Magnetotransport in Fe3O4 nanoparticle arrays dominated by non-collinear surface spins

TL;DR

This study investigates magnetotransport in Fe3O4 nanoparticle arrays, revealing that non-collinear surface spins dominate magnetoresistance behavior across different charge transport mechanisms and annealing conditions.

Contribution

It demonstrates that magnetoresistance in Fe3O4 nanoparticle arrays is universally governed by non-collinear surface spins, regardless of the underlying charge transport process.

Findings

Magnetoresistance fits a Langevin-like function across conditions

Charge transport shifts from tunneling to hopping with decreasing interparticle spacing

Non-collinear surface spins dominate magnetoresistance behavior

Abstract

Magnetotransport in arrays of monodisperse magnetite nanoparticles has been studied as a function of annealing temperatures. Charge transport mechanisms change from thermally assisted interparticle tunneling to hopping between Fe-sites within the particle as the interparticle spacing is decreased. Despite this difference, magnetoresistance (MR) as a function of field shows a ubiquitous behavior dominated by non-collinear surface spins. All MR as a function of field can be fitted accurately by a Langevin-like function.