US-12620411-B2 - Writer having laterally decoupled pole sections

US12620411B2US 12620411 B2US12620411 B2US 12620411B2US-12620411-B2

Abstract

An apparatus, in accordance with one aspect of the present invention, includes a writer, having a first write pole having a pole tip extending from a media facing side of the first write pole, and a second write pole having a pole tip extending from a media facing side of the second write pole. A nonmagnetic write gap is positioned between the pole tips of the write poles. A high moment layer is positioned between the write gap and the pole tip of the second write pole. The high moment layer has a higher magnetic moment than a magnetic moment of the pole tip of the second write pole. The high moment layer is segmented into at least two portions by one or more decoupling spacers positioned between adjacent ones of the portions. Another aspect includes an apparatus with an array of such writers.

Inventors

Hugo E. Rothuizen
Stella Brach
Rolf Allenspach
Simeon Furrer
Mark Alfred Lantz
Icko E. T. Iben
Jason Liang

Assignees

INTERNATIONAL BUSINESS MACHINES CORPORATION

Dates

Publication Date: 20260505
Application Date: 20240423

Claims (20)

1 . An apparatus, comprising: a writer, having: a first write pole having a pole tip extending from a media facing side of the first write pole; a second write pole having a pole tip extending from a media facing side of the second write pole; a nonmagnetic write gap between the pole tips of the write poles; and a high moment layer between the write gap and the pole tip of the second write pole, the high moment layer having a higher magnetic moment than a magnetic moment of the pole tip of the second write pole, the high moment layer being segmented into at least two portions by one or more decoupling spacers positioned between adjacent ones of the portions, wherein a first of the portions has a width along a tape facing surface thereof and parallel to the write gap that is less than a width of a second of the portions.
2 . An apparatus as recited in claim 1 , wherein the high moment layer has exactly two portions.
3 . An apparatus as recited in claim 1 , wherein the width of the first of the portions is about 3 μm or less.
4 . An apparatus as recited in claim 1 , wherein the high moment layer has at least three portions.
5 . An apparatus as recited in claim 1 , wherein the high moment layer has at least five portions.
6 . An apparatus as recited in claim 1 , wherein a width of each of the one or more decoupling spacers along a tape facing surface thereof and parallel to the write gap is at least about 50 nm.
7 . An apparatus as recited in claim 1 , wherein a total width of the high moment layer is greater than about 7.5 μm.
8 . An apparatus as recited in claim 1 , wherein the second write pole is comprised of a yoke portion and the pole tip, wherein the high moment layer does not extend along the yoke portion.
9 . An apparatus as recited in claim 1 , comprising a second high moment layer between the write gap and the pole tip of the first write pole, the second high moment layer having a higher magnetic moment than a magnetic moment of the pole tip of the first write pole.
10 . An apparatus as recited in claim 9 , wherein the second high moment layer is segmented into at least two portions by one or more decoupling spacers positioned between adjacent ones of the portions.
11 . An apparatus as recited in claim 1 , wherein the first write pole is a lower write pole, wherein the second write pole is formed above the first write pole.
12 . An apparatus as recited in claim 1 , wherein the second write pole is a lower write pole, wherein the first write pole is formed above the second write pole.
13 . An apparatus as recited in claim 1 , further comprising: a drive mechanism for passing a magnetic medium over the writer; and a controller electrically coupled to the writer.
14 . An apparatus as recited in claim 13 , wherein the drive mechanism is configured to pass the magnetic medium over the write poles in a direction whereby the second write pole is a trailing pole.
15 . An apparatus, comprising: a writer, having: a first write pole having a pole tip extending from a media facing side of the first write pole; a second write pole having a pole tip extending from a media facing side of the second write pole; a nonmagnetic write gap between the pole tips of the write poles; and a high moment layer between the write gap and the pole tip of the second write pole, the high moment layer having a higher magnetic moment than a magnetic moment of the pole tip of the second write pole, the high moment layer being segmented into at least two portions by one or more decoupling spacers positioned between adjacent ones of the portions, wherein the one or more decoupling spacers are formed from a material that is not a ferromagnet.
16 . An apparatus, comprising: an array of writers, each writer having: a first write pole having a pole tip extending from a media facing side of the first write pole; a second write pole having a pole tip extending from a media facing side of the second write pole; a nonmagnetic write gap between the pole tips of the write poles; and a high moment layer between the write gap and the pole tip of the second write pole, the high moment layer having a higher magnetic moment than a magnetic moment of the pole tip of the second write pole, the high moment layer being segmented into at least two portions by one or more decoupling spacers positioned between adjacent ones of the portions, wherein a first of the portions has a width along a tape facing surface thereof and parallel to the write gap that is less than a width of a second of the portions.
17 . An apparatus as recited in claim 16 , wherein a width of each of the one or more decoupling spacers along a tape facing surface thereof and parallel to the write gap is at least about 50 nm.
18 . An apparatus as recited in claim 16 , further comprising: a drive mechanism for passing a magnetic medium over the writers; and a controller electrically coupled to the writers.
19 . An apparatus as recited in claim 16 , wherein the one or more decoupling spacers are formed from a material that is not a ferromagnet.
20 . An apparatus as recited in claim 16 , wherein the high moment layer has at least three portions.

