Effect of short-range order on magnetic and transport properties of Fe2MnGa Heusler alloy films

Fe56Mn20Ga24, Fe46Mn35Ga19 and Fe39Mn25Ga36 Heusler alloy (HA) films are investigated. It is shown that as-deposited Fe-Mn-Ga films are fine crystalline with a body-centered cubic (BCC) structure. Annealing of the films leads to the formation of a face-centered cubic (FCC) structure. The BCC to FCC transformation results in a drastic increase in the magnetization, the Curie temperature as well as in a change of the sign of temperature coefficient of resistivity from negative to positive. These effects are discussed in terms of band structures of L21 and L12 phases of stoichiometric Fe2MnGa HA.