| 1. |
- Adamczewski-Musch, J., et al.
(författare)
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Production and electromagnetic decay of hyperons : a feasibility study with HADES as a phase-0 experiment at FAIR
- 2021
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Ingår i: European Physical Journal A. - : Springer Nature. - 1434-6001 .- 1434-601X. ; 57:4
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Tidskriftsartikel (refereegranskat)abstract
- A feasibility study has been performed in order to investigate the performance of the HADES detector to measure the electromagnetic decays of the hyperon resonances Sigma(1385)(0), Lambda(1405) and Lambda(1520) as well as the production of double strange baryon systems Xi(-) and Lambda Lambda in p + p reactions at a beam kinetic energy of 4.5GeV. The existing HADES detector will be upgraded by a new Forward Detector, which extends the detector acceptance into a range of polar angles that plays a crucial role for these investigations. The analysis of each channel is preceded by a consideration of the production cross-sections. Afterwards the expected signal count rates using a target consisting of either liquid hydrogen or polyethylene are summarized.
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| 2. |
- Ovsyannikov, Gennady, 1948, et al.
(författare)
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Proximity effect and electron transport in oxide hybrid heterostructures with superconducting/magnetic interfaces
- 2011
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Ingår i: Superconductor Science and Technology. - : IOP Publishing. - 0953-2048 .- 1361-6668. ; 24:5, s. Art. no. 055012-
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Tidskriftsartikel (refereegranskat)abstract
- We report on electron transport in oxide heterostructures with superconducting/magnetic (S/M) thin film interfaces. The investigated hybrid mesa-heterostructures consist of a cuprate superconductor, a nonsuperconducting cuprate (antiferromagnetic) or manganite (ferromagnetic) interlayer with thickness d(M) = 5-50 nm and a conventional superconductor (Nb). The superconducting critical current (I-C) with a critical current density j(c) = 10(3) A cm(-2) (for d(M) = 10 nm) and a characteristic voltage ICRN = 100-200 mu V (RN is normal resistance) are observed at liquid helium temperature for a CaXSr1-XCuO2 antiferromagnetic cuprate interlayer with a thickness of d(M) = 10-50 nm. The superconducting current-phase relation of heterostructures deviates from the regular sine type, demonstrating a second harmonic component. These hybrid heterostructures with S/M interfaces show unusually high sensitivity to external magnetic fields. When substituting the cuprate interlayer by a manganite film, no critical current was observed although the manganite interlayer was made several times thinner (down to d(M)
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| 3. |
- Constantinian, K. Y., et al.
(författare)
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Electron transport and microwave dynamics of hybrid Nb/Au/CaSrCuO/YBaCuO planar Josephson junctions
- 2009
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Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 234:4, s. Art. no. 042004-
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Konferensbidrag (refereegranskat)abstract
- We report on measurements of dc electron transport and microwave dynamics of thin film hybrid Josephson junctions with an oxide antiferromagnetic interlayer. The base superconducting electrode YBaCuO and the antiferromagnetic (AF) interlayer CaSrCuO (with thickness d 20 - 70 nm) were grown by laser ablation on NdGaO3 substrates. I-V curves were well fitted to RSJ model and had no excess current, ICRN products were of order 0.2 mV at T=4.2 K. We did not observe any noticeable reduction of I CRN with increasing d. Such "tunnellike" behaviour also resulted in appearance of singularities on I-V curve when magnetic field was applied. Oscillating with microwave power integer and half-integer Shapiro steps were registered along with sub-harmonic detector response. Moreover, for some of junctions a "devil" staircase structure was observed on I-V curves and giant noise-like signals were measured in 1-2 GHz band at the certain levels of microwave power. Observed features, noise performance and the impact of the second harmonic in current-phase relation on junction dynamics are discussed taking into account data for structures without AF interlayer.
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| 4. |
- Zaǐtsev, A. V., et al.
