Temperature and bias voltage dependence of tunnel magnetoresistance effect in magnetic tunnel junctions with Co₂Fe(Al,Si) electrodes fabricated by MBE

The temperature and bias voltage dependence of tunnel magnetoresistance ratio of two types of magnetic tunnel junctions were investigated. These two types of junctions have almost the same ordered structured Co ₂FeAl_0.5Si_0.5 Heusler bottom electrodes and different barrier layers of Al oxide or MgO, and top electrodes. A similar temperature dependence of tunnel magnetoresistance ratio measured at low bias voltage was found. A larger asymmetric bias voltage dependence of the tunnel magnetoresistance was obtained for the junction with Al oxide barrier compared with the junction with MgO barrier, and negative tunnel magnetoresistance ratio was also observed for both junctions.