Epitaxial influence on the ferromagnetic semiconducotor EuO

TL;DR

This study uses first principles calculations to explore how epitaxial strain affects the electronic structure and magnetic properties of EuO, revealing that in-plane compression can significantly increase its Curie temperature and alter exchange mechanisms.

Contribution

It provides new insights into how epitaxial strain influences EuO's magnetic and electronic properties, highlighting the role of lattice compression and epitaxial effects.

Findings

Decreasing lattice parameters increases Curie temperature.

Epitaxial strain influences magnetic exchange mechanisms.

Semiconducting gap closes at 6% in-plane compression.

Abstract

From first principles calculations we investigate the electronic structure and the magnetic properties of EuO under hydrostatic and epitaxial forces. There is a complex interdependence of the O 2p and Eu 4f and 5d bands on the magnetism in EuO, and decreasing lattice parameters is an ideal method to increase the Curie temperature, T_c. Compared to hydrostatic pressure, the out-of-plane compensation that is available to epitaxial films influences this increase in T_c, although it is minimized by the small value of poisson's ratio for EuO. We find the semiconducting gap closes at a 6% in-plane lattice compression for epitaxy, at which point a significant conceptual change must occur in the active exchange mechanisms.