Superconductivity-induced magnetization depletion in a ferromagnet through an insulator in a ferromagnet-insulator-superconductor hybrid oxide heterostructure

• Published in: Nanoscale Vol. 8; no. 19; pp. 1188 - 1197
• Main Authors: Prajapat, C. L, Singh, Surendra, Paul, Amitesh, Bhattacharya, D, Singh, M. R, Mattauch, S, Ravikumar, G, Basu, S
• Format: Journal Article
• Language: English
• Published: England 21.05.2016
• Subjects: Coupling; CRYSTAL GROWTH; ELECTRICAL CONDUCTIVITY; EPITAXY; Ferromagnetism; Heterostructures; INSULATION (ELECTRICAL); Insulators; MAGNETIC PROPERTIES; Magnetization; MAGNETS; OXIDES; SUPERCONDUCTIVITY; SUPERCONDUCTORS; YBCO superconductors
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/c6nr01869f

Coupling between superconducting and ferromagnetic states in hybrid oxide heterostructures is presently a topic of intense research. Such a coupling is due to the leakage of the Cooper pairs into the ferromagnet. However, tunneling of the Cooper pairs though an insulator was never considered plausible. Using depth sensitive polarized neutron reflectivity we demonstrate the coupling between superconductor and magnetic layers in epitaxial La 2/3 Ca 1/3 MnO 3 (LCMO)/SrTiO 3 /YBa 2 Cu 3 O 7− δ (YBCO) hybrid heterostructures, with SrTiO 3 as an intervening oxide insulator layer between the ferromagnet and the superconductor. Measurements above and below the superconducting transition temperature ( T SC ) of YBCO demonstrate a large modulation of magnetization in the ferromagnetic layer below the T SC of YBCO in these heterostructures. This work highlights a unique tunneling phenomenon between the epitaxial layers of an oxide superconductor (YBCO) and a magnetic layer (LCMO) through an insulating layer. Our work would inspire further investigations on the fundamental aspect of a long range order of the triplet spin-pairing in hybrid structures. Magnetization depletion in La 2/3 Ca 1/3 MnO 3 (LCMO) layers as a result of tunneling of Cooper pairs across an insulator SrTiO 3 (STO) in LCMO/STO/YBa 2 Cu 3 O 7− δ (YBCO) heterostructures.