The antiferromagnetic to ferrimagnetic phase transition in Mn2Sb1-xBix compounds

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 dT(t)/d(mu 0)H = -5.4 K/T in Mn2Sb0.95Bi0.05 indicate that this alloy is a promising candidate material for magnetocaloric applications. (C) 2021 The Authors. Published by Elsevier B.V.CC_BY_4.0

Automated summary

The impact of partial substitution of Bi for Sb on Mn2Sb1-xBix compounds was investigated, revealing that Bi content affects the antiferro-to-ferrimagnetic transition temperature, and the increase in lattice parameters due to Bi substitution explains the origin of the transition.