Reasons were found for the low accuracy of the demagnetizing field in the neighborhood of the corner regions calculated by the previously developed numerical scheme based on the Fredkin-Koehler method, and improved methods were developed. The improvement includes redivision of the computing cells along the boundary of the calculation region, numerical integration of the magnetic potential on the boundary using additional calculation points obtained by Lagrange interpolation, and use of a functional form which approximates the analytic solution of the magnetic potential in the neighborhood of the corners of the calculation region. The improved method was found to decrease the numerical error of the demagnetizing field at the calculation points close to the corners from about 10% to 2.5% in the case of a square prism of an infinite length magnetized along an edge of its cross-section. The effect of improving the demagnetizing field was confirmed by simulating a two-dimensional reversal process in a square prism based on the Landau-Lifshitz-Gilbert equation.
A cross-regulation phenomenon in a multiple-output fly-back converter is analyzed with a circuit simulator and three-dimensional magnetic field FEM software, to determine how the coupling factors of a multiple-winding transformer affect it. The simulated transformer output voltages and their external characteristics coincide with the experimental results. A novel algorithm for designing the configuration of transformer windings is proposed, using circuit and magnetic field simulators.
The thermal stability of the giant magnetoresistance (GMR) effect was examined in Co/Cu multilayers fabricated on various buffer layers with differing interfacial roughnesses and crystallographic orientations. In multilayers on body-centered cubic (BCC)-Cr90Ni10 and (BCC)-Cr80Fe20 buffer layers, the MR ratio is maintained at over 50% up to the annealing temperature of 300°C. On the other hand the MR ratio of the multilayer fabricated on δ-Cr63(Ni-Fe)37 buffer layer and that of the multilayer fabricated with introducing impurity oxygen into the sputtering atmosphere, decreased significantly after the thermal annealing at relatively lower temperature. Secondary ion mass spectroscopy (SIMS) analysis for the multilayer on (BCC)-Cr90Ni10 buffer layer shows a very small amount of atomic diffusion of buffer layer elements into the multilayer after thermal annealing, in comparison with data for multilayers fabricated on a δ-Cr63(Ni-Fe)37 buffer layer. Through detailed structural analysis of the multilayers, it was concluded that the interfacial flatness at grain boundaries should be improved to prevent atomic inter-diffusion and to achieve high thermal stability of the GMR effect in Co/Cu multilayers.