Berlin 2005 – wissenschaftliches Programm

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MA: Magnetismus

MA 20: Poster:Schichten(1-29),Spintrsp(30-45),Ex-Bias(46-63),Spindyn(64-75),Mikromat.(76-80),Cluster(81-94),Abbv.(95-99),Obflm(100-02),SpElek.(103-09),E-Theo(110-14),Mikromag.(115-16),Spin+PÜ(117-26),Mag.Mat.(127-51),Meth.(152-55),Mol.Mag(156-59),Kondo(160-65

MA 20.133: Poster

Montag, 7. März 2005, 14:00–18:00, Poster TU C

Magnetic properties of the diluted semiconductor Ge_1−xMn_x (Ge_1−xCo_x) — •Erwin Biegger, Lorenz Stäheli, Mikhail Fonin, and Ulrich Rüdiger — FB Physik/LS Rüdiger/Universitätsstraße10/78457 Konstanz

Diluted magnetic semiconductors (DMS) attract extensive attention because of their possible applications to spintronics based on the semiconductor technology [1]. DMS are made by substitution of small amount of magnetic transition metal (TM) such as Cr, Mn, Fe, Co, and Ni into semiconductors. The coupling mechanism in these systems are still unclear. Recently, Mn substitution has yielded ferromagnetism in germanium with T_C at 285 K in bulk single crystals [2]. Magnetic properties have been investigated between 5 and 400 K. The magnetisation showed two distinct transitions at about 150 K and about 285 K which were identified as antiferromagnet-ferromagnet and ferromagnet-paramagnetic transition, respectively.

Ge_1−xMn_x (Ge_1−xCo_x) have been grown in vertical furnaces. Bulk crystals have been cut to anlyse its crystal structure with X-ray diffraction techniques. SQUID measurements have been done to investigate the magnetic properties.

[1] R. Fiederling et al., Nature (London) 402, 787 (1999); Y. Ohno, D. K. Young, B. Beschoten, F. Matsukura, H. Ohno, and D. D. Awschalom, ibid. 402, 790 (1999); T. Dietl, H. Ohno, F. Matsukura, J. Cibert, and D. Ferrand, Science 287, 1019 (2000). [2] S. Cho et al., Phys. Rev. B 66, 033303 (2002).