Dynamic FE simulation of μMAG standard problem No. 2 (invited)

mu MAG standard problem No. 2 was studied using a three-dimensional finite element simulation based on the solution of the Gilbert equation. Asymptotic boundary conditions were imposed in order to compute the demagnetizing fields and a Gilbert-damping parameter (alpha = 1.0) was used to drive the system towards equilibrium. The coercivities observed for the thin elongated platelet on which standard problem No. 2 is based show a slight dependence on its size. The width of the particle was varied from 1 to 30 times the exchange length while keeping the aspect ratio of 5:1:0.1 unchanged. An external field is applied parallel to the [111] direction, giving values of the coercive field ranging from -0.056 to -0.04 in units of the saturation magnetization M-s. With the external field applied parallel to the long axis of the particle a strong dependence of the coercivity on its size is found which can be attributed to different reversal mechanisms. (C) 1999 American Institute of Physics. [S0021-8979(99)28308-9].