Dresden 2009 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 24: Magnetic Semiconductors
MA 24.12: Vortrag
Mittwoch, 25. März 2009, 17:45–18:00, HSZ 401
Evidence for a magnetic proximity effect up to room temperature at Fe/(Ga,Mn)As interfaces — Francesco Maccherozzi1, Matthias Sperl2, Giancarlo Panaccione2, Giorgio Rossi1,3, Jan Minar4, Svitlana Polesya4, Hubert Ebert4, Ursula Wurstbauer2, Georg Woltersdorf2, Werner Wegscheider2, and •Christian Back2 — 1Laboratorio Nazionale TASC, INFM-CNR — 2Fakultät für Physik, Universität Regensburg — 3Dipartimento di Fisica, Universita di Modena e Reggio Emilia — 4Department of Chemistry, Ludwig-Maximilians University Munich
The combination of Diluted Ferromagnetic Semiconductors (DMS) and conventional semiconductors promises electronic devices with new functionalities such as non-volatility and the additional spin degree of freedom. Here we demonstrate that the low Curie temperature of DMS can be increased by using ferromagnetic proximity polarization. We show that a thin layer of (Ga,Mn)As can be spin polarized at room temperature by the proximity to an iron overlayer. X-ray magnetic circular dichroism and superconducting quantum interference device magnetometry are used to study magnetic order in the iron film and in (Ga,Mn)As films. We conclude that the induced magnetic order in the (Ga,Mn)As layer extends over more than 2 nm, even at room temperature. Furthermore, we show by experiment as well as by theory that the magnetic moments of the Mn ions are coupled antiparallel to the magnetization direction of the Fe layer. Our findings indicate that the ferromagnetic proximity polarization effect can be used to control the spin state of a thin DMS at room temperature.