Griffiths phases in structurally disordered CeRhSn: Experimental evidence and theoretical modeling

TL;DR

This paper investigates Griffiths phases in structurally disordered CeRhSn, combining experimental evidence of non-Fermi-liquid behavior with theoretical modeling to understand the effects of disorder on quantum states.

Contribution

It provides empirical documentation and numerical analysis supporting Griffiths phase scenarios in CeRhSn, including a proposed magnetic phase diagram for disordered quantum materials.

Findings

Identification of classical Griffiths phase below 220 K

Observation of quantum Griffiths phase below 6 K

Magnetic susceptibility depends on inhomogeneous magnetic particle size

Abstract

Our report paves the way for insight into a structural disorder and its impact on the physical properties of strongly correlated electron systems (SCESs). In a critical regime, each perturbation, e.g., disorder due to structural defects or doping, can have a significant effect on the nature of the quantum macrostate of these materials. For a select group of SCESs, we have empirically documented the Griffiths singularity, as exemplified by CeRhSn, which exhibits non-Fermi-liquid characteristics in susceptibility and specific heat. Our numerical analysis has supported the Griffiths phase scenario for CeRhSn and has revealed that its dc magnetic susceptibility is strongly dependent on the size of inhomogeneous magnetic particles that form in these materials. In the presence of strong disorder, we have proposed a magnetic phase diagram for CeRhSn. The classical Griffiths phase has been identified in the temperature range below the onset temperature of $T_G$ ~ 220 K, while the quantum Griffiths phase with non-Fermi liquid behavior emerges below the quantum critical temperature of $T_Q$ ~ 6 K. The phase diagram developed in this study bears notable similarities to the scenario previously proposed by Vojta for magnetic quantum phase transitions in disordered metals.