(författare)
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Superconducting current in hybrid structures with an antiferromagnetic interlayer
- 2010
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Ingår i: Journal of Experimental and Theoretical Physics. - 1090-6509 .- 1063-7761. ; 110:2, s. 336-344
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Tidskriftsartikel (refereegranskat)abstract
- It is shown experimentally that the superconducting current density in Nb/Au/Ca1 - x Sr (x) CuO2/YBa2Cu3O7 - delta hybrid superconducting heterostructures with a Ca1 - x Sr (x) CuO2 anti-ferromagnetic (AF) cuprate interlayer is anomalously high for interlayer thicknesses d (M) = 10-50 nm and the characteristic damping length for superconducting correlations is on the order of 10 nm. The experimental results are explained on the basis of theoretical analysis of a junction of two superconductors (S' and S) connected by a magnetic multilayer with the AF ordering of magnetization in the layers. It is shown that with such a magnetization ordering, anomalous proximity effect determined by the singlet component of the condensate wavefunction may take place. As a result, the critical currents in S'/I/AF/S and S'/I/N/S structures (I denotes an insulator, and N, the normal metal) may coincide in order of magnitude even when the thickness of the AF interlayer considerably exceeds the decay length of the condensate wavefunction in ferromagnetic layers.
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| 5. |
- Demidov, V. V., et al.
(författare)
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Magnetic anisotropy in strained manganite films and bicrystal junctions
- 2013
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 113:16
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Tidskriftsartikel (refereegranskat)abstract
- Transport and magnetic properties of La0.67Sr0.33MnO3 (LSMO) manganite thin films and bicrystal junctions were investigated. Epitaxial manganite films were grown on SrTiO3, LaAlO3, NdGaO3 (NGO), and (LaAlO3)(0.3) + (Sr2AlTaO6)(0.7) substrates, and their magnetic anisotropy were determined by two independent techniques of magnetic resonance spectroscopy. It was demonstrated that by using these techniques, a small (0.3%) anisotropy of crystal structure at the (110) surface plane of the orthorhombic NGO substrate leads to uniaxial magnetic anisotropy of the films in the plane of the substrate at least at the room temperature. It was found that on vicinal NGO substrates, the value of magnetic anisotropy strength can be varied in the range 100-200 Oe at T = 295 K by changing the substrate vicinal angle from 0 degrees to 25 degrees. Measurement of the magnetic anisotropy of manganite bicrystal junction demonstrated the presence of two ferromagnetic spin subsystems for both types of bicrystal boundaries with tilting of basal plane of manganite tilted bicrystal (TB-junction) and with rotation of crystallographic axes (RB-junction) used for comparison. The magnetoresistance of TB-junctions increases with decreasing temperature and the misorientation angle. Variation of bicrystal misorientation angle does not lead to change of misorientation of easy magnetic axes in the film parts forming TB-junction. Analysis of the voltage dependencies of bicrystal junction conductivity show that the low value of the magnetoresistance for the LSMO bicrystal junctions can be caused by two scattering mechanisms. The first one is the spin-flip of spin-polarized carriers due to the strong electron-electron interactions in a disordered layer at the bicrystal boundary at low temperatures and the second one is spin-flip by antiferromagnetic magnons at high temperatures.
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| 6. |
- Ovsyannikov, Gennady, 1948, et al.
(författare)
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Anomalous proximity effect in superconducting oxide structures with an antiferromagnetic layer
- 2006
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Ingår i: JETP Letters. - 1090-6487 .- 0021-3640. ; 84:5, s. 262-266
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Tidskriftsartikel (refereegranskat)abstract
- The electrophysical parameters of superconductor/antiferromagnetic insulator structures based on the Nb/Au/Ca1-x Sr x CuO2/YBa2Cu3O7-δ hybrid heterostructure have been examined. YBa2Cu3O 7-δ and Ca1-x Sr x SuO2 epitaxial films are grown by the laser ablation method on NdGaO3 single crystal substrates, the thickness of the Ca1-x Sr x CuO2 layer varies from 20 to 50 nm, and x = 0.15 and 0.5. The superconducting pair potential in the interface between the YBa 2Cu3O7-δ superconductor and Ca 1-x Sr x CuO2 antiferromagnet is found to penetrate into the antiferromagnet at distances much larger than the coherence length calculated for the ferromagnetic layer. The critical current of the superconducting transition manufactured at such an interface is highly sensitive to the magnetic field.
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| 7. |
- Demidov, V. V., et al.
