Chirality and magnetic quadrupole order in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>Pb</mml:mi><mml:mrow><mml:mo>(</mml:mo><mml:mi>TiO</mml:mi><mml:mo>)</mml:mo></mml:mrow><mml:msub><mml:mi>Cu</mml:mi><mml:mn>4</mml:mn></mml:msub><mml:msub><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:msub><mml:mi mathvariant="normal">PO</mml:mi><mml:mn>4</mml:mn></mml:msub></mml:mrow><mml:mo>)</mml:mo></mml:mrow><mml:mn>4</mml:mn></mml:msub></mml:mrow></mml:math>probed by interference scatter

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Resonant x-ray diffraction (RXD) measurements at the Tb L 3 and the M 5 edges were carried out on a single crystal of a rare-earth tetraboride, TbB 4 , which exhibits antiferromagnetic (AFM) order breaking both space-inversion and time-reversal symmetries. Considering its crystallographic and magnetic symmetries, both the anisotropic tensor of susceptibility (ATS) scattering and the magnetic scattering contribute to space-groupforbidden odd00 reflections under the resonant conditions in the AFM phase. We found that the RXD intensity of odd00 reflections depends on the helicity of the circularly polarized incident x rays, which is reasonably explained in terms of the interference effect between the ATS and the magnetic scatterings. Furthermore, the circular dichroic RXD showed a sample-position dependence, which reflects spatial distributions of AFM domains in TbB 4 . Our study reveals that RXD using circularly polarized x rays is a powerful technique to probe not only the magnitude but also the sign of AFM order parameters and to spatially resolve AFM domains in materials breaking both space-inversion and time-reversal symmetries.

“…Following the derivation given in Refs. [21,[27][28][29], we obtain the magnetic scattering matrix G,…”

Section: B Formulation Of the Magnetic Scattering Factormentioning

confidence: 99%

Resonant x-ray diffraction study using circularly polarized x rays on antiferromagneticTbB4

Misawa,

Arakawa,

Yoshioka

et al. 2023

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“…These sensitive techniques can reveal non-trivial spin textures or nano-ordered phases that are difficult to probe with other methods. Some examples include multipolar order parameters (1)(2)(3)(4)(5), charge ordering in high-temperature superconductors (6), and ordering in strongly correlated electron systems (7,8) and other quantum materials (9,10).…”

Section: Introductionmentioning

confidence: 99%

Antiferromagnetic real-space configuration probed by dichroism in scattered x-ray beams with orbital angular momentum

McCarter

U.²,

Singh³

et al. 2023

X-ray beams with orbital angular momentum (OAM) are an up-and-coming tool for x-ray characterization techniques. Beams with OAM have an azimuthally varying phase that leads to a gradient of the light field. New material properties can be probed by utilizing the unique phase structure of an OAM beam. Here, we demonstrate a novel type of phase dichroism in resonant diffraction from an artificial antiferromagnet with a topological defect. The scattered OAM beam has circular dichroism whose sign is coupled to the phase of the beam, which reveals the real-space configuration of the antiferromagnetic ground state. Thermal cycling of the artificial antiferromagnet can change the ground state, as indicated by the changing phase dichroism. These results exemplify the potential of OAM beams to probe matter in a way that is inaccessible using typical x-ray techniques.

Magnetic properties of Sohncke-type Pb(TiO) Cu4(PO4)4 exposed by resonant x-ray

Lovesey

2024

The enantiomorphous (chiral) crystal class of Sohncke-type Pb(TiO)Cu4(PO4)4 permits the rotation of the plane of polarization of light (optical activity). Copper ions participate in noncollinear antiferromagnetic order below a temperature ≈ 7 K, with magnetoelectric and piezomagnetic effects permitted. Crystal and magnetic symmetries of Pb(TiO)Cu4(PO4)4 are fully incorporated in calculated resonant x-ray Bragg diffraction patterns that are successfully compared with existing limited experimental data [Misawa , ]. Specifically, there is additional intensity of a Bragg spot (a chiral signature) from circular polarization (helicity) in the primary beam of x rays. The chiral signature is shown to arise from Cu axial magnetic dipoles, with the prospect of future experiments revealing interference between magnetic dipoles and (Templeton-Templeton) chargelike quadrupoles. An expression for the additional intensity used by Misawa does not respect magnetic symmetry, and our symmetry-informed answer overturns their principal conclusions about chirality and magnetic order. Dirac quadrupoles and octupoles are potentially strong sources of diffraction when the reflection vector is parallel to the unique direction in the tetragonal lattice. Notably, a Dirac quadrupole is a parity- and time-odd atomic multipole unlike a multisite spin entity previously mentioned in the context of Pb(TiO)Cu4(PO4)4 [Kimura , ]. Published by the American Physical Society 2024