Spin Configuration and Intrinsic Coercive Field of Narrow Domain Walls in Co₅R‐Compounds

Abstract

Abstract In ferromagnetic materials with large anisotropy constants ( K 1 > 10 8 erg/cm 3 ) the domain wall width, δB, is of the order of magnitude of a few lattice constants (10 to 30 Å). The spin configuration of such 180°‐walls in Co 5 R‐compounds is determined within the framework of the Heisenberg model. It is found that the deviations from the micromagnetic solution occur mainly in the centre of the wall. The wall energy was found to depend periodically on the position of the wall centre with respect to the crystal lattice. The oscillations of the wall energy give rise to a coercive field H c = const ( A/D ) exp [– π δ B / D ] (A exchange constant, D wavelength perpendicular to the domain wall). The possibilities to obtain large intrinsic coercive fields are discussed in some detail.