Perpendicular write head with high magnetization pole material and method of fabricating the write head

#This invention relates to magnetic transducers, and more particularly, to write heads for use in disc drives and methods for fabricating such write heads.

#Disc drive write heads for perpendicular recording typically include a soft ferromagnetic yoke that is wrapped around a coil of one or more turns. An electrical current in a coil, produces a magnetic field that aligns the yoke magnetization along the field direction. For perpendicular writing, a soft underlayer is typically employed in the magnetic recording media such that the write field extends between the pole tip and soft underlayer. When the write field exceeds the coercivity and demagnetization field of the media, a domain forms with its magnetization aligned along the write field direction. These domains form the bits of digital data that can be detected by a read head.

#The objective of increasing magnetic storage areal densities requires extremely narrow track-widths in the recording media. The narrowing of the track width will necessarily reduce the cross-sectional area of the writer pole tip. This will increase the yoke reluctance and, consequently, decrease the writer efficiency. A drop in efficiency will require a larger write current. However, the write current cannot be made arbitrarily large without producing undesirable levels of Joule heating. Furthermore, it is difficult and expensive to produce large-amplitude current pulses with fast rise times. In addition, the use of high-moment materials in the writer requires larger write currents to switch the magnetization, in comparison to heads made with softer, lower moment alloys.

#FIG. 1 is a pictorial representation of a disc drive that can use magnetic write heads constructed in accordance with this invention;

#FIG. 2 is a schematic representation of a disc drive write head constructed in accordance with this invention;

#FIG. 3 is a plan view of an intermediate structure formed during fabrication of the top pole of the write head of FIG. 2;

#Referring to the drawings, FIG. 1 is a pictorial representation of a disc drive 10 that can utilize write heads constructed in accordance with this invention. The disc drive includes a housing 12 (with the upper portion removed and the lower portion visible in this view) sized and configured to contain the various components of the disc drive. The disc drive includes a spindle motor 14 for rotating at least one magnetic storage medium 16 within the housing, in this case a magnetic disc. At least one arm 18 is contained within the housing 12, with each arm 18 having a first end 20 with a recording and/or reading head or slider 22, and a second end 24 pivotally mounted on a shaft by a bearing 26. An actuator motor 28 is located at the arm's second end 24, for pivoting the arm 18 to position the head 22 over a desired sector of the disc 16. The actuator motor 28 is regulated by a controller that is not shown in this view and is well known in the art.

#FIG. 2 is a schematic representation of a disc drive write head 30 constructed in accordance with this invention. The write head includes a yoke 32 including a flux return pole 34, also called a bottom pole, and a write pole 36, also called a top pole. A coil 38 or stripline is positioned adjacent to the yoke such that current passing through the coil or stripline induces a magnetic field in the yoke. In operation, the yoke is positioned adjacent to a magnetic medium 40 and separated from the magnetic medium by an air bearing 42. The end of the write pole closest to the magnetic medium is referred to as the air-bearing surface 44. The magnetic medium includes a magnetically hard layer 46 and a magnetically soft layer 48. In accordance with a well known process, a change in the flux in the yoke causes a change in the magnetization of layer 46 in the magnetic medium.

#The top pole includes a layer of insulating material 50, a layer of high moment magnetic material 52 and a layer of lower magnetic moment magnetic material 54. The layer of high moment magnetic material 52 is positioned such that an edge of the material lies adjacent to the air bearing surface. The layer of high moment magnetic material 52 is positioned to be magnetically coupled to the layer of lower moment magnetic material 54. A pedestal 56 of magnetic material, for example NiFe, magnetically couples the layer of lower moment magnetic material 54 to the bottom pole.