90-DEGREES WALLS IN BULK FERROMAGNETIC MATERIALS

The differential equations for the minimal energy state of a one-dimensional 90-degrees wall in an infinite cubic crystal are used to establish two self-consistency criteria for Ritz models of such a wall, or for its computation. Numerical minimization of the energy is carried out for the physical parameters of Fe, but with various values of M(s). The results show a structure with very little surface charge (a " Neel wall") for rather small M(s). This turns (via some intermediate structures with a mixed charge) to one that has almost only surface charge (a "Bloch wall") for larger M(s) (such as the actual value in Fe).