Tunnel Magnetoresistance In Magnetic Tunnel Junctions With Fealsi Electrode

(001)-oriented FeAlSi polycrystalline thin films with a flat surface and B2-ordered structure were grown on thermally oxidized SiO2 substrates using MgO buffer layers. The FeAlSi thin films composition-adjusted to the Sendust alloy exhibited a low coercivity (H-c) after the annealing process. We utilized these films as bottom electrodes of magnetic tunnel junctions (MTJs) and characterized their tunnel magnetoresistance (TMR) effect. The TMR effect was 35.9% at room temperature. In addition, the TMR ratio increased to 51.0% when a thin CoFeB layer was inserted into the FeAlSi/MgO interface, without degrading the small switching field of the FeAlSi electrode. These MTJs with a small switching field and relatively high TMR ratio using the FeAlSi electrode are promising for highly sensitive MTJ-based magnetic sensor devices.