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

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-δ (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, Icn, of the micro-bridge is 80 mA, the critical current, IcP, through the micro-bridge when injected from the CMR layer is 38 mA. This clearly shows that spin-polarized quasi particles injected from the CMR layer into the YBCO layer suppress the critical current of the superconductor via the pair- breaking phenomena. (author)