In search for new ferromagnetic shape memory alloys (FSMA) we have calculated structural energy diơerences, magnetic exchange interaction constants and mixing energies of quaternary (X 1 X 2 )YZ Heusler alloys with X 1 , X 2 , Y = Ni, Co, Fe and Z = Ga, Zn using density functional theory. The comparison of the energy pro¿les of (NiCo)FeZ, (FeNi)CoZ, and (FeCo)NiZ with Z = Ga and Zn as a function of the tetragonal distortion c/a reveals that the energetically preferred ordering type is

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... and (NiCo)FeZn which shows that Fe prefers to occupy the same cubic sublattice as Ga or Zn what implies that Fe favors Co and Ni as nearest neighbors, respectively. The Curie temperatures of (NiCo)FeGa and (NiCo)FeZn are high of the order of 600 K. NiCo)FeGa, which has the same valence electron concentration (e/a = 7.5) as Ni 2 MnGa and also possesses a high martensitic ransformation temperature (> 500 K), is of interest for future magnetic shape memory devices. ( t PACS: 71.15 Nc; 61.66 Dk; 71.15 Mb; 71.15 Pd; Keywords: ferromagnetic shape memory alloys; electronic properties; ab initio calculations; ȗ Ǧ͵ͷͶǢ ǣ ΪͶͻǦʹͲ͵Ǧ͵ͻǦ͵ͷǤ Ǥ Ǥǣ ΪͶͻǦʹͲ͵Ǧ͵ͻ EǦmail addressǣ ̷ǤǦǤ c ⃝