Universal charge transport of the Mn oxides in the high temperature limit

TL;DR

This study reveals that various Mn oxides exhibit universal resistivity and thermopower at high temperatures, indicating a common localized conduction mechanism independent of their structural differences.

Contribution

It demonstrates the universal high-temperature charge transport properties of Mn oxides and proposes a localized conduction mechanism involving Mn ion exchange.

Findings

Resistivity approaches 7±1 mΩcm at high T

Thermopower approaches -79±3 μV/K at high T

Universal behavior independent of structure and carrier density

Abstract

We have found that various Mn oxides have the universal resistivity and thermopower in the high temperature limit. The resistivities and thermopowers of all the samples go toward constant values of 7$\pm$1 m$\Omega$cm and $-79\pm$3 $\mu$V/K, which are independent of carrier density and crystal structures. We propose that the electric conduction occurs in a highly localized way in the high temperature limit, where the exchange of entropy and charge occurs in the neighboring Mn$^{3+}$ and Mn$^{4+}$ ions.