| 1. |
- 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-
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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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| 2. |
- 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-
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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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| 3. |
- Shkar, V. F., et al.
(författare)
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Structure and properties of deposited yttrium iron garnet films
- 2005
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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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| 4. |
- Voloshin, V. A., et al.
(författare)
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Interplay of structure, magnetism and resistivity of La0.5Ca0.54MnO3+x
- 2000
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Ingår i: Physics Letters A. - 0375-9601 .- 1873-2429. ; 271:02-jan, s. 121-127
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Tidskriftsartikel (refereegranskat)abstract
- The structure of La0,5Ca0,5MnO3 is well known for T> 250 K and T( 150 K. But in the intermediate region some structure characteristics are difficult to understand [1]. This Letter studies in this temperature region the interrelation between structure and the experimental data like magnetism and resistivity on the basis of a vibron-electron dynamic equilibrium hypothesis. It has been shown that behavior of paramagnetic-to-ferromagnetic transition can be explaned in the framework of this hypothesis.
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| 5. |
- Grishin, Alexander M., et al.
(författare)
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Green and blue magneto-optical photonic crystals
- 2012
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Ingår i: Thin Solid Films. - : Elsevier BV. - 0040-6090 .- 1879-2731. ; 520:9, s. 3647-3650
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Tidskriftsartikel (refereegranskat)abstract
- A series of one-dimensional heteroepitaxial all-garnet magneto-optical photonic crystals (MOPCs) were pulsed laser deposited to operate at 550 and 470 nm wavelength. We explored the concept of blue shift of the optical absorption edge of ferric ions by substituting Fe with Ga on the tetrahedral sites as well as Bi and Y, respectively, with Ca and Ce at the dodecahedral coordinated positions. 17-layered [Y2Ce1Fe5O12/Gd3Ga5O12] MOPC with a total thickness of 968 nm demonstrates superior magneto-optical performance: Faraday rotation theta(Fmax) = + 2.0 degrees and transmittance as high as 0.35 at the resonance wavelength of 470 nm.
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| 6. |
- Grishin, Alexander M., et al.
(författare)
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Luminescent Magneto-Optical Photonic Crystals
- 2012
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Ingår i: ASIA-PACIFIC INTERDISCIPLINARY RESEARCH CONFERENCE 2011 (AP-IRC 2011). - : IOP Publishing. ; , s. 012007-
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- We compare luminescent properties of several Er-doped garnet films as building blocks in all-garnet heteroepitaxial magneto-optical photonic crystals: La3Ga5O12, Gd3Ga5O12, Y3Fe5O12, Bi3Fe5O12, and Bi2.97Er0.03Fe4Al0.5Ga0.5O12. Er substituents on the dodecahedral lattice sites do not decrease giant Faraday rotation in Bi3Fe5O12 garnet; meanwhile providing intense room temperature C-band photoluminescence (PL). Fe3+ ion works as a sensitizer for Er resulting in fivefold PL enhancement in iron garnets compared to gallium ones. PL lifetime in gallium garnets is in millisecond range reaching 6 ms in Gd2.9Er0.1Ga5O12. The first luminescent one-dimensional heteroepitaxial all-garnet magneto-optical (MO) photonic crystal was composed from diamagnetic Sm3Ga5O12 and MO-active Bi2.97Er0.03Fe4Al0.5Ga0.5O12 garnet layers by rf-magnetron sputtering on Gd3Ga5O12(111) substrate. Substitution of ferric ions by aluminum and gallium improved transparency and induced perpendicular anisotropy in pure Bi3Fe5O12. Photonic crystals owned a record high magneto-optical quality and a latching type (magnetic remnant) Faraday rotation (FR). At the resonance wavelength 775 nm, specific FR theta(F) = -14.1 deg/mu m and MO-quality factor Q = 99.3 deg represent the highest MO performance achieved so far. Long-lived near-IR luminescence in Er substituted gallium and iron garnet layers used both as Bragg mirrors and microcavities promises magneto-optical photonic crystals to become an active lasing medium.
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| 7. |
- Hollmark, M., et al.
(författare)
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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
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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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| 8. |
- Jalalian, Abolfazl, et al.
(författare)
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Ferromagnetic resonance in Y(3)Fe(5)O(12) nanofibers
- 2011
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 99:10, s. 102501-
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Tidskriftsartikel (refereegranskat)abstract
- Continuous bead-free polycrystalline yttrium iron garnet (YIG) nanofibers 100 mu m long and 50-100 nm in diameter were sintered by sol-gel calcination assisted electrospinning. Room temperature ferromagnetism in YIG fibers is indicated by a well formed M-H hysteresis loop with about 70% of remnant magnetization to the saturated value reached at 150 Oe. Broad band microwave spectroscopy revealed strong asymmetry of ferromagnetic resonance lines that conforms to a three orders of magnitude shape aspect ratio of YIG nanofibers.
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| 9. |
- Kucherenko, S. S., et al.
(författare)
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The P-H-T effects on the electric resistance and magnetoresistance of La0.7Sr0.1Pb0.2MnO3 single crystal films
- 2001
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Ingår i: Technical physics letters. - : Pleiades Publishing Ltd. - 1063-7850 .- 1090-6533. ; 27:6, s. 451-453
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Tidskriftsartikel (refereegranskat)abstract
- The effects of high hydrostatic pressures (P) and magnetic fields (H) in a broad temperature range (T = 77-325 K) on the electric resistance (R) and magnetoresistance (DeltaR/R-0) was studied in laser-deposited La0.7Sr0.1Pb0.2MnO3 single crystal films on (100)-oriented SrTiO3 substrates. A maximum response to the P and H variations was observed in the temperature interval of phase transitions (T = 310-325 K). A growth in the pressure P leads to an increase in both R and DeltaR/R-0 values, while an increase in the magnetic field strength H is accompanied by an increase in DeltaR/R-0 and a drop in the electric resistance R of the single crystal films studied.
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| 10. |
- Linnarsson, Margareta K., et al.
(författare)
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Mn implantation for new applications of 4H-SiC
- 2012
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Ingår i: Silicon Carbide and Related Materials 2011. - : Trans Tech Publications Inc.. - 9783037854198 ; , s. 221-224
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Konferensbidrag (refereegranskat)abstract
- Structural disorder and lattice recovery of high dose, manganese implanted, semiinsulating, 4H-SiC have been studied by secondary ion mass spectrometry, Rutherford backscattering in channeling directions, visible-to-near infrared optical spectroscopy as well as with transmission electron microscopy. After heat treatment at 1400 and 1600 °C, a substantial rearrangement of manganese is observed in the implanted region. However, the crystal has not been fully recovered. More disorder remains in the [1123] compared to the [0001] channel direction. Stacking faults, voids and 3C inclusions are observed in the implanted region. A Mn containing phase has most likely formed.
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