Magnetic properties and stability of L21 and B2 phases in the Co2MnAl Heusler alloy

Magnetic properties and stability of L2(1) and B2 phases in the Co2MnAl Heusler alloy were investigated. It was confirmed that the order-disorder transition from the B2 to L2(1) phase is located at about 950 K and that the Curie temperature T-C of the L2(1) phase is 726 K which is about 50 K higher than that (T-C=677 K) of the B2 phase. The difference in T-C between the L2(1) and B2 phases is smaller than a theoretical prediction. On the other hand, the saturation magnetic moments M-s at 4.2 K for the L2(1) and B2 phases were estimated to be 4.07 mu(B)/f.u. and 4.16 mu(B)/f.u., respectively, comparable to the value M-t=4 expected from the generalized Slater-Pauling relation. (C) 2008 American Institute of Physics.