Synchrotron x-ray scattering of UN and U2N3 epitaxial films

Abstract

We examine the magnetic ordering of UN and of a closely related nitride, U2N3, by preparing thin epitaxial films and using synchrotron x-ray techniques. The magnetic configuration and subsequent coupling to the lattice are key features of the electronic structure. The well-known antiferromagnetic (AF) ordering of UN is confirmed, but the expected accompanying distortion at Tn is not observed. Instead, we propose that the strong magneto-elastic interaction at low temperature involves changes in the strain of the material. These strains vary as a function of the sample form. As a consequence, the accepted AF configuration of UN may be incorrect. In the case of cubic a-U2N3, no single crystals have been previously prepared, and we have determined the AF ordering wave-vector. The AF Tn is close to that previously reported. In addition, resonant diffraction methods have identified an aspherical quadrupolar charge contribution in U2N3 involving the 5f electrons; the first time this has been observed in an actinide compound.

References in corpus (4)

• Electronic Correlation and Transport Properties of Nuclear Fuel Materials
• The magnetic structure of bixbyite a-Mn2O3: a combined density functional theory DFT+U and neutron diffraction study
• Itinerant Nature of U 5f States in Uranium Mononitride UN Revealed by Angle Resolved Photoelectron Spectroscopy
• Quantum oscillations of nitrogen atoms in uranium nitride

Cited by in corpus (4)

• Synchrotron Radiation Techniques and their Application to Actinide Materials
• Advances in actinide thin films: synthesis, properties, and future directions
• Fermi-surface reconstruction at the metamagnetic high-field transition in uranium mononitride
• Anisotropic Resonant Scattering from uranium systems at the U M4 edge