Field-induced anomaly in the anisotropic non-Fermi-liquid normal state of UBe$_{13}$

TL;DR

This study investigates the magnetic and thermodynamic properties of UBe$_{13}$ under various magnetic fields, revealing field-induced anomalies, suppression of non-Fermi-liquid behavior, and evidence of multipolar correlations affecting the electronic state.

Contribution

It provides new insights into the field-induced crossover from non-Fermi-liquid to Fermi-liquid states and uncovers thermodynamic anomalies and nonlinear susceptibilities in UBe$_{13}$.

Findings

Suppression of NFL behavior with increasing magnetic field.

Observation of thermodynamic anomalies at intermediate fields.

Detection of a nontrivial fifth-order nonlinear susceptibility.

Abstract

We report the results of high-resolution dc magnetization and specific-heat measurements at very low temperatures for a single crystal \color{black} of UBe$_{13}$ in magnetic fields applied along the [001] and [111] directions, in both the normal and superconducting states. In the normal state, magnetic susceptibility $\chi(T) = M/H$ exhibits a logarithmic temperature dependence over a wide temperature range (1-20 K). However, with increasing field, this non-Fermi-liquid (NFL) behavior of $\chi(T) $ at low temperatures is suppressed. Moreover, a susceptibility maximum occurs below 4 T, whereas Fermi-liquid coherence is recovered above 8 T. In addition, thermodynamic anomalies ($T_{\rm A}$ and $H_{\rm A}$) occur in both magnetic susceptibility and specific heat at intermediate fields (6--10 T) along the [111] direction. Furthermore, a nontrivial fifth-order nonlinear susceptibility is observed in the normal-state magnetization of UBe$_{13}$. These results suggest a close relationship between the field-induced multipolar correlations of $5f$-electron degrees of freedom and the Fermi-surface reconstruction accompanying the crossover from the NFL state to the Fermi-liquid state in UBe$_{13}$.