Fields external to open-structure magnetic devices represented by ellipsoid or spheroid

The mathematical expressions for the field intensities external to spheroids or an ellipsoid with uniform magnetization are given. They are useful in predicting fields external to (a) open-structure magnetic devices such as metallic or ferrite films, twistors or splinters, and (b) spheroidal and ellipsoidal samples which are often used in magnetic measurements. Curves are plotted to indicate the spatial variation of field intensity with the dimensional ratio of a spheroid as a parameter. In the region near the spheroid, field intensity is normalized against field intensity at the boundary. In the region far from the spheroid, field intensity is normalized against that of a dipole of the same dipole strength as the spheroid.