Influence of the initially ordered structure on transition of structural pattern

The influence of the initially ordered state to the structural evolution on the magnetic fluid film under perpendicular magnetic fields was investigated. The magnetic field was increased from zero to a certain strength H_i at a given sweep rate dH/dt and maintained at H_i for a period of time, after which the magnetic field was further raised at dH/dt. The H _i was adequately set so that a granular ordered structure of magnetic columns formed in the magnetic fluid film. This granular ordered structure served as an initial state for the following structural evolution when the magnetic field was increased from H_i. When the magnetic field was raised up to H_s, the structure evolved to the transition state, at which each column split into two columns. To obtain the initial structures of various orderness, the duration time t_d at H _i was varied from 1 to 180s. It was found that the degree of orderness of the initial structure under H_i increases with t _d, and a higher H_s was also observed. This result can be interpreted by taking the interactions between a column and its neighbors into account.