Kondo behavior, ferromagnetic correlations, and crystal fields in the heavy Fermion compounds Ce3X (X=In, Sn)

TL;DR

This study investigates the magnetic and electronic properties of Ce3In and Ce3Sn heavy Fermion compounds, revealing that ferromagnetic correlations significantly influence their low-temperature behavior alongside Kondo effects and crystal field excitations.

Contribution

It provides detailed experimental insights into the crystal field levels, Kondo temperatures, and the role of ferromagnetic correlations in these compounds, highlighting their combined effect on heavy Fermion behavior.

Findings

Crystal field levels are identified at 13.2 and 44.8 meV for Ce3In, and 18.5 and 36.1 meV for Ce3Sn.

Kondo temperatures are 17 K for Ce3In and 40 K for Ce3Sn.

Ferromagnetic correlations contribute 10-15% to the ground state properties in Ce3In.

Abstract

We report measurements of inelastic neutron scattering, magnetic susceptibility, magnetization, and the magnetic field dependence of the specific heat for the heavy Fermion compounds Ce$_3$In and Ce$_3$Sn. The neutron scattering results show that the excited crystal field levels have energies $E_1$ = 13.2 meV, $E_2$ = 44.8 meV for Ce$_3$In and $E_1$ = 18.5 meV, $E_2$ = 36.1 meV for Ce$_3$Sn. The Kondo temperature deduced from the quasielastic linewidth is 17 K for Ce$_3$In and 40 K for Ce$_3$Sn. The low temperature behavior of the specific heat, magnetization, and susceptibility can not be well-described by J=1/2 Kondo physics alone, but require calculations that include contributions from the Kondo effect, broadened crystal fields, and ferromagnetic correlations, all of which are known to be important in these compounds. We find that in Ce$_3$In the ferromagnetic fluctuation makes a 10-15 % contribution to the ground state doublet entropy and magnetization. The large specific heat coefficient $\gamma$ in this heavy fermion system thus arises more from the ferromagnetic correlations than from the Kondo behavior.