Temperature dependent Neel wall dynamics in GaMnAs/GaAs

Extensive Kerr microscopy studies reveal a strongly temperature dependent domain wall dynamics in Hall-bars made from compressively strained GaMnAs. Depending on the temperature magnetic charging of domain walls is observed and nucleation rates depend on the Hall-geometry with respect to the crystal axes. Above a critical temperature where a biaxial-to-uniaxial anisotropy transition occurs a drastic increase of nucleation events is observed. Below this temperature, the nucleation of domains tends to be rather insensitive to temperature. This first spatially resolved study of domain wall dynamics in patterned GaMnAs at variable temperatures has important implications for potential single domain magneto-logic devices made from ferromagnetic semiconductors.