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| Hauptseite > Publikationsdatenbank > Crystal structure and absence of magnetic order in single crystalline RuO2 |
| Hauptseite > Publikationsdatenbank > Crystal structure and absence of magnetic order in single crystalline RuO2 |
| Conference Presentation (Invited) | FZJ-2024-06887 |
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2024
Abstract: RuO2 initially attracted interest in the field of catalysts and microelectronics, but the recent reportof antiferromagnetic order occurring above room temperature and its identificationas an altermagnetic state boosted activities on this material [1,2,3].The combination of spin splitting otherwise characteristic for ferromagnetic order with the linearmagnon dispersion of an antiferromagnetic system may open the path to applications in spintronicsand magnonics [4].However, even the occurrence of magnetic order in RuO2 was recently questioned by muon andneutron experiments as well as by DFT calculations [5-7] and it was proposed that magnetic orderonly occurs in the presence of vacancies [5].We, therefore, performed polarized and unpolarized neutron diffraction experiments on RuO2 crystalsthat were characterized by magnetization and electrical conductance measurements as well asby X-ray diffraction [8].Single crystals were grown by chemical vapor transport using two different transport molecules.In addition a powder sample was obtained by annealing a commercial compound.The neutron experiments were performed on D9, D3 and IN12 and the crystal structure was investigatedon a Bruker D8 venture diffractometer. We were not able to confirm the proposed structuraldistortion in our crystals down to 2K. There are no superstructure reflections [3]breaking the symmetry of the rutile-type structure in the X-ray and long-wave length neutron experiments.Such peaks are observed for short neutron wave lengths but can be attributed to multiplediffraction. The amount of ruthenium vacancies is below a few per cent in our crystals. Polarizedneutron experiments do not indicate magnetic Bragg reflections for the proposed propagation vectorof ⃗k=(0,0,0) [3]. Even magnetic order with a five times smallerordered moment than what is claimed [3] would have yielded significant intensities in our experiment.This antiferromagnetic order can be ruled out in our stoichiometric samples [8].[1] L. Smejkal et al., 2022, Phys. Rev. X 12(3), 031042.[2] L. Smejkal et al., 2022, Phys. Rev. X 12(4), 040501.[3] T. Berjilin et al., 2017, Phys. Rev. Lett. 118, 077201.[4] L. Smejkal et al., 2023, Phys. Rev. Lett. 131, 256703.[5] A. Smolyanyuk et al., 2024, Phys. Rev. B. 109, 134424.[6] M. Hiraishi et al., 2024, Phys. Rev. Lett. 132, 166702.[7] P. Keßler et al., 2024, npj Spintronics 2, 50.[8] L. Kiefer et al., 2024, arXiv, 2410.05850.23
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