Infrared observation of the Hund's mechanism in an electron-doped manganite

TL;DR

This study uses infrared spectroscopy to investigate Hund's mechanism in electron-doped manganite Sr{1-x}Ce{x}MnO{3}, revealing how magnetic order influences electron hopping energies and electronic splittings.

Contribution

It provides direct measurements of electron hopping energies related to Hund's coupling in a manganite, linking magnetic phases to electronic structure changes.

Findings

Observation of a shift from 0.3 eV to 0.9 eV absorption bands with magnetic phase transition

Quantitative determination of Hund's, crystal-field, and Jahn-Teller splittings in Mn ions

Correlation between magnetic order and electron hopping energies in doped manganite

Abstract

In the mid-infrared absorption of Sr{1-x}Ce{x}MnO{3} at low electron doping (x = 0.05), a band at 0.3 eV is fully replaced by another one at 0.9 eV as the system becomes antiferromagnetic (AF) of type $G$. A weaker effect occurs at x = 0.10 for an AF phase of type $C$. One thus directly measures the electron hopping energies for spin parallel and anti-parallel to that of the host ion. The Hund's, crystal-field, and Jahn-Teller splittings for the Mn{3+} ions in a Mn{4+} matrix, can also be derived.