Reentrant spin glass state in Mn doped Ni2MnSn shape memory alloy

TL;DR

This study investigates the magnetic ground state of Mn-doped Ni2MnSn shape memory alloy, revealing a reentrant spin glass phase coexisting with ferromagnetism at low temperatures, characterized by exchange bias and spin glass freezing.

Contribution

It provides the first detailed experimental evidence of a reentrant spin glass state in Mn-doped Ni2MnSn alloy, linking magnetic anomalies to spin glass behavior.

Findings

Presence of exchange bias originating from the anomaly temperature.

Identification of spin glass freezing through ac susceptibility.

Coexistence of ferromagnetic and glassy phases at low temperature.

Abstract

The ground state properties of the ferromagnetic shape memory alloy of nominal composition Ni2Mn1.36Sn0.64 have been studied by dc magnetization and ac susceptibility measurements. Like few other Ni-Mn based alloys, this sample exhibits exchange bias phenomenon. The observed exchange bias pinning was found to originate right from the temperature where a step-like anomaly is present in the zero-field-cooled magnetization data. The ac susceptibility study indicates the onset of spin glass freezing near this step-like anomaly with clear frequency shift. The sample can be identified as a reentrant spin glass with both ferromagnetic and glassy phases coexisting together at low temperature at least in the field-cooled state. The result provides us an comprehensive view to identify the magnetic character of various Ni-Mn-based shape memory alloys with competing magnetic interactions.