Phase stability and magnetic properties of L21 phase in Co2Mn(Al1−Si ) Heusler alloys

The phase stability and magnetic properties of the L 2 1 phase in Co 2 Mn(Al 1− x Si x ) Heusler alloys were investigated. The order–disorder phase transition temperature, T t L 2 1 / B 2 , increases linearly with increasing x ; T t L 2 1 / B 2 for Co 2 MnSi is estimated to be about 1580 K. These results mean that the stability of L 2 1 phase of Co 2 MnSi is much higher than that of Co 2 MnAl. Although the saturation magnetic moment increases linearly with increasing x , i.e., consistent with the generalized Slater–Pauling behavior, the Curie temperature increases, exhibiting slightly upward convexity.