Tunnel magnetoresistance in magnetic tunnel junctions with Co2Fe (Al, Si) full-Heusler films

Abstract The magnetoresistance effect for a magnetic tunnel junction (MTJ) with Co 2 FeAl 0.5 Si 0.5 electrodes on Cr buffered MgO (0 0 1) substrate has been investigated. The MTJ with B2-type Co 2 FeAl 0.5 Si 0.5 electrode exhibited tunnel magnetoresistance (TMR) ratio of 76% at room temperature (RT) and 106% at 5 K, while that with L2 1 structure showed 51% and 78% at RT and 5 K, respectively. For both cases, the bias voltage dependence of TMR ratio is almost the same, but only for the MTJs with a Co 2 FeAl 0.5 Si 0.5 electrode annealed at 600 °C shows a dip around −200 mV.