New Types of Three-Dimensional Vortices in the Heisenberg Model

The Heisenberg model for an isotropic magnet is considered in this work. A substitution that reduces the corresponding equations to equations with a simpler geometric interpretation is applied. One of the solutions of the latter describes a new magnetic structure comprised of two straight intersecting vortex filaments, which change the topological charge after intersection.

Stoner-Wohlfarth Model for Nanocrystalline Anisotropic Sm2Co17 Magnets

The Stoner-Wohlfarth model can be used for predicting hysteresis curves of either isotropic or anisotropic nanocrystalline Sm2Co17 type magnets. For isotropic magnets, with Mr/Ms=0.5, the Stoner-Wohlfarth model predicts coercive force of 48% of the anisotropy field. Here, Mr is remanence and Ms is magnetization of saturation. Two texture distributions were compared: Pearson VII and cosn. The calculations indicate that increasing the alignment degree of the grains, the coercivity increases. However, this increase of the coercive force is small. It is found that a very well aligned magnet, with Mr/Ms ratio of 0.96, presents coercivity only ~20% higher than that of the isotropic magnet.