Spin-fluctuation statistics in<i>Cu</i>Mn

Abstract

The resistance of small ${\mathrm{Cu}}_{0.91}$${\mathrm{Mn}}_{0.09}$ samples in the spin-glass phase showed random changes upon thermal cycling, quantitatively showing that random spin configurations affect universal conductance fluctuations. Low-frequency resistance noise showed large non-Gaussian effects, which were inconsistent with the simplest droplet models for spin glasses. A typical spin-rearrangement event involved about ${10}^{4}$ spins. Several detailed statistical parameters were measured for comparison with droplet and hierarchical models.