Ni-Mn-X Heusler materials

Abstract

In this chapter, the order-disorder phase transformation from the B2 to the L21-type phase and magnetic properties of Ni2Mn(GaxAl1-x) and Ni2Mn1+yIn1-y alloys are introduced, and the influence of martensitic transformation on the magnetic properties in NiMnIn-based alloy is also discussed. The magnetic properties of these alloys are significantly sensitive to the degree of long-range order, the alloy composition, and the crystal structure, and themagnetism varies among paramagnetic, ferromagnetic, and antiferromagnetic properties, in dependence on these factors. On the whole, the magnetic properties are mainly governed by the magnetic moments of Mn atoms and can be understood by taking into account the sign and the strength of the magnetic exchange interactions in Mn-Mn and Ni-Mn pairs. © Springer-Verlag Berlin Heidelberg 2012.