Synthesis and physical properties of uranium thin-film hydrides UH2 and \b{eta}-UH3

TL;DR

This study reports the synthesis of stable uranium hydride thin films UH2 and eta-UH3 via reactive sputtering, and characterizes their structural, magnetic, and electrical properties, revealing robust ferromagnetism and disorder effects.

Contribution

It introduces a method to produce oxygen-free uranium hydride thin films and provides detailed characterization of their magnetic and electrical properties.

Findings

Both UH2 and eta-UH3 are ferromagnetic with Curie temperatures of 120 K and 170 K.

Ferromagnetism is robust and independent of structural details.

Electrical resistivity indicates disorder in the hydride films.

Abstract

Formation of thin uranium hydrides films, UH2 and \b{eta}-UH3, synthesized by a reactive dc sputtering of uranium metal, was explored using variable deposition conditions. Obtained stable oxygen-free hydride films were studied by a variety of methods, both in situ (photoelectron spectroscopy - XPS), and ex-situ (x-ray diffraction - XRD, transmission electron microscopy - TEM), electrical resistivity, and magnetometry). Both types of hydrides are ferromagnetic, the Curie temperatures of UH2 and \b{eta}-UH3 are approx. 120 and 170 K, respectively. Ferromagnetism in the thin films is robust and does not depend on structure details while electrical resistivity data reflect disorder in both types of hydrides.