Localized Pair Breaking Effect in the Quasi-multilayers of YBa2Cu3O7−δ /La0.88Ca0.12MnO3

Abstract

Quasi-multilayers consisting of superconducting YBa2Cu3O7−δ (YBCO) and ferromagnetic La0.88Ca0.12MnO3 (LCMO), namely p×(YBCO(m)/LCMO(n)) (p: repetition periods, m: YBCO pulse number, and n: LCMO pulse number) are prepared on single crystal LaAlO3 (LAO) by pulsed laser deposition (PLD). X-ray diffraction measurements reveal that both in-plane and out-of-plane textures of the quasi-multilayers are as good as in the pure YBCO films. Nevertheless, the present quasi-multilayer system shows significant modifications in the superconducting properties, as evidenced by the suppressed superconducting transition temperature as well as the critical current density. This indicates that a special pair breaking effect emerges at YBCO/LCMO interfaces, and it is believed to arise from the spin scattering by the local exchange field due to the insulating nature of the ferromagnetic LCMO.