A Stoner–Wohlfarth model Redux: Static properties

Recent advances in high-density magnetic storage and spin electronics are based on the combined use of novel magnetic materials with conventional microelectronic materials (metals, insulators and semiconductors). A bit is stored as a magnetization state in some ferromagnetic material (FM) and controlled with an external field to alter the magnetization state. As device size is shrinking steadily toward the nanometer and the need to increase the processing bandwidth prevails, racing toward higher frequencies is getting even more challenging. In magnetic systems, denser storage leads to finer magnetic grains and smaller size leads to single magnetic domain physics. The Stoner–Wohlfarth (SW) model is the simplest model that describes adequately the physics of fine magnetic grains containing single domains and where magnetization state changes by rotation or switching (abrupt reversal). The SW model is reviewed and discussed with its consequences and potential applications in the physics of magnetism and spin electronics.