A Dynamic Large Signal Model for a Single-Domain Thin Magnetic Film Inductor

A dynamic large signal model for a thin film inductor consisting of two orthogonal windings wound around a thin single-domain film is developed. Based on Gilbert's modification of the Landau-Lifshitz equation describing the rotational behavior of the magnetization of the film, this model is valid for both large and small signals and for frequencies up to several hundred megacycles. As a result of the gyroscopic nature of mangetic behavior, the model of necessity contains as a part of its description a nonlinear second order differential equation in time. Until the external circuits connected to the inductor are specified, one cannot explicitly relate magnetic behavior and terminal voltages and currents. Instead one must seek a simultaneous solution of the differential equations describing the interconnected system. The utility of this model for analytically describing the behavior of thin film parametric devices such as parametrons, parametric amplifiers, balanced modulators, and flip-flops is mentioned but not discussed in detail.