Temperature dependence of the tunneling magnetoresistance and ferromagnetism in Ni65Cu35 magnetic tunnel junctions (Retracted article. See vol. 56, pg. 171, 2010)

Abstract

The temperature dependence of the tunneling magnetoresistance and magnetization have been measured for spin-valve magnetic tunnel junctions in which the pinned magnetic electrodes is a Ni65Cu35 alloy with a Curie temperature of roughly 250 K. By extracting the spin polarization of the NiCu electrode using the Julliere formula, it is shown that the tunneling spin-polarization as a function of temperature can be related to the temperature-dependent magnetization. The observed quasi-linear relation between the magnetization and the tunneling spin polarization is consistent with the theoretical picture of predominantly s-electron tunneling with the spin-polarization arising via hybridization with the exchange split 3d band.