Complex domain-wall dynamics in compressively strained Ga1-xMnxAs epilayers

The domain-wall-induced reversal dynamics in compressively strained Ga1-xMnxAs was studied employing the magneto-optical Kerr effect and Kerr microscopy. Due to the influence of a uniaxial part in the in-plane magnetic anisotropy 90 degrees +/-delta domain walls with considerably different dynamic behavior are observed. While the 90 degrees+delta reversal is identified to be propagation dominated with a small number of domains, the case of 90 degrees-delta reversal involves a larger number of nucleation centers. The domain-wall nucleation/propagation energies epsilon for both transitions are estimated using model calculations from which we conclude that single domain devices can be achievable using the 90 degrees+delta mode.