Magnetic multipoles in a ruthenateCa3Ru2O7
| Autor: | G. van der Laan, Dmitry D. Khalyavin, S. W. Lovesey |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Diffraction
Physics Condensed matter physics Magnetic structure Neutron diffraction Order (ring theory) 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Magnetization Ferrimagnetism 0103 physical sciences Antiferromagnetism 010306 general physics 0210 nano-technology Energy (signal processing) |
| Zdroj: | Physical Review B. 99 |
| ISSN: | 2469-9969 2469-9950 |
| DOI: | 10.1103/physrevb.99.134444 |
| Popis: | Compulsory Dirac multipoles in the bilayer perovskite $\mathrm{C}{\mathrm{a}}_{3}\mathrm{R}{\mathrm{u}}_{2}{\mathrm{O}}_{7}$ are absent in published analyses of experimental data. In a first step at correcting knowledge of the magnetic structure, we have analyzed existing Bragg diffraction patterns gathered on samples held well below the N\'eel temperature at which $A$-type antiferromagnetic order of axial dipoles spontaneously develops. Patterns were gathered with neutrons, and linearly polarized x rays tuned in energy to a ruthenium atomic resonance. Neutron diffraction data contain solid evidence of Dirac dipoles (anapoles or toroidal moments). No such conclusion is reached with existing x-ray diffraction data, which instead is ambiguous on the question. To address this shortcoming by future experiments, we calculated additional diffraction patterns. Chiral order of Dirac multipoles is allowed by magnetic space-group ${P}_{C}na{2}_{1}$, and it can be exposed in Bragg diffraction using circularly polarized x rays. Likewise, a similar experiment can expose a chiral order of axial dipoles. A magnetic field applied parallel to the $b$ axis creates a ferrimagnetic structure in which bulk magnetization arises from field-induced nonequivalent Ru sites (magnetic space-group $P{m}^{\ensuremath{'}}{c}^{\ensuremath{'}}{2}_{1})$. |
| Databáze: | OpenAIRE |
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