Dresden 2006 – scientific programme

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MA: Magnetismus

MA 2: Magnetic Thin Films I

MA 2.7: Talk

Monday, March 27, 2006, 11:45–12:00, HSZ 03

Magnetic anisotropy of Ga_1−xMn_xAs on GaAs (311)A — •Christoph Bihler¹, Hans Huebl¹, Dieter Schlosser¹, Martin S. Brandt¹, Sebastian T. B. Goennenwein², Matthias Reinwald³, Ursula Wurstbauer³, Matthias Döppe³, Dieter Weiss³, and Werner Wegscheider³ — ¹Walter Schottky Institut, Technische Universität München, Am Coulombwall 3, 85748 Garching, Germany — ²Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Walther-Meissner-Str. 8, 85748 Garching, Germany — ³Universität Regensburg, 93040 Regensburg, Germany

One approach to further improve the magnetic properties of Ga_1−xMn_xAs epilayers via optimized dopant incorporation is growth on higher index GaAs substrates. In this contribution we investigate the magnetic anisotropy of Ga_1−xMn_xAs grown by low-temperature molecular beam epitaxy (LT-MBE) on GaAs (311)A substrates by means of ferromagnetic resonance (FMR) spectroscopy. The angular dependence of the resonance fields observed can be explained by two main contributions to the magnetic anisotropy: a cubic magnetic anisotropy field 2K_C1/M=240 mT oriented along the crystallographic ⟨001⟩ axes caused by the symmetry of the GaAs host lattice, and an effective uniaxial magnetic anisotropy field 2K_eff³¹¹/M=90 mT along [311] presumably caused by the homoepitaxial growth of the layer. Even better agreement between simulation and experiment is obtained if additional uniaxial anisotropies along [100] and [233] are taken into account.