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A. M. Petrzhik G. A. Ovsyannikov A. V. Shadrin K. I. Konstantinyan A. V. Zaitsev V. V. Demidov Yu. V. Kislinskii 《Journal of Experimental and Theoretical Physics》2011,112(6):1042-1050
Hybrid herostructures comprising an YBa2Cu3O
x
(YBCO) high-temperature superconductor (HTS) layer and Nb/Au low-temperature superconductor (LTS) bilayer (with critical
HTS and LTS temperatures T
c and T′c, respectively), separated by a thin (d
M = 5–20 nm) interlayer of LaMnO3, La0.7Ca0.3MnO3, or La0.7Sr0.3MnO3 manganite have been studied. The electric resistance and magnetic properties of individual (evaporated directly onto the
substrate) manganite films and related hybrid herostructures have been measured. Based on quasi-classical equations, analytical
expressions for the conductivity of herostructures at T ≤ T′c are obtained in the case of a low-transparency superconductor/manganite interface. It is established that the conductivity
of heterostructures is determined by the proximity effect (related to the penetration of a condensate wavefunction from the
Nb/Au bilayer to manganite) and depends strongly on interface transparency. At low temperatures (T ≪ T
c′), the conductivity peaks are found at voltages determined by the exchange field of the manganite interlayer. At T
c′ < T < T
c, conductivity features at nearly zero bias voltages are observed, which are related to the superconductivity of the YBCO
electrode. 相似文献
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G. A. Ovsyannikov Yu. V. Kislinskii K. Y. Constantinian A. V. Shadrin V. V. Demidov A. M. Petrzhik 《Journal of Experimental and Theoretical Physics》2017,124(4):628-634
We have studied the current transport and magnetism in epitaxial hybrid superconducting mesa structures consisting of a cuprate superconductor and superconducting niobium with a manganite LaMnO3 (LMO) interlayer. We have shown experimentally using magnetic resonance that the magnetization, magnetic anisotropy parameters, and transition temperature to the ferromagnetic state of the interlayer of the structures are analogous to those of an autonomous LMO film grown on a neodymium gallate substrate. The estimate of the barrier height obtained from the dependence of the characteristic resistance of mesa structures on the interlayer thickness has shown the barrier height variation with the thickness in the range of 5–30 mV. The temperature dependences of the conductivity of the mesa structure in the range between superconducting transition temperatures of the superconductors can be described in the theory taking into account the d-wave nature of the superconductivity for one of the electrodes and the spin-filtering of carriers passing through the tunnel interlayer. Spin-filtering is confirmed by the tunnel magnetoresistance and the high sensitivity of mesa structures to a weak external magnetic field in a voltage interval smaller than the gap of niobium. 相似文献
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NL Asfandiarov AI Fokin VG Lukin EP Nafikova GS Lomakin VS Fal'ko YV Chizhov 《Rapid communications in mass spectrometry : RCM》1999,13(12):1116-1123
A series of anthraquinone (C(14)O(2)H(8)) derivatives has been studied by means of electron capture negative ion mass spectrometry (ECNI-MS), photoelectron spectroscopy (PES), and AM1 quantum chemical calculations. Mean lifetimes of molecular negative ions M(-.) (MNI) have been measured. The mechanism of long-lived MNI formation in the epithermal energy region of incident electrons has been investigated. A simple model of a molecule (a spherical potential well with the repulsive centrifugal term) has been applied for the analysis of the energy dependence of cross sections at the first stage of the electron capture process. It has been shown that a temporary resonance of MNI at the energy approximately 0.5 eV corresponds to a shape resonance with lifetime 1-2.10(-13) s in the f-partial wave (l = 3) of the incident electron. The next resonant state of MNI at the energy approximately 1.7 eV has been associated with the electron excited Feshbach resonance (whose parent state is a triplet npi* transition). In all cases the initial electron state of the MNI relaxes into the ground state by means of a radiationless transition, and the final state of the MNI is a nuclear excited resonance with a lifetime measurable on the mass spectrometry timescale. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
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P. V. Komissinski G. A. Ovsyannikov Yu. V. Kislinskii I. M. Kotelyanskii Z. G. Ivanov 《Journal of Experimental and Theoretical Physics》2002,95(6):1074-1084
Conductance anomalies at low bias voltages and superconducting currents in Au/YBa2Cu3Ox and Nb/Au/YBa2Cu3Ox heterojunctions in which the c axis of the YBa2Cu3Ox (YBCO) epitaxial film is rotated in the (110) YBCO plane through 11° with respect to the normal to the substrate plane were studied experimentally. The films were prepared by laser deposition onto (7 2 10)-oriented NdGaO3 substrates. The current-voltage characteristics of the heterojunctions exhibit conductance anomalies at low voltages. The behavior of these anomalies is studied at various temperatures and in various magnetic fields. The critical current and Shapiro steps observed in the current-voltage characteristics of Nb/Au/YBa2Cu3Ox were evidence of the Josephson effect in these heterojunctions. The experimental results are analyzed in terms of the model of the arising of bound states caused by Andreev reflection in superconductors with d-type symmetry of the superconducting order parameter. 相似文献
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Y. V. Kislinskii K. Y. Konstantinian G. A. Ovsyannikov P. V. Komissinskiy I. V. Borisenko A. V. Shadrin 《Journal of Experimental and Theoretical Physics》2008,106(4):800-805
The superconducting current in hybrid superconducting structures Nb/Au/Ca1?x Sr x CuO2/YBa2Cu3O7?δ with an antiferromagnetic layer is experimentally shown to have a Josephson nature, and the deviation from the sinusoidal dependence of the superconducting current on the phase difference between superconducting electrodes is about 20% of the second harmonic. These heterostructures are found to have sensitivity to an applied magnetic field that is much higher than that of conventional Josephson junctions. The experimental shape of the magnetic-field dependence of the critical current in the heterostructures differs from the usual Fraunhofer shape by oscillation with a significantly smaller period along a magnetic field. 相似文献
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Seven 1-, 1,3-, and 2,5- derivatives are used to determine the characteristic frequencies of the bicyclic nucleus and some characteristic frequencies of the endo and exo isomers. Cyclic and aliphatic radicals are found to be present.M. S. Lentovskaya assisted in the experimental work.We are indebted to Professor M.M. Kusakov for interest in this work. 相似文献
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