Effect of addition of Co on the magnetic properties of MnSb

Abstract

The influence of addition of Co on the structural and magnetic properties of MnSb was investigated. The compound formed in the NiAs-type hexagonal structure. Addition of Co to MnSb causes changes in both the lattice parameters. It was observed, from magnetization measurements, that both Curie temperature and saturation magnetization decrease from those of MnSb. The spin-polarized density of states (DOS) calculations revealed that the intermetallic compound favors ferromagnetic ground state even after as much as 0.25 atom of Co per formula unit of MnSb. Charge transfer takes place from the interstitial Co-atom to minority spin band of Mn-atom resulting in an increase in the DOS compared to MnSb at the Fermi level. MnSbCo0.25 exhibits a negative magnetocaloric effect with the largest change in the entropy value, ΔSm = 2.5 J. kg-1. K-1 (for a change in magnetic field from 0 to 5 T), across the second order phase transition at 292 K. The change in the value of magnetic entropy is low around the phase transition and might be due to the small magnetic moment of Mn-atom.