Effect of Co on magnetic property and phase stability of Ni–Mn–Ga ferromagnetic shape memory alloys: A first-principles study

The effect of Co content on magnetic property and phase stability of Ni_50-xMn₂₅Ga₂₅Co_x ferromagnetic shape memory alloys has been investigated using first-principles calculations. The total energy difference between paramagnetic and ferromagnetic state of austenite plays an important role in the magnetic transition. The high Curie temperature can be attributed to the stronger Co–Mn exchange interaction as compared to the Ni–Mn one. The phase stability of Ni_50-xMn₂₅Ga₂₅Co_x austenite increases with increasing Co content, which is discussed based on the electronic structure.