Spin-polarized transport across a La0.7Sr0.3MnO3/YBa2Cu3O7-x interface: Role of Andreev bound states - art. no. 212508

Transport across an La0.7Sr0.3MnO3 /YBa2Cu3O7-x (LSMO/YBCO) interface is st udied as a function of temperature and surface morphology. For comparison, control measurements are performed in nonmagnetic heterostructures of LaNiO 3/YBCO and Ag/YBCO. In all cases, YBCO is used as bottom layer to eliminate the channel resistance and to minimize thermal effects. The observed diffe rential conductance reflects the role of Andreev bound states in the a-b pl ane, and displays the suppression of such states by the spin-polarized tran sport across the interface. The theoretical analysis of the measured data r eveals decay of the spin polarization near the LSMO surface with temperatur e, consistent with the reported photoemission data.