Temperature and voltage dependence of magnetic barrier junctions with a nonmagnetic spacer

Abstract

The temperature and voltage dependence of spin transport is theoretically investigated in a new type of magnetic tunnel junction, which consists of two ferromagnetic outer electrodes separated by a ferromagnetic barrier and a nonmagnetic (NM) metallic spacer. The effect of spin fluctuation in magnetic barrier, which plays an important role at finite temperature, is included by taking the mean-field approximation. It is found that, the tunnel magnetoresistance (TMR) and the electron-spin polarization depend strongly on the temperature and the applied voltage. The TMR and spin polarization at different temperatures show an oscillatory behavior as a function of the NM spacer thickness. Also, the amplitude of these oscillations is regularly reduced when the temperature increases. The maximum TMR value, varies approximately from 270% in reverse bias (at $T$=0 K) to 25% in forward bias (at $T\geq T_C$).