Temperature and magnetic field dependences of the elastic constants of Ni-Mn-Al magnetic Heusler alloys

TL;DR

This study investigates how temperature and magnetic fields influence the elastic constants of Ni-Mn-Al Heusler alloys, revealing anomalies near magnetic transitions and evidence of magnetoelastic coupling.

Contribution

It provides the first detailed measurements of elastic constants across magnetic transitions in Ni-Mn-Al alloys, highlighting magnetoelastic interactions.

Findings

Elastic constants show anomalies near magnetic phase transition.

Elastic constants depend on magnetic order, indicating magnetoelastic coupling.

Magnetic field influences elastic properties both isothermally and with temperature variation.

Abstract

We report on measurements of the adiabatic second order elastic constants of the off-stoichiometric Ni$_{54}$Mn$_{23}$Al$_{23}$ single crystalline Heusler alloy. The variation in the temperature dependence of the elastic constants has been investigated across the magnetic transition and over a broad temperature range. Anomalies in the temperature behaviour of the elastic constants have been found in the vicinity of the magnetic phase transition. Measurements under applied magnetic field, both isothermal and variable temperature, show that the value of the elastic constants depends on magnetic order, thus giving evidence for magnetoelastic coupling in this alloy system.