Short-range magnetic correlations in the highly-correlated electron compound CeCu$_{4}Ga

TL;DR

This study investigates the magnetic properties of CeCu4Ga, revealing persistent short-range magnetic correlations and heavy-electron behavior at very low temperatures without long-range order, suggesting complex magnetic fluctuations.

Contribution

It provides experimental evidence of short-range magnetic correlations and heavy-electron characteristics in CeCu4Ga, contrasting with typical long-range magnetic order in similar compounds.

Findings

Short-range magnetic correlations persist down to 0.1 K.

No evidence of long-range magnetic order despite specific heat peak.

Inelastic neutron scattering shows a magnetic excitation at 0.24 meV.

Abstract

We present experimental results for the heavy-electron compound CeCu$_{4}$Ga which show that it possesses short-range magnetic correlations down to a temperature of $T = 0.1$ K. Our neutron scattering data show no evidence of long-range magnetic order occurring despite a peak in the specific heat at $T^{*} =1.2$ K. Rather, magnetic diffuse scattering occurs which corresponds to short-range magnetic correlations occurring across two unit cells. The specific heat remains large as $T\sim0$ K resulting in a Sommerfeld coefficient of $\gamma_{0} = 1.44(2)$ J/mol-K$^{2}$, and, below $T^{*}$, the resistivity follows $T^{2}$ behavior and the ac magnetic susceptibility becomes temperature independent. A magnetic peak centered at an energy transfer of $E_{\rm{c}}=0.24(1)$ meV is seen in inelastic neutron scattering data which shifts to higher energies and broadens under a magnetic field. We discuss the coexistence of large specific heat, magnetic fluctuations, and short-range magnetic correlations at low temperatures and compare our results to those for materials possessing spin-liquid behavior.