The influence of partial substitution of Bi for Sb on the structure, magnetic properties and magnetocaloric effect of Mn2Sb1-xBix (x = 0, 0.02, 0.04, 0.05, 0.07, 0.09, 0.15, 0.20) compounds has been investigated. The transition temperature of the antiferro-to-ferrimagnetic (AFM-FIM) transition initially increases with increasing Bi and decreases above 9%. Density functional theory calculations indicate that the Bi atoms prefer to occupy only the Sb site, which accounts for the large magnetization jump in Mn2Sb0.93Bi0.07. As large lattice parameters are found for Bi substituted Mn2Sb, the origin of the AFM-FIM transition in Mn2Sb(1-x)Bix compounds is ascribed to an enhanced coefficient of thermal expansion along the c axis, resulting from the Bi substitution. The moderate entropy change of 1.17 J/kg K under 2 T originating from the inverse magnetocaloric effect and the strong magnetic field dependence of the transition temperature of dTt/dµ0H = −5.4 K/T in Mn2Sb0.95Bi0.05 indicate that this alloy is a promising candidate material for magnetocaloric applications.
- Antiferro-to-ferrimagnetic phase transition
- Exchange inversion
- Inverse magnetocaloric effect