The Theory of the Ferromagnetic Anisotropy of Single Crystals

Abstract

It is well known that in single crystals of iron and nickel the direction of magnetization is not generally parallel to the direction of the magnetic field, although these crystals belong to the cubic system. When the magnetization in a crystal has a certain value as measured in the direction of the field, there will be also, in general, a component of magnetization measured in the direction at right angles. This paper describes the calculation according to the domain theory, of the normal component of magnetization, using certain assumptions which are almost identical with those used by Heisenberg in his calculation of the magnetostriction of iron crystals. Theoretical curves are shown for a variety of crystallographic directions. Each of these curves shows all of the possible positions and magnitudes of the vector representing the magnetization in iron crystals as the magnetic field parallel to any given direction in the crystal increases in strength from zero to a high value. The theoretical curves are compared with the experimental curves of Honda and Kaya, and show good agreement with them.