Effect of Si and Ga substitutions on the magnetocaloric properties of NiCoMnSb quaternary Heusler alloys

TL;DR

This study investigates how Si and Ga substitutions affect the magnetic and magnetocaloric properties of NiCoMnSb Heusler alloys, revealing phase stabilization effects and significant magnetocaloric effects with potential applications.

Contribution

It provides new insights into how Si and Ga substitutions influence phase stability and magnetocaloric properties in NiCoMnSb Heusler alloys.

Findings

Si stabilizes the austenite phase, Ga stabilizes the martensite phase.

Large magnetocaloric effect observed for Si substitutions.

Ga substitutions produce broader MCE peaks despite lower maximum values.

Abstract

The effect of Si and Ga substitutions on the magnetic and the magnetocaloric properties in Heusler based system Ni46Co4Mn38Sb12-xZx (Z=Si and Ga) has been studied. From the M(T) plots it is found that Si substitution stabilizes the austenite phase, whereas, Ga substitution stabilizes the martensite phase. Strong metamagnetic behaviour is observed in the M(H) isotherms for Si=0.75 and 1, whereas, such a behaviour is absent in the Ga substituted alloys. Associated with magneto-structural transition, large MCE of 58 J/kg K and 70 J/kg K is observed for x=0.75 and 1, respectively in the case of Si. Though the MCE observed in x=0.5 and 1 in the case of Ga is much lower, the MCE peak is found to be quite broad.