On the computation of the demagnetization tensor for uniformly magnetized particles of arbitrary shape. Part II: numerical approach

In Part I, we described an analytical approach to the computation of the demagnetization tensor field for a uniformly magnetized particle with an arbitrary shape. In this paper, Part 11, we introduce two methods for the numerical computation of the demagnetization tensor field. One method uses a Fourier space representation of the particle shape, the other starts from the real space representation. The accuracy of the methods is compared to theoretical results for the demagnetization tensor of the uniformly magnetized cylinder with arbitrary aspect ratio. Example computations are presented for the hexagonal plate, the truncated paraboloid, and a so-called "Pac-Man" shape, recently designed for MRAM applications. Finally, the magnetostatic self-energy of a uniformly magnetized regular polygonal disk of arbitrary order is analyzed. A linear relation is found between the order of the polygon and the critical aspect ratio for in-plane vs. axial magnetization states. (C) 2003 Elsevier B.V. All rights reserved.