Effect of Fe substitution on the phase stability and magnetic properties of Mn-rich NiMnGa ferromagnetic shape memory alloys

Abstract

The influence of Fe additions on the martensitic transformation and magnetic properties of Mn-rich NiMnGa alloys was investigated by substituting either 1 at% Fe for each atomic species or by substituting Ni with varying amounts of Fe. The magnetic structure of the alloys was studied using 57Fe Mssbauer spectroscopy. Mssbauer spectra revealed typical paramagnetic features in Mn-rich NiMnGaFe alloys owing to the preferential site occupancy of Fe atoms at Ni sites. The evolution of the magnetic properties and phase stability has been correlated with the chemical and atomic ordering in these alloys. © 2010 Elsevier B.V. All rights reserved.