Description

BACKGROUND The present invention relates to data storage systems, and more particularly, this invention relates to apparatuses having improved writer configurations. In magnetic storage systems, magnetic transducers read data from and write data onto magnetic recording media. Data is written on the magnetic recording media by moving a magnetic recording transducer to a position over the media where the data is to be stored. The magnetic recording transducer then generates a magnetic field, which encodes the data into the magnetic media. Data is read from the media by similarly positioning the magnetic read transducer and then sensing the magnetic field of the magnetic media. Read and write operations may be independently synchronized with the movement of the media to ensure that the data can be read from and written to the desired location on the media. An important and continuing goal in the data storage industry is that of increasing the density of data stored on a medium. For tape storage systems, that goal has led to increasing the track and linear bit density on recording tape, and decreasing the thickness of the magnetic tape medium. However, the development of small footprint, higher performance tape drive systems has created various challenges ranging from the design of tape head assemblies for use in such systems to dealing with tape dimensional instability. In a tape drive system, the drive moves the magnetic tape over the surface of the tape head at high speed. Usually the tape head is designed to minimize the spacing between the head and the tape. The spacing between the magnetic head and the magnetic tape is crucial and so goals in these systems are to have the recording gaps of the transducers, which are the source of the magnetic recording flux in near contact with the tape to effect writing sharp transitions, and to have the read elements in near contact with the tape to provide effective coupling of the magnetic field from the tape to the read elements. In a tape drive system, the drive moves the magnetic tape over the surface of the tape head at high speed. Usually the tape head is designed to minimize the spacing between the head and the tape. The spacing between the magnetic head and the magnetic tape is crucial and so goals in these systems are to have the recording gaps of the transducers, which are the source of the magnetic recording flux in near contact with the tape to effect writing sharp transitions, and to have the read elements in near contact with the tape to provide effective coupling of the magnetic field from the tape to the read elements. The quantity of data stored on a magnetic tape may be expanded by increasing the number of data tracks across the tape. More tracks are made possible by reducing feature sizes of the readers and writers, such as by using thin-film fabrication techniques and magnetoresistive (MR) sensors. However, for various reasons, the feature sizes of readers and writers cannot be arbitrarily reduced, and so factors such as tape skew, lateral tape motion (e.g., perpendicular to the direction of tape travel), transients and tape lateral expansion and contraction must be balanced with reader/writer sizes that provide acceptable written tracks and readback signals. One particular problem limiting areal density is misregistration caused by tape lateral expansion and contraction, commonly referred to as poor tape dimensional stability (TDS), or more properly, tape dimensional instability (TDI). Tape lateral contraction and expansion is a well-known phenomenon that occurs due to a plethora of effects, including absorption of water, thermal expansion and contraction, etc. Tape width can vary by up to about 0.1% due to TDS/TDI. When the dimensions of the tape change, various issues arise. During writing, the likelihood of overwriting shingled tracks increases. Overwritten data is often unrecoverable. Likewise, where the width of the tape has changed since the desired data was written, the readers may no longer be positioned over the tracks to be read, increasing reading errors. The extent of misregistration is particularly prevalent toward outer ends of the reader array. More permanent changes in media lateral dimensions may also occur, such as long-term media “creep” (also known in the art as “aging”), which tends to occur over time when a tape is wound around a hub of a tape cartridge. Long-term media creep is particularly problematic when dealing with tape dimensional stability issues, as the two ends of the tape exhibit creep in different ways. The inner wraps of tape positioned closest to the cartridge hub tend to expand laterally over time due to the compressive stresses exerted thereon by the wraps of tape wound around them. Wraps positioned toward the outer diameter of the spool of tape are under less compressive stress, but are under higher tensile stresses, which tends to cause lateral contraction of the tape, i.e., the tape becomes narrower over tim