Unusual Strain glassy phase in Fe doped Ni$_2$Mn$_{1.5}$In$_{0.5}$

TL;DR

This study reveals a strain glassy phase in Fe-doped Ni2Mn1.5In0.5, characterized by frequency-dependent mechanical behavior and ergodicity breaking, caused by non-interacting strain domains despite long-range order signatures.

Contribution

It demonstrates the existence of a strain glassy phase in Fe-doped Ni2Mn1.5In0.5, highlighting the role of Fe impurities in disrupting strain domain interactions.

Findings

Frequency-dependent storage modulus and loss follow Vogel-Fulcher law.

Presence of ergodicity breaking between zero field cooled and field cooled measurements.

Strain domains are large enough to show long-range order but do not interact due to Fe impurities.

Abstract

Fe doped Ni$_2$Mn$_{1.5}$In$_{0.5}$, particularly, Ni$_2$Mn$_{1.4}$Fe$_{0.1}$In$_{0.5}$, despite having an incommensurate, modulated 7M martensitic structure at room temperature exhibits frequency dependent behavior of storage modulus and loss that obeys Vogel-Fulcher law as well as shows ergodicity breaking between zero field cooled and field cooled strain measurements just above the transition temperature. Both, frequency dependence and ergodicity breaking are characteristics of a strain glassy phase and occur due to presence of strain domains which are large enough to present signatures of long range martensitic order in diffraction but are non interacting with other strain domains due to presence of Fe impurity.