An ab-initio investigation of magnetism in two-dimensional uranium systems

TL;DR

This study uses density-functional theory to investigate the magnetic properties of two-dimensional uranium systems, revealing how magnetic moments behave at interfaces and surfaces, with implications for understanding uranium-based magnetic materials.

Contribution

It provides the first ab-initio calculations of magnetic moments and XMCD spectra in 2D uranium systems, comparing different exchange-correlation approaches.

Findings

Antiparallel U and Co moments lead to vanishing ferromagnetism in thin Co layers.

U moments decay rapidly away from the surface.

Different exchange-correlation methods yield similar results.

Abstract

The orbital and spin magnetic moments, and the X-ray-magnetic circular-dichroism (XMCD) spectra at the $M_{4,5}$ edges of the U atoms in a UAs/Co multilayer and in an $\alpha$-U film are calculated within the framework of the density-functional theory in combination with the local-spin-density approximation (LSDA), the generalized-gradient approximation (GGA) and the LDA+$U$ method. The antiparallel arrangement between the U and Co spin magnetic moments at the interface results in the vanishing of ferromagnetism for the case of very thin Co layers. The U moments decay rapidly with the distance from the film surface. The magnitude of the magnetic-dipole term $<T_z>$, which appears in the spin XMCD sum rule, is small. The different exchange-correlation treatments do not yield qualitatively different results.