Structure and magnetic properties of low-temperature annealed Ni-Mn-Al alloys

Abstract

Off-stoichiometric Ni2Mn2-xAlx (x = 0.5-1.2) and Ni2+y(Mn1.3Al0.7)(1-y/2), (y = 0.04-0.12) alloys were prepared to locate the composition range which is likely to form the ferromagnetic ordered L2(1) phase through low-temperature thermal annealing. In the Ni2Mn2-xAlx (x = 0.5-1.2) series, the alloy partially transformed to the ferromagnetic phase in the narrow composition range of x = 0.8-1.1. For the Ni-enriched composition series, Ni2+y(Mn1.3Al0.7)(1-y/2), (y = 0.04-0.12), magnetic ordering was not observed and the magnetic susceptibility proportionally decreased with the Ni concentration. It was concluded that moving away from stoichiometric composition would likely increase the disordering of Mn and Al site occupation and is not conducive to achieving ferromagnetism in Ni2MnAl. (C) 2013 American Institute of Physics.