Effect of the main-group elements on the electronic structures and magnetic properties of Heusler alloys Mn2NiZ (Z=In, Sn, Sb)

The magnetic properties and electronic structure of Mn2NiZ (Z=In, Sn, Sb) have been studied. The magnetic structure of these alloys is mainly determined by the main-group element Z instead of the distance between the Mn atoms. Electronic structure calculations suggest that Mn2NiIn and Mn2NiSn are both ferrimagnets with antiparallel alignment between the Mn moments. But this antiferromagnetic coupling is weakened by the increasing number of valence electrons of the Z atoms. When it comes to Mn2NiSb, a ferromagnetic coupling between the Mn atoms is observed. Mn2NiSn and Mn2NiSb have been synthesized successfully. Their Ms at 5 K agree well with the theoretical value.