About cookies on this site Our websites require some cookies to function properly (required). In addition, other cookies may be used with your consent to analyze site usage, improve the user experience and for advertising. For more information, please review your options. By visiting our website, you agree to our processing of information as described in IBM’sprivacy statement. To provide a smooth navigation, your cookie preferences will be shared across the IBM web domains listed here.
Publication
J Magn Magn Mater
Paper
Force, momentum and topology of a moving magnetic domain
Abstract
The following general relations involving force, momentum and topological winding number of a translating magnetic domain are derived from the Landau-Lifshifz equation in a context appropriate to bubbles: The gyrotropic force tending to deflect a steadily moving domain is proportional to a mean winding number linear in Bloch-point coordinates. The time derivative of the canonical momentum for a domain of integer winding number is equal to the total force, which must include gyrotropic and dissipative terms. A new contour integral expresses the momentum in the limit of vanishing wall thickness. Approximate equations of quasi-steady domain motion are cast into a form resembling Hamiltion's equations for a particle. Discussion centers on applications to gradientless propagation, bubble saturation velocity, and the Blochline model of inertial effects, and on general limitations of the theory. © 1979.