 100 nm thick La(0.9)MnO(3-delta) manganite films have been studied in the temperature range 5 - 300 K. The films exhibit a paramagnetic to ferromagnetic transition at T(C) approximate to 194 K. The temperature dependence of the resistivity shows a metal-insulator transition at 204 K and a strong resistivity increase at temperatures T < 160 K. Variations of resistivity with magnetic field and current are non-hysteretic, while the temperature dependence of the resistivity exhibits unusual inverse thermal hysteresis. The magnetic field independent inverse thermal hysteresis depends significantly on the thermal history of the sample. The data suggests that nonlinear transport characteristics are attributed to inelastic tunneling through intrinsic tunnel juctions formed by phase separated ferromagnetic metallic domains and insulating antiferromagnetic matrics.
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| 46. |
- Markovich, V., et al.
(författare)
-
Magnetic separation and inelastic tunneling in self-doped manganite films
- 2009
-
Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 106:4
-
Tidskriftsartikel (refereegranskat)abstract
- Magnetic and transport properties of 100 nm thick La0.9MnO3-delta self-doped manganite films have been investigated in the temperature range 5-300 K. The films exhibit a paramagnetic to ferromagnetic transition at T-C = 194 K. The temperature dependence of the resistivity shows a metal-insulator transition at 204 K and a strong resistivity increase below 160 K. The magnetoresistance was always negative and slightly bias dependent. Variations in resistivity with magnetic field and current are nonhysteretic, while the temperature dependence of the resistivity exhibits unusual inverse thermal hysteresis. The magnetic field independent inverse thermal hysteresis is strongly influenced by a thermal history of the sample. The data suggest that nonlinear low temperature transport is dominated by inelastic tunneling through intrinsic tunnel junctions formed by phase-separated ferromagnetic metallic domains and insulating anti ferromagnetic matrix.
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| 47. |
- Medvedev, Y. V., et al.
(författare)
-
The charge state of conducting fine-dispersed systems in an insulating matrix
- 2001
-
Ingår i: Physics of the solid state. - : Pleiades Publishing Ltd. - 1063-7834 .- 1090-6460. ; 43:5, s. 935-940
-
Tidskriftsartikel (refereegranskat)abstract
- The influence of fluctuations in the number of Fermi particles on the charge state of fine-dispersed metallic grains in an insulating matrix is investigated. It is suggested that the system of grains does not form a tunnel medium and that charge transfer between metallic elements of the composite occurs due to thermal excitations of electrons over barriers. As follows from a calculation of the grand partition function, the average charge of the ith grain is a nonlinear function of the potential V-i of the conductor.
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| 48. |
- Medvedev, Y. V., et al.
(författare)
-
The diagnostics of thermal kinetic coefficients for the optimization of film bolometer properties
- 2002
-
Ingår i: Technical physics. - : Pleiades Publishing Ltd. - 1063-7842 .- 1090-6525. ; 47:1, s. 114-120
-
Tidskriftsartikel (refereegranskat)abstract
- A pulsed microwave technique for the fast and accurate diagnostics of a complete set of thermal kinetic coefficients in single-layer film structures is developed. The technique is tested on La-0.7(Pb0.7Sr0.3)(0.3)MnO3 films on LaAlO3 and SrTiO3 substrates-the structures featuring a temperature resistance coefficient of 5-7%, which is the highest for manganite-containing materials at room temperature. The results of numerical simulation show that the performance of the uncooled bolometers can be improved by optimizing the thermal conductivity of the substrate and matching the thermal resistances of the film-substrate and substrate-thermostat interfaces.
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| 49. |
- Murzina, T. V., et al.
(författare)
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Nonlinear magneto-optical effects in all-garnet magnetophotonic crystals
- 2009
-
Ingår i: Journal of Magnetism and Magnetic Materials. - : Elsevier BV. - 0304-8853 .- 1873-4766. ; 321:7, s. 836-839
-
Tidskriftsartikel (refereegranskat)abstract
- Nonlinear magneto-optical properties of all-garnet magnetophotonic crystals composed of alternating layers of ferromagnetic Bi3Fe5O12 ( BIG) and Sm3Ga5O12 quarter-wavelength layers with a half-wavelength BIG microcavity mode are presented. The samples are grown by rf-magnetron sputtering on non-magnetic GGG substrate. Many-fold enhancement of the magnetization-induced effects in second-harmonic generation (SHG) as compared with linear magneto-optical effects are observed: the SHG magnetic contrast up to 50% and magnetization-induced rotation of the polarization plane of about 901 are measured at the resonance microcavity wavelengh of lambda = 779 nm. (C) 2008 Elsevier B. V. All rights reserved.
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| 50. |
- Nasibulin, Albert G., et al.
(författare)
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A novel cement-based hybrid material
- 2009
-
Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 11
-
Tidskriftsartikel (refereegranskat)abstract
- Carbon nanotubes (CNTs) and carbon nanofibers (CNFs) are known to possess exceptional tensile strength, elastic modulus and electrical and thermal conductivity. They are promising candidates for the next-generation high-performance structural and multi-functional composite materials. However, one of the largest obstacles to creating strong, electrically or thermally conductive CNT/CNF composites is the difficulty of getting a good dispersion of the carbon nanomaterials in a matrix. Typically, time-consuming steps of purification and fimctionalization of the carbon nanomaterial are required. We propose a new approach to grow CNTs/CNFs directly on the surface of matrix particles. As the matrix we selected cement, the most important construction material. We synthesized in a simple one-step process a novel cement hybrid material (CHM), wherein CNTs and CNFs are attached to the cement particles. The CHM has been proven to increase 2 times the compressive strength and 40 times the electrical conductivity of the hardened paste, i.e. concrete without sand. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.
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