Phase evaluation, magnetic, and electric properties of Mn60+xGa40−x (x = 0–15) ribbons

Mn60+xGa40−x (x = 0, 5, 10, and 15) ribbons were prepared by the melt-spinning technique and subsequently by a heat treatment at 673 K for 1 h. The magnetic phases Mn8Ga5, Mn1.86Ga, D019-Mn3Ga, and D022-Mn3Ga are found to appear in these annealed melt-spun ribbons. The Curie temperature TC of the ribbons varies from 125 K to 185 K as x changes from 0 to 5. For x = 10, the hexagonal structure of the D019-Mn3Ga phase is distorted to an orthorhombic one below the phase transition temperature Td = 185 K. The optimized values for coercivity at room temperature are 0.13, 4.4, 8.1, and 7.7 kOe for the ribbons with x = 0, 5, 10, and 15, respectively. The resistance measurements indicate that the ribbons show a typical metallic behavior for x = 5–15.