Orbital dependent magnetic exchange interaction in CeX$_{\text{c}}$ (X$_{\text{c}}$=S, Se, Te)

TL;DR

This study investigates the magnetic exchange interactions in cubic antiferromagnetic CeX$_c$ compounds, revealing that these interactions depend on crystal-field levels and differ from mean-field estimates, with stronger interactions linked to the $Gamma_8$ excited state.

Contribution

It demonstrates that magnetic exchange interactions in CeX$_c$ compounds are dependent on crystal-field levels, a novel insight from inelastic neutron scattering data.

Findings

Exchange interaction varies with crystal-field levels.

Interaction with $Gamma_8$ state is stronger.

Discrepancy between $J(q)$ and mean-field interactions.

Abstract

Dispersion relations of the crystal-field excitations in cubic antiferromagnets CeTe, CeSe, and CeS have been investigated by inelastic neutron scattering using single crystalline samples. The Fourier transform of the magnetic exchange interaction $J(q)$ obtained from the crystal-field dispersion is largely different from that of the mean-field interaction obtained from the N\'eel temperature and the Weiss temperature. From detailed reexamination of the magnetic susceptibility and these $J(q)$ relations, we conclude that the magnetic exchange interaction is dependent on the crystal-field levels. The interaction associated with the $\Gamma_8$ excited state is stronger than that with the $\Gamma_7$ ground state.