Effect of ball milling and post annealing on structural and magnetic properties in Ni50Mn36Fe2Sb12 Heusler alloy

TL;DR

This study investigates how ball milling and annealing affect the structural and magnetic properties of Ni50Mn36Fe2Sb12 Heusler alloys, revealing phase coexistence, grain size reduction, and changes in magnetic behavior.

Contribution

It provides new insights into the effects of mechanical milling and thermal treatment on phase composition and magnetic properties of Ni-Mn-Fe-Sb Heusler alloys.

Findings

Ball milling induces phase coexistence at room temperature.

Annealing suppresses the austenite phase.

Milling reduces grain size and weakens ferromagnetism.

Abstract

The effect of ball milling on the structural, magnetic and exchange bias properties of Ni50Mn36Fe2Sb12 Heusler alloys was studied. The ball milled samples exhibited coexisting austenite and martensite phases at room temperature, while annealing supresses the austenite phase completely. Ball milling was found to reduce the grain size, which resulted in the weakening of the ferromagnetic properties. An exchange bias field of 111 Oe and coercivity of 826 Oe were observed at 5 K in the as-milled sample, in contrast to the bulk alloy values of 288 Oe and 292 Oe, respectively. Annealing causes an increase in the ferromagnetic ordering and a decrease in the interfacial exchange coupling, resulting in a decrease of both exchange bias and coercivity.