Probing magnetic-field-induced multipolar ordering through field-angle-resolved magnetostriction and thermal expansion in PrIr$_2$Zn$_{20}$

TL;DR

This study investigates how magnetic field orientation influences multipolar ordering in PrIr$_2$Zn$_{20}$ using magnetostriction and thermal expansion measurements, revealing anisotropic quadrupolar interactions and an intermediate phase.

Contribution

It provides experimental evidence and theoretical analysis of field-angle-dependent multipolar states in a non-Kramers compound, highlighting the role of anisotropic quadrupolar coupling.

Findings

Identification of two distinct anomalies in thermal expansion under magnetic fields.

Experimental support for the existence of an intermediate A phase.

Strong anisotropic coupling of the $O_{20}$ quadrupolar moment stabilizes the A phase.

Abstract

We performed field-angle-resolved magnetostriction and thermal-expansion measurements on PrIr$_2$Zn$_{20}$, a cubic non-Kramers compound exhibiting antiferroquadrupolar order below $T_{\rm Q}=0.125$ K. Thermal expansion exhibits two qualitatively different anomalies under magnetic fields applied along the $[001]$ direction, providing experimental support for the existence of an intermediate A phase previously reported. Furthermore, comparison between the experimental results and theoretical modeling indicates a strong anisotropic coupling of the $O_{20}$ quadrupolar moment, which plays a key role in stabilizing the A phase. These findings demonstrate that multipolar states in non-Kramers systems can be effectively tuned by magnetic-field orientation, providing insights into the anisotropic nature of quadrupolar interactions.