Phase separation and effect of strain on magnetic properties of Mn$_3$Ga$_{1-x}$Sn$_x$C

TL;DR

This study investigates how phase separation and strain influence the magnetic properties of Mn3Ga1-xSnxC compounds, revealing local structural variations affect magnetic behavior despite a cubic global structure.

Contribution

It uncovers the role of local clustering and strain effects in determining magnetic properties in Mn3Ga1-xSnxC, a novel insight into their structure-property relationship.

Findings

Formation of Ga-rich and Sn-rich clusters affects magnetic behavior.

Local environments of Mn atoms vary despite cubic symmetry.

Strain induced by local structure influences magnetic properties.

Abstract

While the unit cell volume of compounds belonging to the Mn$_3$Ga$_{1-x}$Sn$_x$C, (0 $ \le x \le $ 1) series shows a conformity with Vegard's law, their magnetic and magnetocaloric properties behave differently from those of parent compounds Mn$_3$GaC and Mn$_3$SnC. A correlation between the observed magnetic properties and underlying magnetic and local structure suggests that replacing Ga atoms by larger atoms of Sn results in the formation of Ga-rich and Sn-rich clusters. As a result, even though the long range structure appears to be cubic, Mn atoms find themselves in two different local environments. The packing of these two different local structures into a single global structure induces tensile/compressive strains on the Mn$_{6}$C functional unit and is responsible for the observed magnetic properties across the entire solid solution range.