Gradual phase transition from ferromagnetic tetragonal to antiferromagnetic cubic states in Mn x Ga (1.80 ≤ x ≤ 3.03) thin films

The structural, magnetic, and electronic properties of Mn_xGa thin films are investigated as varying the Mn composition (1.80 ≤ x ≤ 3.03). The variation of x in Mn_xGa films dramatically changes the crystal structure as well as the magnetic properties. With increasing x, we observe the gradual phase transition from a ferromagnetic tetragonal state to an antiferromagnetic cubic state. The structural characterization reveals that the D0₂₂ tetragonal structure of Mn₂Ga is slowly transformed to the L1₂ cubic structure of Mn₃Ga. Two phases coexist around x = 2.4. The magnetization is systematically reduced as x increases, ending to an antiferromagnetic state of cubic Mn₃Ga, and the electrical resistivity increases with x. Such highly tunable magnetic and electronic properties in Mn_xGa phase simply by the variation of the Mn/Ga ratio provide advantages to be used for spintronic device applications.