Internal Field, Dispersion, Creeping, and Switching Speed of Coupled Films

Coupled films were made either by sandwiching striplines between two films on different substrates, or by multilayer evaporation. The first structure was found to be inadequate in reducing the demagnetizing field because the airgap was appreciable. The switching speed of coupled films was calculated with the Landau-Lifshitz equation, taking into account the magnetostatic coupling energies. Nearly identical rotational switching speeds were found for single and coupled films. The results were verified by measurements. Skew, dispersion, and creeping were measured. It was found that coupled films were less susceptible to the word field disturb from neighboring lines. It was also found that the orthogonal drive scheme could be realized, using coupled films with small diameter and large thickness, which would prevent their use as single films.