First Approximation to Magnetization Curling in a Chain of Spheres

Abstract

The nucleation field for the magnetization curling mode in an infinite chain of ferromagnetic spheres is calculated as a first-order perturbation on the curling mode in a sphere. To this approximation, the nucleation field dependence on the radius R of the spheres is expressed as a−bR−2 with a, b positive constants. This yields positive nucleation fields for rather small radii (R≥130 Å for iron). To this first approximaton, nucleation by curling is more difficult than by fanning, for R≤100 Å in iron. The packing might influence somewhat the nucleation field, but the dependence is essentially exponential and as such is negligibly small for all practical cases.