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. (C) 2004 American Institute of Physics.