Case for Bragg diffraction by a noncollinear PT -symmetric antiferromagnet S. W. Lovesey, G. van der Laan

Antiferromagnetic compounds chromium sesquioxide (Cr2O3) and dioxomolybdenum selenite present linear magnetoelectric effects. Anti-inversion symmetry in the corresponding magnetic crystal classes dictate the makeup of magnetic Bragg diffraction patterns. Copper axial and polar magnetic multipoles contribute to resonant x-ray and magnetic neutron amplitudes in a symmetry informed analysis of monoclinic Cu2(MoO4)(SeO3) presented with a view to steering future diffraction experiments. The compound might be viewed as a low-dimensional quantum magnet on account of its crystal structure and the quantum nature of the Cu spin (S = 1/2).