A magneto-fluidic seal includes a shaft; a sleeve surrounding the shaft; a
housing made of soft magnetic material surrounding the sleeve; a magnet
conducting a magnetic flux to the sleeve; and a magnetic fluid in a gap
between the sleeve and the shaft, and/or in a gap between the sleeve and
the housing. Optionally, the sleeve includes a channel on a longitudinal
side, and wherein the magnet is positioned in the channel. The channel
can be substantially circular or polyhedral. The magnet is preferably
offset from a bottom of the channel, and oriented radially. Preferably,
the magnet includes a plurality of segments, or flat plate-shaped
magnets, arranged substantially evenly and circumferentially around the
shaft.