(författare)
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Magnetic Anisotropy of Strained Epitaxial Manganite Films
- 2011
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Ingår i: Journal of Experimental and Theoretical Physics. - : Pleiades Publishing Ltd. - 1090-6509 .- 1063-7761. ; 112:5, s. 825-832
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Tidskriftsartikel (refereegranskat)abstract
- The in-plane magnetic anisotropy of epitaxial La(0.7)Sr(0.3)MnO(3) (LSMO) films is studied at room temperature by the following three independent techniques: magnetooptical Kerr effect, ferromagnetic resonance at a frequency of 9.61 GHz, and recording of absorption spectra of electromagnetic radiation at a frequency of 290.6 MHz. The films are deposited onto NdGaO(3) (NGO) substrates in which the (110) NGO plane is tilted at an angle of 0-25.7 degrees to the substrate plane. The uniaxial magnetic anisotropy induced by the strain of the film is found to increase with the tilt angle of the (110) NGO plane. A model is proposed to describe the change in the magnetic anisotropy energy with the tilt angle. A sharp increase in the radio-frequency absorption in a narrow angular range of a dc magnetic field near a hard magnetization axis is detected The anisotropy parameters of the LSMO films grown on (110) NGO, (001) SrTiO(3), and (001)[(LaAlO(3))(0.3) + (Sr(2)AlTaO(6))(0.7)] substrates are compared.
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| 8. |
- Kislinskiǐ, Yu V., et al.
(författare)
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Copper oxide superconducting/antiferromagnetic interface
- 2015
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Ingår i: Solid State Phenomena. - 1662-9779 .- 1012-0394. - 9783038354826 ; 233-234, s. 733-736
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Konferensbidrag (refereegranskat)abstract
- Superconducting Nb/Au/Ca1-xSrxCuO2/YBa2Cu3O7 mesa-heterostructures were investigated. Dependencies of electrical parameters versus inverse capacitance were measured. A band diagram which takes into account an accumulation of holes inCa1-xSrxCuO2 interlayer and band bending due to difference of work functions was proposed. The dependencies of electrical parameters were analyzed by examining the quasipartical and superconducting currents.
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| 9. |
- Kislinskiǐ, Yu V., et al.
(författare)
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Magnetically Dependent Superconducting Transport in Oxide Heterostructures with an Antiferromagnetic Layer
- 2008
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Ingår i: Journal of Experimental and Theoretical Physics. - 1090-6509 .- 1063-7761. ; 106:4, s. 800-805
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Tidskriftsartikel (refereegranskat)abstract
- The superconducting current in hybrid superconducting structuresNb/Au/Ca1−xSrxCuO2/YBa2Cu3O7 –δwith an antiferromagnetic layer is experimentally shown to have aJosephson nature, and the deviation from the sinusoidal dependence of the superconducting current on thephase difference between superconducting electrodes is about 20% of the second harmonic. These heterostructuresare found to have sensitivity to an applied magnetic field that is much higher than that of conventionalJosephson junctions. The experimental shape of the magnetic-field dependence of the critical current in the heterostructuresdiffers from the usual Fraunhofer shape by oscillation with a significantly smaller period along amagnetic field.PACS numbers: 74.45.+c, 74.50.+r, 75.70.Cn
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| 10. |
- Ovsyannikov, Gennady, 1948, et al.
(författare)
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Magnetotransport characteristics of strained La0.7Sr0.3MnO3 epitaxial manganite films
- 2009
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Ingår i: Journal of Experimental and Theoretical Physics. - 1090-6509 .- 1063-7761. ; 108:1, s. 48-55
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Tidskriftsartikel (refereegranskat)abstract
- The electrical and magnetic characteristics of La0.7Sr0.3MnO3 (LSMO) epitaxial manganite films are investigated by different methods under conditions when the crystal structure is strongly strained as a result of mismatch between the lattice parameters of the LSMO crystal and the substrate. Substrates with lattice parameters larger and smaller than the nominal lattice parameter of the LSMO crystal are used in experiments. It is shown that the behavior of the temperature dependence of the electrical resistance for the films in the low-temperature range does not depend on the strain of the film and agrees well with the results obtained from the calculations with allowance made for the interaction of electrons with magnetic excitations in the framework of the double-exchange model for systems with strongly correlated electronic states. Investigations of the magneto- optical Kerr effect have revealed that an insignificant (0.3%) orthorhombic distortion of the cubic lattice in the plane of the NdGaO3(110) substrate leads to uniaxial anisotropy of the magnetization of the film, with the easy-magnetization axis lying in the substrate plane. However, LSMO films on substrates (((LaAlO3)(0.3)+(Sr2AlTaO6)(0.7))(001)) ensuring minimum strain of the films exhibit a biaxial anisotropy typical of cubic crystals. The study of the ferromagnetic resonance lines at a frequency of 9.76 GHz confirms the results of magnetooptical investigations and indicates that the ferromagnetic phase in the LSMO films is weakly inhomogeneous.
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