Regensburg 2022 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 20: Topology: Poster Session
TT 20.2: Poster
Wednesday, September 7, 2022, 15:00–18:00, P1
Static and dynamic magnetism of (MnBi2Te4)(Bi2Te3)n (n = 0, 1) probed by electron spin resonance technique. — •Alexey Alfonsov1, Kavita Mehlawat1,2, Jorge I. Facio1, Ali G. Moghaddam1,3, Rajyavardhan Ray1, Alexander Zeugner4,5, Manuel Richter1,5, Anna Isaeva1,6, Jeroen van den Brink1,2,5, Bernd Büchner1,2,5, and Vladislav Kataev1 — 1Leibniz IFW Dresden, 01069 Dresden, Germany — 2Würzburg-Dresden Cluster of Excellence ct.qmat — 3IASBS, Zanjan 45137-66731, Iran — 4H.C. Starck Tungsten GmbH, 38642 Goslar, Germany — 5TU Dresden, 01062 Dresden, Germany — 6University of Amsterdam, 1098 XH Amsterdam, The Netherlands
(MnBi2Te4)(Bi2Te3)n (n = 0, 1) are van der Waals materials which exhibit a coexistence of topologically nontrivial surface states with intrinsic magnetism. In this work we address static and dynamic magnetic properties of the title materials in the ordered and disordered states using multifrequency and high field electron spin resonance technique. We show that the spin dynamics of the magnetic building blocks of these compounds, the Mn-based septuple layers (SLs), is inherently ferromagnetic (FM) featuring persisting short-range FM correlations far above the magnetic ordering temperature as soon as the SLs get decoupled either by introducing a nonmagnetic quintuple interlayer, as in MnBi4Te7, or by applying a moderate magnetic field, as in MnBi2Te4. Additionally, MnBi2Te4 exhibits a strongly anisotropic Mn spin relaxation in the paramagnetic state, which we explain by the sensitivity of the local electronic structure to the Mn spin orientation.