Anomalous magnetization vibration in Co-based amorphous strip films at high frequency

Dynamic response behavior of magnetization within the frequency of 1–20 MHz in Co-based amorphous strip films is observed with a scanning Kerr microscope. When an ac current is applied to the conductor under a strip, immovable and movable magnetic regions appear alternately from the 180° walls to the hexagonal domains. The number of these regions increases by one each time the frequency is increased by an integer times the basic frequency. Moreover, when the magnetic anisotropy and strip-width become large, the number of magnetization immovable regions increases. The 180° walls seem to behave like strings. Standing waves occur on them and this affects the magnetization changes in the hexagonal domains.