Easy-plane magnetocrystalline anisotropy in the multi-step metamagnet CeIr3Si2

TL;DR

This study reveals highly anisotropic magnetic and electronic properties in CeIr3Si2, including multiple magnetic transitions, metamagnetic behavior, and strong crystal field effects, driven by Kondo interactions and crystal field splitting.

Contribution

It provides detailed experimental characterization of CeIr3Si2's anisotropic magnetism and electronic behavior, highlighting its complex interplay of Kondo effect and crystal field splitting.

Findings

Multiple magnetic transitions at 3.9 K and 3.1 K.

Metamagnetic transitions at low fields for different orientations.

Strong crystal field splitting with energy levels at 500 K and 1600 K.

Abstract

Highly anisotropic properties of CeIr$_3$Si$_2$ have been observed by the magnetization $M$($B$), electrical resistivity $\rho$, and specific heat measurements on a single-crystalline sample. This compound with an orthorhombic structure having zigzag chains of Ce ions along the a-axis undergos magnetic transitions at 3.9 K and 3.1 K. At 0.3 K, metamagnetic transitions occur at 0.68 T and 1.3 T for $B$$//$$b$ and 0.75 T for $B$$//$$c$. Easy-plane magnetocrystalline anisotropy is manifested as $M$($B//b$) $\cong$ $M$($B//c$) $\cong$ 11$M$($B//a$) at $B$ = 5 T. Electrical resistivity is also anisotropic; $\rho_{b}$ $\cong$ $\rho_{c}$ $\ge$ 2$\rho_{a}$. The magnetic part of $\rho$ exhibits a double-peak structure with maxima at 15 K and 250 K. The magnetic entropy at $T$$\rm_{N1}$ = 3.9 K is a half of $R$ln2. These observations are ascribable to the combination of the Kondo effect with $T$$\rm_{K}$ $\sim$ 20 K and a strong crystal field effect. The analysis of $M$($B$) and paramagnetic susceptibility revealed unusually large energy splitting of 500 K and 1600 K for the two excited doublets, respectively.