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HL: Fachverband Halbleiterphysik
HL 4: Spintronics: Nanostructures and Optics
HL 4.3: Talk
Monday, March 7, 2016, 10:00–10:15, H13
Fe doped InAs: what is the exchange interaction? — •Ye Yuan1, René Hübner1, Kay Potzger1, Fang Liu1, Maciej Sawicki2, Tomasz Dietl2, Manfred Helm1, and Shengqiang Zhou1 — 1Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany — 2Institute of Physics, Polish Academy of Sciences, Warsaw, Poland
Fe doped InAs layers have been prepared by ion implantation and pulsed laser annealing. Fe ions exist in the +3 valence state when located in Indium sites, which indicates that Fe atoms do not introduce free carriers in the InAs layer and only act as the local spins. However, (In, Fe)As or (In, Fe)As n-type doped with Se exhibits properties typical to a blocked superparamagnet, as proven by both static and dynamic magnetic measurements. This is most probably due to the formation of Fe-rich nanoregions in the InAs matrix, similarly to the case of Cr-doped ZnTe [1]. However, the p-type doping with Zn increases both the saturation magnetization and the Curie temperature. A systematic comparison between (In, Fe)As, (In, Fe)As: Zn and (In, Fe)As: Se leads to the re-affirmation of the pd-exchange as the key gradient in dilute ferromagnetic semiconductors [2].
[1]. K. Kanazawa et al., Nanoscale, 6, 14667-14673 (2014) [2]. T. Dietl et al., Science, 287, 1019-1022 (2000)