Optical properties and electronic structure of multiferroic hexagonal orthoferrites RFeO3 (R=Ho, Er, Lu)

TL;DR

This study investigates the optical properties and electronic structure of epitaxial multiferroic hexagonal RFeO3 thin films, revealing absorption features and magnetic ordering effects through optical spectroscopy.

Contribution

It provides new insights into the optical absorption spectra and magnetic ordering phenomena of hexagonal RFeO3 thin films, considering the unique fivefold coordination of Fe(3+).

Findings

Films are transparent below 1.9 eV.

Four broad absorption bands observed above 1.9 eV.

Anomaly at 124 K indicates magnetic ordering.

Abstract

We report on optical studies of the thin films of multiferroic hexagonal (P.G. 6mm) rare-earth orthoferrites RFeO3 (R=Ho, Er, Lu) grown epitaxially on a (111)-surface of ZrO2(Y2O3) substrate. The optical absorption study in the range of 0.6-5.6 eV shows that the films are transparent below 1.9 eV; above this energy four broad intense absorption bands are distinguished. The absorption spectra are analyzed taking into account the unusual fivefold coordination of the Fe(3+) ion. Temperature dependence of the optical absorption at 4.9 eV shows anomaly at 124 K, which we attribute to magnetic ordering of iron sublattices.