Semiconducting nature, magnetic critical exponent, and magnetocaloric effect study near room temperature on Fe[sbnd]Mn[sbnd]Al alloy

Abstract

The Fe2.5Mn0.5Al Heusler alloy, prepared by Arc melting method, crystallizes to B2 in the Fm-3m space group. Resistivity measurement shows semi-metallic behavior in low temperature due to the dominance of magnon-magnon scattering and, exhibits semiconducting nature above the Curie temperature. Hence, it is predicted that there is a correlation between magnetic ordering and electrical transport properties. Arrott plot, Kouvel fisher method, and Widom scaling relation have been used here to determine the critical exponents. The Curie temperature (TC) is found to be near room temperature at 280 K. Also, critical exponents indicate that the magnetic ordering is following mean-field theory i.e., long-range interaction is present with 2nd order para to ferromagnetic transition. On the other hand, due to the 2nd order magnetic phase transition, significant magnetocaloric effect has been observed in a wide temperature range near room temperature. The maximum entropy change is found at 280 K i.e., at Tc.