Temperature Dependence of the Spin Tunneling Magnetoresistive Effect on NiFe/Co/Al2O3/Co/NiFe/FeMn Junctions

Abstract
Spin-valve type spin tunneling junctions using contact metal masks have been fabricated. The annealing effect and temperature dependence of the tunneling magnetoresistance (TMR) ratio and saturated resistance (R s) have been investigated. As-prepared NiFe/Co/Al2O3/Co/NiFe/FeMn junctions show a spin-valve like MR curve and a TMR ratio of up to 28% at room temperature. The temperature dependence of the TMR ratio and R s is affected by the annealing. For annealed junction, the TMR ratio slightly decreases with increasing temperature and rapidly decreases around 418 K because of the disappearance of an exchange bias of the FeMn layer.