2003/12/31 by T. Last, S. Hacia, M. Wahle +2
Physics and Astronomy · #cond-mat.other
paper · pdf · doi:10.1063/1.1810197
published as J. Appl. Phys. 96 (11), 6706-6711 (2004). · revised version, major structural changes, figures reorganized,6 pages, 8 figures, revtex
arxiv created 2004/06/18 · arxiv updated 2009/12/01
Ferromagnetic electrodes of a lateral semiconductor-based spin-valve structure are designed to provide a maximum of spin-polarized injection current. A single-domain state in remanence is a prerequisite obtained by nanostructuring Permalloy thin film electrodes. Three regimes of aspect ratios m are identified by room temperature magnetic force microscopy: (i) high-aspect ratios of m ≥ 20 provide the favored remanent single-domain magnetization states, (ii) medium-aspect ratios m ∼ 3 to m ∼ 20 yield highly remanent states with closure domains and (iii) low-aspect ratios of m ≤ 3 lead to multi-domain structures. Lateral kinks, introduced to bridge the gap between micro- and macroscale, disturb the uniform magnetization of electrodes with high- and medium-aspect ratios. However, vertical flanks help to maintain a uniformly magnetized state at the ferromagnet-semiconcuctor contact by domain wall pinning.