DIFFERENTIAL CONDUCTANCE OF THE FERROMAGNET SUPERCONDUCTOR INTERFACE OF DYBA2CU3O7/LA2/3BA1/3MNO3 HETEROSTRUCTURES/

The voltage bias, temperature, and magnetic field dependence of the di fferential conductance of the interface between a half-metallic ferrom agnet and a high-T-c superconductor have been studied in DyBa2Cu3O7/La 2/3Ba1/3MnO3 heterostructures. Below the superconducting transition th e differential conductance exhibits a dip at zero bias whose amplitude is a decreasing function of temperature and/or magnetic field. These results are interpreted qualitatively using a picture based on the sup pression of Andreev reflection as a consequence of the high spin polar ization of the carriers in the half-metallic ferromagnet. (C) 1998 Ame rican Institute of Physics.