Two‐Peak Output Waveforms in Uniform Rotation Switching of Thin Films

Abstract

A theoretical model for high‐drive switching of a thin‐film, finite length, ferrite, cylindrical shell or toroid is developed from Gilbert's equation. The equation of uniform magnetization reversal includes terms which result from an arbitrary applied field and terms due to the axial demagnetizing field. Machine solution of the equation shows the existence of two peaks in the output waveform which are directly traced to the axial demagnetizing field. The dependence of these peaks on the applied field is also shown. Comparison with published data on a thin‐walled toroid is made. A physical description of the reversal mechanism which leads to the two peaks as they result from the axial demagnetizing field is included. Principal conclusions based on the various solutions are as follows: (1) The two‐peak effect is a direct result of the axial demagnetizing field. (2) The damping constant, over the range studied, results in slower switching time as α increases; however, minimum switching as a function of α exists in this model. The higher values of α tend to damp out the two‐peak effect. (3) Increased intensity of the applied field decreases the appearance of the two peaks. (4) Greater values of the saturation magnetization cause the two‐peak effect to be accented, but the switching constant is essentially independent of M.