Journal of Geophysical Research -- June 10, 1993 -- Volume 98, Issue B6, pp. 9551-9556

A generalization of the demagnetizing tensor for nonuniform magnetization

Andrew J. Newell

Geophysics Laboratory, Department of Physics, University of Toronto, Ontario, Canada

Wyn Williams

Department of Geology and Geophysics, University of Edinburgh, Edinburgh, Scotland

David J. Dunlop

Geophysics Laboratory, Department of Physics, University of Toronto, Ontario, Canada

The demagnetizing tensor for ferromagnets is generalized to include interactions between uniformly magnetized bodies. This ``mutual'' demagnetizing tensor is symmetric, has a trace of zero, and has other simple geometric properties. The tensor is then used to develop an expression for the macroscopic magnetic field in non-uniformly magnetized bodies of arbitrary shape. Finally, the theory is applied to a block model of magnetization and explicit formulae for the tensor components are given. © American Geophysical Union 1993