Non-adiabatic small polaron hopping in the n=3 Ruddlesden-Popper compound Ca4Mn3O10

TL;DR

This paper investigates the magnetotransport properties of Ca4Mn3O10, revealing non-adiabatic small polaron hopping behavior influenced by magnetic order and external fields, with a crossover to variable-range hopping conduction at the Néel temperature.

Contribution

It provides a detailed interpretation of magnetotransport in Ca4Mn3O10 based on small polaron hopping and identifies a crossover to VRH conduction near the magnetic transition.

Findings

Magnetotransport explained by non-adiabatic small polaron hopping.

External magnetic field reduces hopping barrier, increasing conductivity.

Crossover to variable-range hopping occurs at the antiferromagnetic transition.

Abstract

Magnetotransport properties of the compound Ca4Mn3O10 are interpreted in terms of activated hopping of small magnetic polarons in the non-adiabatic regime. Polarons are most likely formed around Mn3+ sites created by oxygen substoichiometry. The application of an external field reduces the size of the magnetic contribution to the hopping barrier and thus produces an increase in the conductivity .We argue that the change in the effective activation energy around TN is due to the crossover to VRH conduction as antiferromagnetic order sets in.