Determine the precise in-plane Dy-moment orientation

Determine the precise in-plane orientation of the Dy magnetic moments in tetragonal DyCuAs₂, which remains unresolved because magnetic-domain averaging prevents the azimuthal X-ray resonant magnetic scattering response from uniquely distinguishing among in-plane directions.

Background

The study establishes that DyCuAs₂ orders antiferromagnetically with propagation vector k = (0, 0, 0.5) and is described by the Γ₁₀ magnetic representation. This representation fixes the Dy moments to the tetragonal ab plane and determines a ++−− stacking sequence along the c axis.

However, the tetragonal structure permits multiple magnetic domains. For in-plane moments, averaging over these domains removes the azimuthal angular dependence that would otherwise provide information about the moment direction. Consequently, the measurements identify the moment orientation only as lying within the ab plane and do not resolve its precise crystallographic direction.