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

TL;DR

This paper theoretically investigates how temperature and voltage influence spin transport in a novel magnetic tunnel junction with a nonmagnetic spacer, revealing oscillatory behaviors and TMR variations with temperature and bias.

Contribution

It introduces a theoretical model for magnetic tunnel junctions with a nonmagnetic spacer, including spin fluctuations, and analyzes their temperature and voltage dependence.

Findings

TMR and spin polarization depend strongly on temperature and voltage.

Oscillatory behavior of TMR and spin polarization with spacer thickness.

Maximum TMR decreases from 270% at 0 K to 25% at high temperatures.

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 $T\geq T_C$).