Direct injection of spin-polarized carriers across YBa2Cu3O7-delta-La0.3Ca0.7MnO3 interface at 77 K

Abstract

We report here injection of spin-polarized carriers from a half-metallic La0.3Ca0.7MnO3 (LCMO) colossal magnetoresistive (CMR) thin film into a high-temperature superconducting YBa2Cu3O7-delta (YBCO) thin film studied using a micro-bridge. The LCMO and YBCO films were grown on <100> LaAlO3 (LAO) substrate sequentially using pulsed laser deposition (PLD). I-V measurements carried out at 77 K show that while normal critical current, l(c)(n), of the micro-bridge is 80 mA, the critical current, l(c)(p), through the micro-bridge when injected from the CMR layer is 38 mA. This clearly shows that spin-polarized quasiparticles injected from the CMR layer into the YBCO layer suppress the critical current of the superconductor via the pair-breaking phenomena.