URu2Si2: recent findings by resonant X-ray diffraction

Vol 1 2021 - 142126
Oral
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Abstract

The hidden order (HO) of URu2Si2 has remained a mystery since its discovery in 1985 [1], despite continuous research effort [2]. A small moment (~0.03 μB/atom) antiferromagnetic (AFM) phase accompanies the hidden order phase [3]. While it is far too small to explain the large effect seen in macroscopic measurements, its role in the phase transition is not clear. Whether it is intrinsic (e.g. a secondary order parameter) or extrinsic (e.g. impurities) remains controversial.
We studied the AFM phase by X-ray resonant magnetic scattering at the Uranium M4 edge. We observed a large macroscopic inhomogeneity of the AFM phase, while the cristalline and chemical homogeneities of the samples were found excellent. In addition, we also discovered several structural anomalies which suggest the presence of a secondary structural phase in the sample.
The puzzling results are reported to the community to seek advice.

Institutions
  • 1 SIMaP / Univ Grenoble Alpes / CNRS
  • 2 Physics / University of Bristol / H. H. Wills Physics Laboratory
  • 3 XMaS CRG beamline / ESRF
  • 4 Diamond Light Source
  • 5 Institute for Materials Research, Tohoku University, Oarai, Ibaraki, 311-1313, Japan
  • 6 Moscow State University
  • 7 Shubnikov Institute of Crystallography
  • 8 Institut Néel / CNRS
Track
  • Strong correlations in actinides
Keywords
URu2Si2
Resonant X-ray Magnetic Diffraction
Phase coexistence