A case for resonant X‐ray Bragg diffraction by a collinear antiferromagnet Li 2 Ni 3 P 4 O 14

Journal article

Magnetic axial and polar (Dirac) nickel multipoles contribute to resonant X‐ray Bragg amplitudes in a symmetry‐informed analysis of monoclinic Li2Ni3P4O14 presented for future diffraction experiments. Magnetic long‐range order below a temperature of ≃ 14.5 K can be viewed as a two‐dimensional trimerized antiferromagnet with Ni ions in two Wyckoff positions in the centrosymmetric (1) magnetic space group P21/c. It permits the coupling to circular polarization in the primary X‐ray beam, unlike the corresponding diffraction by an antiferromagnet characterized by anti‐inversion (1′) and a linear magnetoelectric effect, e.g. historically significant chromium sesquioxide (Cr2O3) and Cu2(MoO4)(SeO3) [Lovesey & van der Laan (2024). Phys. Rev. B110, 174442]. The space group is inferred from neutron Bragg diffraction patterns, without an allowance for permitted Dirac dipoles (anapoles) and quadrupoles [Chikara et al. (2025). Phys. Rev. B112, 014438].

Authors: Lovesey, SW

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: International Union of Crystallography
• Journal: Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials
• Volume: 81
• Issue: 6
• Publication date: 2025-11-14
• Acceptance date: 2025-10-29
• DOI: 10.1107/s2052520625009485
• EISSN: 2052-5206
• ISSN: 2052-5192
• Language: English
• Keywords: anapoles; antiferromagnet; Bragg diffraction; chiral signature; resonant X‐ray scattering