Eijin Moriwaki

180° wall movement in a magnetic thin‐film closure domain structure in a high‐frequency field

The dynamic behavior of a 180° wall was observed in a Co‐based amorphous alloy film using a Kerr microscope. As a function of an anisotropy direction the amplitude of the 180° wall movement was measured with the drive field applied transverse to the 180° wall of the closure domain structure. The anisotropy direction was varied by magnetic heat treatment. It was found that the 180° wall moved independently of the anisotropy direction, that is, the 180° wall movement is related only to the applied high‐frequency field. To clarify the cause of the 180° wall movement, the magnetic energy of the domain structure and the eddy current loss caused by the high‐frequency field were calculated. However, the movement could not be understood completely in terms of energy balance since the magnetostatic energy increases faster than the decrease of the eddy current loss, when the 180° wall moves.