Ferromagnetism and increased ionicity in epitaxially grown TbMnO3 films

TL;DR

This study demonstrates that epitaxially grown TbMnO3 films exhibit ferromagnetism below 40K and increased ionicity due to strain effects, differing significantly from bulk properties.

Contribution

It reveals how epitaxial strain induces ferromagnetism and enhances ionicity in TbMnO3 films, providing new insights into strain-engineered magnetic properties.

Findings

Films show ferromagnetic interactions below 40K.

X-ray photoemission indicates increased Mn-3s splitting.

Ab initio calculations confirm higher ionicity in films.

Abstract

Thin films of TbMnO3 have been grown on SrTiO3 substrates. The films grow under compressive strain and are only partially clamped to the substrate. This produces remarkable changes in the magnetic properties and, unlike the bulk material, the films display ferromagnetic interactions below the ordering temperature of ~40K. X-ray photoemission measurements in the films show that the Mn-3s splitting is 0.3eV larger than that of the bulk. Ab initio embedded cluster calculations yield Mn-3s splittings that are in agreement with the experiment and reveal that the larger observed values are due to a larger ionicity of the films.