Magnetization chirality due to asymmetrical structure in Ni-Fe annular dots for high-density memory cells

Ni–Fe asymmetric ring dots with partially planed outer sides were investigated as candidates for high-density magnetic memory cells. The magnetic states, which were measured with magnetic force microscopy, show that in-plane magnetic fields can control the chirality, either clockwise or counterclockwise, of vortical magnetizations of the Ni–Fe asymmetric ring dots. This control facilitates applying ring dots to the magnetic random access memories.