Epitaxy, stoichiometry, and magnetic properties of Gd-doped EuO films on YSZ (001)

TL;DR

This study demonstrates the successful growth of high-quality Gd-doped EuO films with controlled stoichiometry and magnetic properties, showing increased Curie temperature with doping, using advanced epitaxial techniques.

Contribution

It introduces a method for producing Gd-doped EuO films with stabilized layer-by-layer growth and precise doping control, enhancing magnetic properties.

Findings

Curie temperature increases with Gd doping up to 125 K

Gd stabilizes layer-by-layer epitaxial growth

Absence of Eu3+ contaminants confirmed

Abstract

We have succeeded in preparing high-quality Gd-doped single-crystalline EuO films. Using Eu-distillation-assisted molecular beam epitaxy and a systematic variation in the Gd and oxygen deposition rates, we have been able to observe sustained layer-by-layer epitaxial growth on yttria-stabilized cubic zirconia (001). The presence of Gd helps to stabilize the layer-by-layer growth mode. We used soft x-ray absorption spectroscopy at the Eu and Gd M4,5 edges to confirm the absence of Eu3+ contaminants and to determine the actual Gd concentration. The distillation process ensures the absence of oxygen vacancies in the films. From magnetization measurements we found the Curie temperature to increase smoothly as a function of doping from 70 K up to a maximum of 125 K. A threshold behavior was not observed for concentrations as low as 0.2%.