Metastability and magnetic memory effect in Ni-Mn-Sn alloy

TL;DR

This paper investigates the magneto-structural instability and magnetic memory effects in Ni-Mn-Sn alloy, revealing a field-induced arrested state that retains memory of the highest magnetic field applied, linked to martensitic transition behavior.

Contribution

It demonstrates the existence of a magnetic memory effect in Ni-Mn-Sn alloy due to field-induced structural transitions and irreversibility explained by a Landau-type free energy model.

Findings

Large negative magnetoresistance near martensitic transition

Field-induced arrested state with memory of maximum applied field

Irreversibility explained by first order phase transition model

Abstract

Magneto-structural instability in the ferromagnetic shape memory alloy of composition Ni$_2$Mn$_{1.4}$Sn$_{0.6}$ is investigated by transport and magnetic measurements. Large negative magnetoresistance is observed around the martensitic transition temperature (90-210 K). Both magnetization and magnetoresistance data indicate that upon the application of an external magnetic field at a constant temperature, the sample attains a field-induced arrested state which persists even when the field is withdrawn. We observe an intriguing behavior of the arrested state that it can remember the last highest field it has experienced. The field-induced structural transition plays the key role for the observed anomaly and the observed irreversibility can be accounted by the Landau-type free energy model for the first order phase transition.