Out of equilibrium electronic transport properties of a misfit cobaltite thin film

TL;DR

This study investigates the low-temperature electronic transport in a misfit cobaltite thin film, revealing glassy electronic states, magnetic effects, and non-Gaussian fluctuations, advancing understanding of complex correlated electron systems.

Contribution

It provides the first detailed transport analysis of a 2D misfit cobaltite thin film, highlighting glassy electronic behavior and magnetic effects at low temperatures.

Findings

Observation of Coulomb gap in magnetoresistance

Detection of non-Gaussian telegraphic fluctuations at low T

Identification of magnetic memory effects without aging

Abstract

We report on transport measurements in a thin film of the 2D misfit Cobaltite $Ca_{3}Co_{4}O_{9}$. Dc magnetoresistance measurements obey the modified variable range hopping law expected for a soft Coulomb gap. When the sample is cooled down, we observe large telegraphic-like fluctuations. At low temperature, these slow fluctuations have non Gaussian statistics, and are stable under a large magnetic field. These results suggest that the low temperature state is a glassy electronic state. Resistance relaxation and memory effects of pure magnetic origin are also observed, but without aging phenomena. This indicates that these magnetic effects are not glassy-like and are not directly coupled to the electronic part.