Spin-dependent transport in La0.67Sr0.33MnO3/YBa2Cu3O7-delta junctions

Transport properties across the interface between a ferromagnet and a high- T-c superconductor are studied in La0.67Sr0.33MnO3/YBa2Cu3O7-delta (LSMO/YB CO) junctions. We observed magnetic-field response of conductance spectra p eculiar to LSMO/YBCO junctions, i.e,, increase of background conductance an d asymmetric zero-bias conductance peak splitting. It is shown that these f eatures are consistent with a theory which assumes the presence of a ferrom agnetic insulating layer between a spin-polarized ferromagnet and a d-wave superconductor. (C) 2000 Elsevier Science B.V. All rights reserved.