Spin dynamics in a structurally ordered non-Fermi liquid compound: YbRh_2Si_2

TL;DR

This study uses muon spin relaxation to investigate the spin dynamics in the non-Fermi-liquid heavy-fermion compound YbRh_2Si_2, revealing homogeneous fluctuations and a specific scaling law of the dynamic spin susceptibility.

Contribution

It provides the first muSR analysis of spin fluctuations in YbRh_2Si_2, demonstrating homogeneous dynamics and establishing a scaling law for the spin susceptibility.

Findings

Relaxation function is exponential, indicating homogeneous spin fluctuations.

Relaxation rate scales as H^{-1}, suggesting a specific power-law behavior.

Identifies a scaling law for the dynamic spin susceptibility with frequency and temperature.

Abstract

Muon spin relaxation (muSR) experiments have been carried out at low temperatures in the non-Fermi-liquid heavy-fermion compound YbRh_2Si_2. The longitudinal-field muSR relaxation function is exponential, indicative that the dynamic spin fluctuations are homogeneous. The relaxation rate 1/T_1 varies with applied field as H^{-y}, y = 1.0 \pm 0.1, which implies a scaling law of the form \chi''(\omega) \propto \omega^{-y} f(\omega/T), \lim_{x\to0} f(x) = x for the dynamic spin susceptibility.