Multi-k magnetic structures in USb_{0.9}Te_{0.1} and UAs_{0.8}Se_{0.2} observed via resonant x-ray scattering at the U M4 edge

TL;DR

This study uses resonant x-ray scattering at the U M4 edge to investigate complex multi-k magnetic structures in USb_{0.9}Te_{0.1} and UAs_{0.8}Se_{0.2}, revealing new insights into their magnetic phase transitions.

Contribution

It provides the first direct observation of <kkk> reflections linked to multi-k magnetic configurations in these uranium-based compounds.

Findings

<kkk> reflections confirm 3k magnetic structure in USb_{0.9}Te_{0.1}

Transition between 2k and 3k states in UAs_{0.8}Se_{0.2} is field-sensitive

Resonant x-ray scattering effectively probes complex magnetic orderings

Abstract

Experiments with resonant photons at the U M4 edge have been performed on a sample of USb_{0.9}Te_{0.1}, which has an incommensurate magnetic structure with k = 0.596(2) reciprocal lattice units. The reflections of the form <kkk>, as observed previously in a commensurate k = 1/2 system [N. Bernhoeft et al., Phys. Rev. B 69 174415 (2004)] are observed, removing any doubt that these occur because of multiple scattering or high-order contamination of the incident photon beam. They are clearly connected with the presence of a 3k configuration. Measurements of the <kkk> reflections from the sample UAs_{0.8}Se_{0.2} in a magnetic field show that the transition at T* ~ 50 K is between a low-temperature 2k and high-temperature 3k state and that this transition is sensitive to an applied magnetic field. These experiments stress the need for quantitative theory to explain the intensities of these <kkk> reflections.