Magnetic proximity effect at the interface between a cuprate superconductor and an oxide spin valve

• Published in: Journal of experimental and theoretical physics Vol. 122; no. 4; pp. 738 - 747
• Main Authors: Ovsyannikov, G. A., Demidov, V. V., Khaydukov, Yu. N., Mustafa, L., Constantinian, K. Y., Kalabukhov, A. V., Winkler, D.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.04.2016; Springer
• Subjects: BARIUM COMPOUNDS; Classical and Quantum Gravitation; COHERENCE LENGTH; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CUPRATES; DENSITY OF STATES; Electronic Properties of Solid; Elementary Particles; FERROMAGNETIC RESONANCE; Ferromagnetism; HIGH-TC SUPERCONDUCTORS; INTERFACES; LANTHANUM COMPOUNDS; MAGNETIC MOMENTS; MAGNETIZATION; MANGANATES; OXIDES; Particle and Nuclear Physics; PENETRATION DEPTH; Physics; Physics and Astronomy; PROXIMITY EFFECT; Quantum Field Theory; Relativity Theory; RUTHENIUM COMPOUNDS; Solid State Physics; SPIN; SQUID DEVICES; STRONTIUM COMPOUNDS; Superconductors; Valves; YTTRIUM COMPOUNDS; YBCO Film; Ferromagnetic Film; Resonance Field; Cuprate Superconductor; Spin Valve
• ISSN: 1063-7761; 1090-6509; 1090-6509
• DOI: 10.1134/S1063776116040063

A heterostructure that consists of the YBa 2 Cu 3 O 7–δ cuprate superconductor and the SrRuO 3 /La 0.7 Sr 0.3 MnO 3 ruthenate/manganite spin valve is investigated using SQUID magnetometry, ferromagnetic resonance, and neutron reflectometry. It is shown that a magnetic moment is induced due to the magnetic proximity effect in the superconducting part of the heterostructure, while the magnetic moment in the composite ferromagnetic interlayer is suppressed. The magnetization emerging in the superconductor coincides in order of magnitude with the results of calculations taking into account the induced magnetic moment of Cu atoms because of orbital reconstruction at the interface between the superconductor and the ferromagnet, as well as with the results of the model taking into account the variations in the density of states at a distance on the order of the coherence length in the superconductor. The experimentally obtained characteristic penetration depth of the magnetic moment in the superconductor considerably exceeds the coherence length of the cuprate superconductor, which indicates the predominance of the mechanism of induced magnetic moment of Cu atoms.