Magnetic properties of as casted Ni2CrAl Heusler alloy

Abstract

We investigate magnetic properties of as casted Ni2CrAl full-Heusler alloy prepared by arc melting. The Rietveld refinement of x-ray diffraction pattern confirms the cubic L21 phase with B2 disorder, fitted with the space group Fm-3m (no. 225). We use energy dispersive x-ray measurement and elemental mapping to find the stoichiometric ratio and homogeneity of the sample, respectively. The thermomagnetization (M-T) measurements at two different magnetic fields (at 500 Oe and 10 kOe) in the different temperature ranges show short-range magnetic ordering at low temperatures. The dc susceptibility (χ) curve is fitted with the modified Curie-Weiss law and Curie-Weiss (θCW) temperature is found to be -1.62 K. The value of effective magnetic moment (μeff) is estimated to be 0.8 µB/f.u. The bifurcation between zero-field-cooled and field-cooled (ZFC-FC) curves vanishes after applying 10 kOe magnetic fields. Moreover, the Arrott plots of magnetic isotherms (M-H) at various temperatures, up to 70 kOe magnetic field confirm the absence of spontaneous magnetization and no trace of magnetic hysteresis found with absence of remanence and coercivity even at low temperature suggests the presence of superparamagnetic (SPM) entity with paramagnetic (PM) lattices. Therefore, we extract the existence of SPM clusters with the PM lattices at 300 K by fitting the virgin curve with a modified Langevin function.