Regensburg 2022 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 8: Ultrafast Magnetization Effects 1
MA 8.4: Vortrag
Montag, 5. September 2022, 15:45–16:00, H37
Temperature dependence of spin interaction parameters in two-sublattice ferrimagnets — •Levente Rózsa1, Severin Selzer1, Niklas Windbacher1, Ulrich Nowak1, and Unai Atxitia2 — 1University of Konstanz, Konstanz, Germany — 2Instituto de Ciencia de Materiales de Madrid, Madrid, Spain
Ferrimagnets consist of two antiferromagnetically coupled sublattices with different magnetic moments, thereby possessing a finite magnetization like ferromagnets. The ferrimagnet magnetite has been known since ancient times, yet ferrimagnets continue to attract research interest in various areas of spintronics from magnons to skyrmions. The properties of ferrimagnets may be tuned between those of ferromagnets and antiferromagnets by changing the temperature. Therefore, determining the temperature dependence of model parameters of ferrimagnets is essential for their accurate description.
Here we present an analytical method for describing the temperature dependence of spin interactions in ferrimagnets, based on Callen's Green's function formalism [1]. The temperature dependence of the Heisenberg and Dzyaloshinsky-Moriya interactions, as well as of the anisotropy terms are derived and compared to known expressions in ferromagnets [2,3]. The role of spin correlations is highlighted in reduced dimensions. The results are compared to numerical simulations of the magnon frequencies and of reversal times of nanoparticles.
[1] H. B. Callen, Phys. Rev. 130, 890 (1963).
[2] L. Rózsa et al., Phys. Rev. B 96, 094436 (2017).
[3] R. F. L. Evans et al., Phys. Rev. B 102, 020412(R) (2020).