A Mutual Demagnetizing Tensor for N-Body Magnetic Field Modeling

We introduce a mutual demagnetizing tensor for calculating the demagnetizing field in multiple magnetic bodies. Algorithms for magnetic simulations dealing with interactive n-bodies usually treat the simulation domain as a single magnetized body with embedded nonmagnetic regions. Doing so minimizes the number of variables used in the field calculations but the computation time and storage requirements can become very large. Our approach reduces memory consumption and shows a gain in performance for cases involving field calculation in patterned films. We have verified our results by performing simulation of dots in periodic grids and report a speed-up ranging between 3 × and 10 ×.