Kevin Jenni
(University of Cologne)
SrRuO is one of the very few perovskite metallic ferromagnets; it exhibits anomalous transport, an invar effect, non-Fermi liquid behavior, a magnetic shape-memory effect and it is an important substrate for various oxide heterostructures. Strong spin-orbit coupling (SOC) is visible in the invar effect and the large magnetic anisotropy. Recently, we could grow large single crystals of SrRuO using the floating-zone technique [1,2]. We report the first inelastic neutron scattering study of the spin dynamics on single crystals. Our results yield the expected quadratic spin wave dispersion of a ferromagnet. However the magnon gap and stiffness considerably deviate from an earlier inelastic neutron scattering study on powders [3]. In addition we find a non-monotonous temperature dependence of the anisotropy gap and a softening of the magnon stiffness upon cooling. These phenomena can be explained by Weyl physics. We discuss how Weyl modes caused by SOC in SrRuO couple electronic and spin degrees of freedom and how this interplay leads to the characteristic behavior in the spin dynamics [4].
[1] S. Kunkemöller et al., Chrys. Res Tec. 51, 299 (2016)
[2] S. Kunkemöller et al., PRB 96, 220406(R) (2017)
[3] S. Itoh et al., Nat. Commun. 7, 11788 (2016)
[4] K. Jenni et al., Phys. Rev. Lett. 123, 017202 (2019)
Kevin Jenni
(University of Cologne)
Stefan Kunkemoeller
(Universität zu Köln)
Daniel Brüning
(Universität zu Köln)
Thomas Lorenz
(Universität zu Köln)
Yvan Sidis
(Laboratoire Léon Brillouin)
Astrid Schneidewind
Agung A. Nugroho
(Institut Teknologi Bandung)
Achim Rosch
(Universität zu Köln)
Daniel I. Khomskii
Prof.
Markus Braden
(Universität zu Köln)
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