Effect of Co substitution on magnetic properties of NinMn–Sn magnetic shape memory alloys

The effect of Co substitution on magnetic properties of NinMn–Sn shape memory alloy was revealed by first-principles calculations. Large magnetization difference in NinMn–Sn alloy obtained by addition of Co arises from enhancement of magnetization of austenite due to change of Mn-Mn interaction from anti-ferromagnetism to ferromagnetism. Total energy difference between paramagnetic and ferromagnetic austenite plays an important role in magnetic transition of Ni–Co–Mn–Sn. The altered Mn 3d states due to Co substitution give rise to difference in magnetic properties.