Magnetization reversal in multilayer film-device structures

While magnetization reversal in a large film sheet under uniform-field excitation is determined by the macroscopic anisotropy property and microscopic magnetization ripple structure, the magnetization reversal in miniaturized multilayer devices, in addition, depends strongly on the geometry of the device structures. Earlier papers reported the study of coupled-film strips using a nanosecond microscopic Kerr apparatus and simultaneous inductive and magneto-optic-measurement techniques. The present paper describes the reversal behavior in two coupled-film structures, in which the easy axis of each Permalloy layer may be aligned parallel to the strip length (closed hard axis or CHA) or perpendicular to the strip length (closed easy axis or CEA). The Permalloy layers may also be mismatched in thickness. When a Permalloy backing is added to the external drive line as a keeper, the reversal phenomena in both the storage layers and the keeper have been observed. © 1968 The American Institute of Physics.