Observation of magnetic domain structure in a ferromagnetic semiconductor (Ga, Mn)As with a scanning Hall probe microscope

We have performed low-temperature scanning Hall probe microscopy on a ferromagnetic semiconductor (Ga0.957Mn0.043)As. The observed magnetic domain structure is a stripe-shaped pattern as has been observed in conventional nonsemiconductor ferromagnetic materials, and the measured magnetic field from the sample surface was small, reflecting the weak magnetization of (Ga, Mn)As. The domain width increased and the measured magnetic field decreased with raising temperature, which are consistent with calculated results, in which the exchange interaction between Mn spins deduced from the Curie temperature is assumed.