Magnetic anisotropy in HoIr$_2$Si$_2$ ($I4/mmm$)

TL;DR

This study reports the synthesis, structural characterization, and magnetic properties of HoIr$_2$Si$_2$ single crystals, revealing strong magnetic anisotropy and crystalline electric field effects in this compound.

Contribution

The paper provides detailed structural and magnetic analysis of HoIr$_2$Si$_2$, including growth method, structure determination, and magnetic anisotropy measurements, which are novel for this compound.

Findings

Neel temperature of 22 K identified

Strong magnetic anisotropy observed in susceptibility

Crystalline electric field effects cause step-like magnetization

Abstract

Single crystals of HoIr$_2$Si$_2$ with the body-centered ThCr$_2$Si$_2$-type structure ($I4/mmm$) were grown by Bridgman method from indium flux. Single crystal structure determination yielded a Si-z position of 0.378(1) in the structure. We excluded the presence of the high temperature phase with the primitive CaBe$_2$Ge$_2$-type structure ($P 4/n m m$) by powder X-ray diffraction. Magnetic measurements on the single crystals yield a Neel temperature of $T_{\rm N}=22\,\rm K$. In the inverse magnetic susceptibility a strong anisotropy with Weiss temperatures $\Theta_{W}^{001}=26\,\rm K$ and $\Theta_{W}^{100}=-26\,\rm K$ occurs above $T_{\rm N}$. The effective magnetic moment $\mu_{\rm eff}^{001}=10.64\mu_{B}$ and $\mu_{\rm eff}^{100}=10.53\mu_{B}$ is close to the expected value for a free Ho$^{3+}$ ion, $\mu_{\rm eff}^{calc}=10.6\mu_{B}$. The field dependent magnetization shows a step-like behaviour due to crystalline electric field effects.