Dresden 2014 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 55: Poster II
MA 55.113: Poster
Freitag, 4. April 2014, 10:30–13:30, P2
Spin dynamics and magnetic interactions of Mn dopants in the topological insulator Bi2Te3 — •S. Zimmermann1,2, V. Kataev1, Huiwen Ji3, R.J. Cava3, and B. Büchner1,2 — 1IFW Dresden, Germany — 2TU Dresden, Germany — 3Department of Chemistry, Princeton University, USA
Doping of a topological insulator (TI) with magnetic elements can break the time reversal symmetry and thus open a gap in the protected spin polarized conducting surface states, driving the system into a quantum spin Hall regime [1]. Understanding of the interactions between localized magnetic moments of dopants via delocalized electrons that give rise to ferromagnetism in TIs is therefore of significant interest. Electron Spin Resonance (ESR) spectroscopy is a sensitive local technique that can probe interactions of localized spins with conduction electrons as well as spin-spin interactions in semiconductors and metals [2]. In this contribution we report an ESR study of the Mn spin dynamics and magnetic interactions in high-quality single crystals of the Mn doped 3-dimensional TI Bi2Te3 [3]. We have observed a well-defined ESR signal from Mn spins and have studied the temperature dependences of the ESR parameters for a set of Bi2Te3 crystals with different Mn doping levels. The experimental ESR data will be presented in detail. In addition the results from magnetization and transport measurements are taken into account to discuss the Mn spin relaxation via conducting states and the establishment of ferromagnetic order. [1] R. Yu et al., Science 369, 61 (2010); [2] S. E. Barnes, Adv. Phys. 30, 801 (1981); [3] Y.S. Hor et al., PRB 81, 195203 (2010)