TRR404 Guest Talk "Anisotropic Magneto-Transport and Magneto-Thermopower Response of Crystalline Magnetic Films"

Bio: Sebastian T. B. Goennenwein graduated from TechnischeUniversität München (Germany) with a PhD in physics in 2003. Following a postdoc at TU Delft (The Netherlands), he worked as a research group leader and deputy director at Walther-Meissner-Institut, Bavarian Academy of Sciences, Germany. In 2016, Sebastian Goennenwein was appointed full professor at the Faculty of Physics, TechnischeUniversität Dresden. In 2020, he followed a call to a full professor position at the Physics Department of the University of Konstanz. His research addresses spin currents, spin dynamics, spin caloritronics, spin fluctuations as well as topology-related phenomena in multi-functional magnetic heterostructures and devices.

Abstract: The magneto-transport response of magnetically ordered materials –such as the anisotropic magneto-resistance (AMR), or the anomalous Hall effect (AHE) –has been extensively studied in the last decades. While the magneto-transport response of amorphous or polycrystalline samples often can be described by comparatively simple expressions, the implications of crystal symmetry lead to a much richer and more complex response in single-crystalline specimens [1]. In particular, higher-order terms with a seemingly “unconventional” dependence on the magnetization can be allowed by symmetry, and indeed also be detected in experiment [2]. In the presentation, I will first review the implications imposed onto the magneto-transport response by crystal symmetry, and then discuss typical experimental results, focusing on crystalline (Ga,Mn)As films as a prototypical and well-studied example [3,4]. In the last part of the talk, I will then touch upon the impact of crystalline symmetry onto the magneto-thermopower response [5].
[1] R. R. Birss, Symmetry and Magnetism(North-Holland, Amsterdam, 1966)
[2] P. K. Muduli et al., Phys. Rev. B 72, 104430 (2005)
[3] W. Limmer et al., Phys. Rev. B 74, 205202 (2006)
[4] W. Limmer et al., Phys. Rev. B 77, 205210 (2008)
[5] P. Ritzinger et al., Phys. Rev. B 104, 094406 (2021)