Reduction of critical current density for domain wall motion in U-shaped magnetic patterns

The critical current density needed for the current-induced domain wall motion ([J.sub.c]) is reduced by decreasing the magnetization ([M.sub.s]) of the free layer film of a U-shaped pattern for a domain wall motion memory. It is shown that the decrease in [M.sub.s] has caused a decrease in the hard axis anisotropy of the pattern and the [J.sub.c] has decreased, which is predicted by a one-dimensional model.