Disorder, inhomogeneity and spin dynamics in f-electron non-Fermi liquid systems

Abstract

Muon spin rotation and relaxation(μSR) experiments have yielded evidence that structural disorder is an important factor in manyf-electron-based non-Fermi-liquid (NFL) systems. Disorder-driven mechanisms for NFLbehaviour are suggested by the observed broad and strongly temperature-dependentμSR (and NMR) linewidths in several NFL compounds and alloys. Local disorder-driventheories (Kondo disorder, Griffiths–McCoy singularity) are, however, not capable ofdescribing the time-field scaling seen in muon spin relaxation experiments, which suggestcooperative and critical spin fluctuations rather than a distribution of local fluctuationrates. A strong empirical correlation is established between electronic disorder and slowspin fluctuations in NFL materials.