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

The phase stability and magnetic properties of the L21 phase in Co2Mn(Al1−xSix) Heusler alloys were investigated. The order-disorder phase transition temperature, TtL21/B2, increases linearly with increasing x; TtL21/B2 for Co2MnSi is estimated to be about 1580 K. These results mean that the stability of L21 phase of Co2MnSi is much higher than that of Co2MnAl. 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.