Magnetic and magnetoresistive properties of cubic Laves phase HoAl$_2$ single crystal

TL;DR

This study investigates the anisotropic magnetic and magnetoresistive properties of HoAl$_2$ single crystals, revealing significant anisotropy, spin reorientation effects, and a theoretical model describing magnetocaloric behavior.

Contribution

It provides new insights into the anisotropic magnetic behavior and magnetocaloric effects in cubic HoAl$_2$ single crystals, supported by experimental results and Landau theory modeling.

Findings

Large anisotropy in magnetization and MR below T_C

Correlation between magnetic entropy change and MR along specific directions

Observation of inverse magnetocaloric effect linked to spin reorientation

Abstract

We report the magnetization ($M$) and magnetoresistance (MR) results of HoAl$_2$ single crystals oriented along $<100>$ and $<110>$ directions. Although HoAl$_2$ has cubic Laves phase structure, a large anisotropy is observed in $M$ and MR results below Curie temperature ($T_C$) at 31.5 K. A satisfactory correlation between magnetic entropy change ($\Delta S_M$) and MR could be established along $<110>$ direction and in $<100>$ direction except for the temperature ($T$) region, around which spin reorientation takes place. Large inverse magnetocaloric effect is observed at low-$T$ which is associated with the spin reorientation process in $<100>$ direction. A theoretical model based on Landau theory of phase transition can describe $T$-variation of -$\Delta S_M$ for $T > T_C$.