PMR writer device with multi-level tapered write pole

#1. Field of the Invention

#This invention relates generally to magnetic recording heads, particularly to perpendicular recording heads that produce recording magnetic fields that are substantially perpendicular to the recording medium. More specifically, the invention relates to a tapered shape of a magnetic pole of a recording head that allows a more efficient delivery of a magnetic recording field to a recording medium.

#2. Description of the Related Art

#FIG. 1a is a schematic representation of side view of an exemplary prior art PMR having a single main pole.

#FIG. 1b is a schematic top view of the same PMR showing the shape of the main pole.

#FIGS. 2a, 2b and 2c are prior art schematic representations showing exemplary main poles attached to top (2a), bottom (2b) and top and bottom (2c) yokes, so that the edges of the yokes are recessed from the pole tips.

#The preferred embodiment of the present invention is a multi-level tapered write pole structure for use within a perpendicular magnetic recording (PMR) head. A first level of the tapering (i.e. an increasing thickness in the layer produced by a bevel) begins at the ABS edge of the pole tip (this is called the 1st taper) and extends in the positive y-direction (away from the ABS). The 1st taper ends and the pole layer then retains a constant maximum thickness from that point backwards (i.e., away from the ABS). A second level of tapering begins at the edges of the upper and/or lower yoke structure (2nd taper) which contacts the pole tip on the constant thickness portion of either a top surface or a bottom surface and proceeds in the positive y-direction until the yoke layer attains a constant thickness.

#Referring to FIG. 4a, there is shown a schematic drawing of a side-view cross-section of a double-level tapered write pole that is a preferred embodiment of the present invention. In this embodiment, the main pole (14) is sandwiched between a top yoke (17a) and a bottom yoke (17b) that are formed conformally on the main pole on its trailing (top) and leading (bottom) surfaces respectively. The top yoke (17a) is formed on the top surface (trailing surface) of the main pole; the bottom yoke (17b) is formed on the bottom surface (leading surface) of the main pole. This particular configuration is reflection-symmetric about a z-y mid-plane passing through the mid-line (shown as a dashed line) of the main pole.

#The taper of the main pole is defined by a region of symmetrically (about said z-y mid-plane) increasing thickness in the direction away from (i.e. in the positive y-direction defined in FIG. 1a)) the ABS end of the main pole (19). The taper terminates at a back edge (21), from which edge distally backwards, the main pole remains flat and horizontal and the thickness of the pole remains constant as the pole extends away from the ABS. Note, the direction away from the ABS of the pole tip may be referred to hereinafter, with equal accuracy, as the distal direction or the positive y-direction.