The Role of Grain Boundaries in Determining the Transport Properties in Magnetite

TL;DR

This study investigates how grain boundaries influence electron transport in magnetite near the Verwey transition, revealing their significant role in scattering mechanisms and charge carrier behavior.

Contribution

It demonstrates that grain boundaries are crucial in understanding transport properties and charge sign changes in magnetite near the Verwey transition.

Findings

Grain boundaries significantly affect electron scattering.

Charge carrier sign change is linked to grain boundary formation.

Transport properties are sensitive to crystal symmetry changes.

Abstract

We present magnetoresistance and Hall-effect measurements on single crystal magnetite Fe3O4 close to the Verwey transition Tv = 123.8 K. We show that the formation of grain boundaries accompanying the reduction in crystal symmetry plays a significant role in the electron scattering mechanism, and that grain boundaries can account for the apparent change in sign of the charge carriers below Tv.