Calculation of demagnetizing field by means of FFT

The demagnetizing field due to magnetization prescribed on a set of Cartesian mesh points in a flat film is solved by means of the Fast Fourier Transform (FFT). First, the magnetization and the magnetostatic potential are Fourier transformed over planes parallel to the film. Integration of the boundary value problem for the potential in the transform functional space is then carried out across the thickness facilitated by a recurrence formula. Finally, the demagnetizing field may be Fourier represented. © 1978.