Antiferromagnetism weakening with Y-substitution in the TbRhIn$_5$ intermetallic system

TL;DR

This study investigates how Y-substitution affects antiferromagnetism in TbRhIn$_5$, revealing that dilution and structural changes weaken magnetic order and alter magnetic moments through combined effects of crystal field perturbations.

Contribution

It provides experimental and theoretical insights into the evolution of magnetic properties with Y content, highlighting the role of structural distortions and crystal field effects in this intermetallic system.

Findings

Antiferromagnetic order weakens with increasing Y content.

Neutron diffraction shows AFM propagation vector and moment orientation.

Structural distortions influence crystal field parameters and magnetic reorientation.

Abstract

We report measurements of the temperature dependence specific heat, magnetic susceptibility in single crystals of the series of intermetallic compounds Tb$_{1-x}$Y$_x$RhIn$_5$ (nominal concentrations $x= 0.15, 0.30, 0.40, 0.50$ and $0.70$). A mean field approximation to simulate the macroscopic properties along the series has been used. Neutron diffraction data in powdered sample of nominal concentration Tb$_{0.6}$Y$_{0.4}$RhIn$_5$ reveal AFM propagation vector $k=[\frac{1}{2}~0~\frac{1}{2}]$ with the magnetic moments oriented close to the tetragonal \textit{c} axis. We discuss the role of combined effects of crystalline electric field (CEF) perturbations and dilution in the magnetic properties evolution with Y content. In particular, we suggest that changes in the Tb-In first neighbors distances, i.e. the TbIn$_3$ cuboctahedra distortion, are responsible for changes in the Tb crystalline potential and the possible reorientation of Tb magnetic moments for $x>$0.4. This reflects non negligible variations of the $B^{m}_{n}$ crystal field parameters and the energy levels splitting with \textit{x}.