New Evidence for Zero-Temperature Relaxation in a Spin-Polarized Fermi Liquid

TL;DR

This study provides experimental evidence that spin current relaxation in a spin-polarized Fermi liquid persists at zero temperature, challenging the expectation of complete relaxation cessation in such systems.

Contribution

The paper presents the first measurements of spin diffusion coefficients at ultra-low temperatures near the zero-temperature limit in a spin-polarized Fermi liquid.

Findings

Spin diffusion coefficient D_perp deviates from 1/T^2 dependence at low T.

The anisotropy temperature T_a is approximately 4.26 mK.

Spin current relaxation remains finite as T approaches zero.

Abstract

Spin-echo experiments are reported for 3He-4He solutions under extremely high B/T conditions, B=14.75 T and T >= 1.73 mK. The 3He concentration x_3 was adjusted close to the value x_c = 3.8% at which the spin rotation parameter muM_0 vanishes. In this way the transverse and longitudinal spin diffusion coefficients D_perp, D_parallel were measured while keeping |muM_0| < 1. It is found that the temperature dependence of D_perp deviates strongly from 1/T^2, with anisotropy temperature T_a = 4.26 +/- 0.18 mK. This value is close to the theoretical prediction for dilute solutions, and suggests that spin current relaxation remains finite as the temperature tends to zero.