EPL 77, 47001 (2007)

Y. F. Chen and M. Ziese

Abstract

The nonlinear transport properties and the magnetoresistance of a junction between La_2/3Ca_1/3MnO₃ and Nb(1.0%)-doped SrTiO₃ were studied. The striking feature in the present magnetoresistance data is the appearance of a step-like magnetoresistance hysteresis that typically occurs in magnetic tunnelling junctions with two ferromagnetic electrodes. This is unexpected, since the structures under study contain only one ferromagnetic layer. Therefore this tunnelling magnetoresistance is attributed to spin filtering by an insulating, but ferromagnetic interfacial layer in this manganite/Nb:SrTiO₃ bilayer system. From the measured values for the tunnelling magnetoresistance the spin polarization of the interfacial layer is derived.