Intrinsic spin filtering in a / junctionY. F. Chen and M. Ziese
Division of Superconductivity and Magnetism, Faculty of Physics and Geosciences, University of Leipzig 04103 Leipzig, Germany
received 20 October 2006; accepted in final form 12 December 2006; published February 2007
published online 1 February 2007
The nonlinear transport properties and the magnetoresistance of a junction between La2/3Ca1/3MnO3 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.
72.25.-b - Spin polarized transport.
72.25.Mk - Spin transport through interfaces.
75.47.Gk - Colossal magnetoresistance.
© Europhysics Letters Association 2007