Tuning the magnetism of the Heusler alloys Mn3-xCoxGa from soft and half-metallic to hard-magnetic for spin-transfer torque applications

The magnetic properties of Mn3-xCoxGa Heusler alloys exhibit a very interesting feature. While the Mn-rich alloys (x = 0.1-0.4) are similar to Mn3Ga as they crystallize in a tetragonally distorted variation of the Heusler structure and exhibit comparable hard-ferrimagnetic properties highly useful for spin-transfer torque applications, the Co-rich samples (x = 0.6-1) exhibit cubic Heusler structures, have soft-magnetic hysteresis loops, and follow the generalized Slater-Pauling curve indicating half-metallic ferrimagnetism. The Curie temperatures of all alloys are above 700 K allowing for high operating temperatures. (C) 2011 American Institute of Physics. [doi:10.1063/1.3665260]