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

Abstract

Muon spin rotation and relaxation ($\\mu$SR) experiments have yielded evidence\nthat structural disorder is an important factor in many f-electron-based\nnon-Fermi-liquid (NFL) systems. Disorder-driven mechanisms for NFL behaviour\nare suggested by the observed broad and strongly temperature-dependent $\\mu$SR\n(and NMR) linewidths in several NFL compounds and alloys. Local disorder-driven\ntheories (Kondo disorder, Griffiths-McCoy singularity) are, however, not\ncapable of describing the time-field scaling seen in muon spin relaxation\nexperiments, which suggest cooperative and critical spin fluctuations rather\nthan a distribution of local fluctuation rates. A strong empirical correlation\nis established between electronic disorder and slow spin fluctuations in NFL\nmaterials\n