Effect of composition on magnetocaloric properties of Mn$ _{3} $Ga$ _{(1-x)} $Sn$ _{x} $C

TL;DR

This study explores how substituting Sn for Ga in Mn3GaC affects its magnetocaloric effect, revealing a transition from inverse to conventional MCE depending on Sn concentration and highlighting the role of local strain in magnetostructural coupling.

Contribution

It demonstrates the impact of Sn substitution on the magnetocaloric properties and elucidates the role of local strain in tuning the magnetic and structural transitions.

Findings

Inverse MCE observed at low Sn content ($ x extless=0.2 $).

Transition to conventional MCE at high Sn content ($ x extgreater=0.71 $).

Local strain influences magnetostructural coupling.

Abstract

A study investigating the effect of Sn substitution on the magnetocaloric properties of Mn$ _{3} $Ga$ _{(1-x)} $Sn$ _{x} $C compounds reveals that nature of the MCE has a strong dependence on the nature of the magnetic ordering. For small amounts of Sn ($ x\leq0.2 $) the MCE is of the inverse type wherein an increase in the applied field beyond 5T gives rise to a table like temperature dependence of the entropy due to a coupling between the first order FM - AFM transition and the field induced AFM - FM transition. Replacement of Ga by larger concentrations of Sn ($ x\geq0.71 $) $(\Delta S_M)$ results in a change of the MCE to a conventional type with very little variation in the position of $(\Delta S_M)_{max}$ with increasing magnetic field. This has been explained to be due to the local strain introduced by A site ions (Ga/Sn) which affect the magnetostructural coupling in these compounds.