Method of producing a pole piece with improved magnetic domain structure

Abstract

The mask through which the pole piece is deposited by through mask plating has a yoke region, a narrower pole tip region and a bulb region adjacent the pole tip region. The bulb region results in substantially uniform current density during the through mask plating which results in substantially uniform composition and thickness of the pole piece material across the pole piece. In particular, the composition difference between the pole tip and the yoke region is reduced from that according to prior art techniques. The combination of the composition uniformity and the different (than the prior art) stress distribution in the pole tip material results in favorable domain structure in the pole tip. The magnetic domains formed conduct flux by coherent rotation of the magnetization direction in the domains without changing the location of wall boundaries thereby reducing Barkhausen noise.

Dependencies are inferred from the claim text.