An accurate and efficient 3-D micromagnetic simulation of metal evaporated tape

Metal evaporated tape (MET) has a complex column-like structure in which magnetic domains are arranged randomly. In order to accurately simulate the behaviour of MET it is important to capture these aspects of the material in a high-resolution 3-D micromagnetic model. The scale of this problem prohibits the use of traditional scalar computers and leads us to develop algorithms for a vector processor architecture. We demonstrate that despite the materials highly non-uniform structure, it is possible to develop fast vector algorithms for the computation of the magnetostatic interaction field. We do this by splitting the field calculation into near and far components. The near held component is calculated exactly using an efficient vector algorithm, whereas the far field is calculated approximately using a novel fast Fourier transform (FFT) technique. Results are presented which demonstrate that, in practice, the algorithms require sub-O(N log(N)) computation time. In addition results of highly realistic simulation of hysteresis in MET are presented.