Effect of Lattice Defects on the Magnetization Curve of Ferromagnets

Abstract

This paper presents a theoretical treatment of the action of internal stresses on domain walls and on uniformly magnetized Weiss domains. The theory is based on micromagnetics, dislocation theory, and probability theory. Experimental results on the domain structure, the temperature dependence of the reversible susceptibility, and the coercive field of plastically deformed nickel, cobalt, and silicon-iron single crystals and neutron-irradiated nickel single crystals are discussed on the basis of the theory. The experiments are interpreted in terms of the magneto-elastic interaction between dislocations and magnetization and agree satisfactorily with the theoretical predictions. The observed variations of the domain structure during the magnetization process can be accounted for in terms of the theory of phases (Néel, Lawton, and Stewart) and the mobility of the domain walls.