Dresden 2006 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 9: Poster I
HL 9.91: Poster
Montag, 27. März 2006, 15:15–17:45, P3
Magnetic Anisotropies in (Ga,Mn)As-Hallbars — •S. Hümpfner, K. Pappert, O. Rival, T. Borzenko, J. Wenisch, C. Gould, G. Schmidt, and L.W. Molenkamp — Physikalisches Institut (EP3), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
The ferromagnetic semiconductor (Ga,Mn)As has become a widely used material in semiconductor spintronics. For device design and the understanding of its transport behaviour it is crucial to understand the rich anisotropy landscape of this material.
We investigate the magnetic anisotropy of structures made from thin LT-(Ga,Mn)As layers grown on a GaAs buffer. The anisotropic magnetoresistance (AMR) enables us to map the magnetic anisotropy landscape through careful transport studies. We show how non-local longitudinal (Rxx)and in-plane Hall (Rxy) resistance measurements on Hall bars complement each other in this analysis. We then discuss the influence that different parameters such as the Hall bar design, its orientation with respect to the (Ga,Mn)As crystal, and annealing have on the measured (Rxx) and (Rxy)patterns and deduce the underlying magnetic anisotropies at 4.2 K. Conclusions on the possible origin of different (Ga,Mn)As anisotropy terms are drawn, which will help to controllably create or avoid certain magnetic configurations in future device designs.