Nonlinear Hall effect as a signature of electronic phase separation in the semimetallic ferromagnet EuB6

TL;DR

This paper investigates the nonlinear Hall effect in EuB6, revealing a phase transition linked to electronic phase separation and percolation phenomena, with a model fitting the experimental data well.

Contribution

It introduces a novel interpretation of the nonlinear Hall effect as a signature of electronic phase separation in EuB6, supported by a two-component empirical model.

Findings

Hall resistivity slope switch at a critical magnetization

Percolation of conducting magnetic regions affects conductivity

Empirical model accurately fits the nonlinear Hall data

Abstract

This work reports a study of the nonlinear Hall Effect (HE) in the semimetallic ferromagnet EuB6. A distinct switch in its Hall resistivity slope is observed in the paramagnetic phase, which occurs at a single critical magnetization over a wide temperature range. The observation is interpreted as the point of percolation for entities of a more conducting and magnetically ordered phase in a less ordered background. With an increasing applied magnetic field, the conducting regions either increase in number or expand beyond the percolation limit, hence increasing the global conductivity and effective carrier density. An empirical two-component model expression provides excellent scaling and a quantitative fit to the HE data and may be applicable to other correlated electron systems.