Magnetization reversal of a pair of interacting linear dipole distributions

Two identical linear dipole distributions are assumed to be localized onto two parallel straight lines; the dipole moment per unit length is assumed to be constant along each line ; the common easy anisotropy axis is normal to these straight lines and lies in their common plane. The coercive field of the pair is identical with the coercive field of one dipole line, and the reversal mode is fanning. If the pair is initially parallel and a magnetic field opposite to its direction is applied to only one dipole, the effective coercivity which results is larger and increases for decreasing distance between the linear dipoles. The reversal mode is fanning; nevertheless the final configuration can be antiparallel, i.e., with reversal of only the dipole subjected to the field. This configuration remains stable after removal of the field if and only if the dipoles are far enough apart the minimum distance can be related to the transition length in digital recording.