SPICE Workshop on Spin textures: Magnetism meets Plasmonics, July 23rd - 25th 2024
Bernd Rellinghaus
In contrast to classical ex-situ spectro-microscopic techniques, in-situ characterizations and the combined application of complementary methods on identical samples not only provide for a more comprehensive insight into the structures and phenomena of interest, but also allow to study their kinetic development under the impact of external stimuli such as magnetic or electric fields [1-3].
The talk will present a short review of our recent endeavors along this line with a focus on our latest findings on the helimagnetic Heusler compound Mn1.4PtSn. Lorentz transmission electron microscopy (LTEM) was used to study the evolution of magnetic phases as a function of (strength and direction of) external magnetic fields. The combination of (i) real space textures as derived from LTEM with (ii) magnetic scattering patterns obtained from complementary small angle resonant X-ray scattering (REXS) as well as (iii) micromagnetic simulations and theoretical calculations allowed us to substantially deepen our understanding of the nature of the magnetic phases in Mn1.4PtSn. We could thus show that due to the material’s uniaxial magnetic anisotropy, a stripe domain-like phase derived from a chiral soliton lattice rather than the previously assumed helical phase forms the ground state of the system. The studies also reveal the occurrence a previously overlooked fan state and provide a detailed understanding as to why and how antiskyrmions are formed along a kinetic pathway defined by a special sequence of to be applied external magnetic fields.
Furthermore, by measuring the anomalous Hall effect in-situ in the transmission electron microscope simultaneously with imaging the emerging magnetic textures using LTEM, we could show that the field-induced formation of antiskyrmions does not give rise to any additional contribution to the Hall effect thereby indicating the lack of any topological Hall effect in the system.
[2] D. Pohl, Y. Lee, D. Kriegner, S. Beckert, S. Schneider, B. Rellinghaus, and A. Thomas, „Probing magnetic properties at the nanoscale: In-situ Hall measurements in a TEM“, Sci. Rep. 13 (2023) 14871. DOI: 10.1038/s41598-023-41985-7
[3] M. Winter, M.C. Rahn, A.S. Sukhanov, D. Wolf, S. Schneider, A. Tahn, D. Pohl, A. Mistonov, B. Achinuq, P. Vir, T. Helm, J.R. Bollard, V. Ukleev, M. Valvidares, H. Popescu, A. Pignedoli,11 M. Azhar, K. Everschor-Sitte, A. Thomas, J. Geck, G. van der Laan, T. Hesjedal, C. Felser, and B. Rellinghaus, „Chiral Soliton Lattice beyond chiral monoaxial helimagnets“, submitted.