Real-time direct observation of temperature-dependent domain reversal behavior in epitaxial MnAs film on GaAs(001)

We have investigated temperature-dependent domain reversal behavior in the MnAs film epitaxially grown on GaAs(001) using a magneto-optical microscope capable of real-time direct observation of domain evolution. Interestingly enough, the domain reversal in the temperature range of 20 degrees C similar to 35 degrees C shows the domain wall-motion process with the sawtooth type and, then, it changes to the nucleation-dominant process above 37.5 degrees C. This change could be understood by the decrease of the dipolar interaction energy and the disconnection of the ferromagnetic alpha-MnAs stripes, induced by the decrease of the alpha-MnAs volume ratio with increasing temperature. (c) 2006 American Institute of Physics.