Universal conductance fluctuations and low temperature 1/f noise in mesoscopic AuFe spin glasses

TL;DR

This paper investigates intrinsic conductance fluctuations in mesoscopic AuFe spin glass wires, revealing 1/f noise and quantum interference effects influenced by spin configurations below the freezing temperature.

Contribution

It demonstrates the observation of time-dependent conductance fluctuations and their dependence on various parameters in mesoscopic spin glasses, linking them to quantum interference effects.

Findings

Conductance fluctuations exhibit a 1/f spectrum below the spin glass freezing temperature.

Fluctuation amplitude depends on temperature, magnetic field, voltage, and Fe concentration.

Quantum interference effects are sensitive to slowly fluctuating spin configurations.

Abstract

We report on intrinsic time-dependent conductance fluctuations observed in mesoscopic AuFe spin glass wires. These dynamical fluctuations have a 1/f-like spectrum and appear below the measured spin glass freezing temperature of our samples. The dependence of the fluctuation amplitude on temperature, magnetic field, voltage and Fe concentration allows a consistent interpretation in terms of quantum interference effects which are sensitive to the slowly fluctuating spin configuration.