A permanent magnet in which the magnetization direction varies with location
to
optimize or restrict a magnetic field property in a selected direction at a selected
point. The magnetic field property may be, for example, the transverse magnetic
field, axial magnetic field, axial gradient of the transverse magnetic field, transverse
gradient of the transverse magnetic field, axis gradient of the axial magnetic
field, transverse gradient of the axial magnetic field, the product of the transverse
magnetic field and the transverse gradient of the transverse magnetic field, the
product of the transverse magnetic field and the axial gradient of the transverse
magnetic field, the product of the axial magnetic field and the transverse gradient
of the axial magnetic field, or the product of the axial magnetic field and the
axial gradient of the axial magnetic field. The magnet may be formed of one or
more segments in which the magnetization direction varies smoothly and continuously,
or the magnet may be formed of a plurality of segments in which the magnetization
direction is constant. A method of making and using such magnets is also disclosed.