US Patent 7015780 Apparatus, device and method for generating magnetic field gradient

A monolithic or dual monolithic magnetic device or apparatus having an array of formations such as protruding or raised nubs wherein adjacent nubs have the same or opposite polarity to produce a high magnetic field gradient in the vicinity of the nubs is described. In lieu of nubs, the use of a magnetic device with thru-holes, blind holes, filled holes, or iron flux concentrators is also detailed, wherein all embodiments result in regions of high magnetic field gradient. Apparatus and methods for spot-poling a magnet array are also illustrated.