Tunnel magnetoresistance in textured Co 2 FeAl / MgO / CoFe magnetic tunnel junctions on a Si / SiO 2 amorphous substrate

Magnetic tunnel junctions with B 2 -ordered Co 2 FeAl full Heusler alloy as a ferromagnetic electrode were fabricated by sputtering on thermally oxidized Si / SiO 2 amorphous substrates. A Co 2 FeAl / MgO / Co 50 Fe 50 structure showed a highly (001)-textured structure and the tunneling magnetoresistance (TMR) ratio of 166% at room temperature and 252% at 48 K were achieved. The temperature dependence of TMR can be fitted with spin wave excitation model, and the bias voltage dependence of differential conductance demonstrated that the high TMR was mainly contributed by coherent tunneling. This work suggests the B 2 -Co 2 FeAl is one of the promising candidates for practical spintronic applications.