Synthesis and magnetism of single-phase Mn-Ga films

Single-phase noncubic Mn-Ga films with a thickness of about 200 nm were fabricated by an in situ annealing of [Mn(x)/Ga(y)/Mn(x)]₅ multilayers deposited by e-beam evaporation. Mn-Ga alloys prepared in three different compositions Mn₂Ga₅ and Mn₂Ga were found to crystallize in the tetragonal tP14 and tP2 structures, respectively. Mn₃Ga crystallizes in the hexagonal hp8 or tetragonal tI8 structures. All three alloys show substantial magnetocrystalline anisotropy between 7 and 10 Mergs/cm³. The samples show hard magnetic properties including coercivities of Mn₂Ga₅ and Mn₂Ga about 12.0 kOe and of Mn₃Ga about 13.4 kOe. The saturation magnetization and Curie temperature of Mn₂Ga₅, Mn₂Ga, and Mn₃Ga are 183 emu/cm³ and 435 K, 342 emu/cm³ and 697 K, and 151 emu/cm³ and 798 K, respectively. The samples show metallic electron transport up to room temperature