Cd-doping effects in Ce2MIn8 (M = Rh and Ir) heavy fermion compounds

TL;DR

This study investigates how Cd-doping influences magnetic ordering and electronic properties in Ce2MIn8 (M=Rh, Ir) heavy fermion compounds, revealing enhanced antiferromagnetism and modifications in magnetic structure and anisotropy.

Contribution

It provides new insights into how Cd-doping affects magnetic structures and crystalline electric field parameters in Ce2MIn8 compounds, expanding understanding of doping effects in heavy fermion systems.

Findings

Cd-doping increases the AFM ordering temperature.

Cd-doping induces a commensurate AFM structure with a specific propagation vector.

Doping modifies the magnetic moment orientation and Ce3+ ground state anisotropy.

Abstract

Low temperature magnetic properties of Cd-doped Ce2MIn8 (M = Rh and Ir) single crystals are investigated. Experiments of temperature dependent magnetic susceptibility, heat capacity and electrical resistivity measurements revealed that Cd-doping enhances the antiferromagnetic (AFM) ordering temperature from TN = 2.8 K (x = 0) to TN = 4.8 K (x = 0.21) for Ce2RhIn8-xCdx and induces long range AFM ordering with TN = 3.8 K (x = 0.21) for Ce2IrIn8-xCdx. Additionally, X-ray and neutron magnetic scattering studies showed that Cd-doped samples present below TN a commensurate antiferromagnetic structure with a propagation vector (1/2,1/2,0). The resolved magnetic structures for both compounds indicate that the Cd-doping tends to rotate the direction of the ordered magnetic moments toward the ab-plane. This result suggests that the Cd-doping affects the Ce3+ ground state single ion anisotropy modifying the crystalline electrical field (CEF) parameters at the Ce3+ site. Indications of CEF evolution induced by Cd-doping were also found in the electrical resistivity measurements. Comparisons between our results and the general effects of Cd-doping on the related compounds CeMIn5 (M = Co, Rh and Ir) confirms the claims that the Cd-doping induced electronic tuning is the main effect favoring AFM ordering in these compounds.