Structural properties of epitaxial {\alpha}-U thin films on Ti, Zr, W and Nb

TL;DR

This study investigates the epitaxial growth and structural properties of orthorhombic uranium ({eta}-U) thin films on various metal substrates, revealing new epitaxial relationships and detailed structural characteristics using advanced X-ray techniques.

Contribution

It reports new epitaxial matches of {eta}-U on Ti and Zr substrates and provides detailed structural analysis of Nb and W buffered {eta}-U systems, advancing understanding of uranium thin film epitaxy.

Findings

Discovered new epitaxial matches of {eta}-U on Ti and Zr surfaces.

Provided detailed structural characterization of Nb and W buffered {eta}-U layers.

Identified the complexity of uranium epitaxy and its potential for electronic property studies.

Abstract

Thin layers of orthorhombic uranium ({\alpha}-U) have been grown onto buffered sapphire substrates by d.c. magnetron sputtering, resulting in the discovery of new epitaxial matches to Ti(00.1) and Zr(00.1) surfaces. These systems have been characterised by X-ray diffraction and reflectivity and the optimal deposition temperatures have been determined. More advanced structural characterisation of the known Nb(110) and W(110) buffered {\alpha}-U systems has also been carried out, showing that past reports of the domain structures of the U layers are incomplete. The ability of this low symmetry structure to form crystalline matches across a range of crystallographic templates highlights the complexity of U metal epitaxy and points naturally toward studies of the low temperature electronic properties of {\alpha}-U as a function of epitaxial strain.