Expansion and collapse of domains with reverse magnetization in (Ga,Mn)As epilayers with perpendicular magnetic easy axis
Résumé
The magnetic domain structure in a ferromagnetic (Ga,Mn)As epilayer with perpendicular magnetic easy-axis is investigated using high-resolution Kerr microscopy (KM). We show that, despite strong hysteresis, domain theory for thermodynamical equilibrium can be used to determine the ratio of the domain wall energy and the magnetic energy. Complementary magnetometry and ferromagnetic resonance (FMR) measurements are used to determine the domain wall energy and thickness and the exchange stiffness constant.