Temperature-dependent Néel wall dynamics in GaMnAs/GaAs

Extensive Kerr microscopy studies reveal strongly temperature-dependent domain wall (DW) dynamics in Hall bars made from compressively strained GaMnAs. Depending on the temperature, magnetic charging of the DWs is observed, and the 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 in nucleation events is observed. Below this temperature, the nucleation of domains tends to be rather insensitive to temperature. This spatially resolved study of the DW dynamics in patterned GaMnAs at variable temperature has important implications for potential applications in single DW magneto-logic devices made from ferromagnetic semiconductors.