Magnetic stripe - Bubble domain transition in a 2-dimensional magnetic system

The transition between the stripe domains and the bubble domains in a 2-dimensional magnetic system was studied by using a Monte-Carlo simulation and a model calculation. As the perpendicular external field increases, the stripe domain phase changes its domain structure via two distinctive processes. Firstly, under small external field, a magnetization process occurs with widening of the major domains and shrinking of the minor domains, which results in an asymmetric stripe domain phase. Secondly, as the external field increases further and the width of the minor domain reaches its critical thickness, the minor domain breaks into small domains whose shapes are round. Also, the following magnetization process is completed as the number of the bubble domains decreases. We adopted a Monte-Carlo simulation to reveal the condition of the stripe - bubble domain transition and compared the results with those obtained by using a model numerical calculation.