Abstract
Herein, we introduce a classical expression for describing a spin-polarized current, and propose the effect of a spin-polarized current with a spatial distribution in a micromagnetic framework. The electric current was calculated on the basis of the resistance between neighboring cells in the calculation region. The effect of a spin-polarized current crossing a domain wall in a thin and narrow permalloy strip with a notch was elucidated by micromagnetic calculation. When the magnetic strip has a notch, the highest current density around the notch in the magnetic strip is dominant for domain wall motion. The critical current density increases as the notch size increases. Below the critical current, the domain wall tends to vibrate around the notch. The natural frequency of the wall vibration spectrum increases as the notch size increases, whereas it is almost independent of the current density.
