Recording head for reducing side track erasure
The present invention relates to a head having an air bearing surface for confronting the surface of a storage medium. The head includes a first pole that is spaced apart from a second pole. At least one non-magnetic spacer is positioned between the first pole and the second pole such that the first pole is magnetically decoupled from the second pole. In a further aspect, one or both of the first pole and the second pole can be elliptical in shape.
Latest Seagate Technology LLC Patents:
- External indicators for adaptive in-field recalibration
- Host-level outer codes
- Air gapped data storage devices and systems
- Increased aerial density capability in storage drives using encoded data portions written to media surfaces with different aerial density capabilities
- Custom initialization in a distributed data storage system
The present invention relates to a recording head, and more particularly but not by limitation to a recording head for a data storage assembly.
BACKGROUND OF THE INVENTIONIn an electronic data storage and retrieval system, a transducing head typically includes a writer for storing magnetically-encoded information on a magnetic disc and a reader for retrieving that magnetically-encoded information from the magnetic disc. The reader typically consists of two shields and a magnetoresistive (MR) sensor positioned between the shields. Magnetic flux from the surface of the disc causes rotation of the magnetization vector of a sensing layer of the MR sensor, which in turn causes a change in electrical resistivity of the MR sensor. This change in resistivity of the MR sensor can be detected by passing a current through the MR sensor and measuring a voltage across the MR sensor. External circuitry then converts the voltage information into an appropriate format and manipulates that information as necessary.
The writer portion typically consists of a top and a bottom pole, which are separated from each other at an air bearing surface of the writer by a gap layer, and which are connected to each other at a region distal from the air bearing surface by a back gap closer or back via. Positioned between the top and bottom poles are one or more layers of conductive coils encapsulated by insulating layers. The writer portion and the reader portion are often arranged in a merged configuration in which a shared pole serves as both the top shield in the reader portion and the bottom pole in the writer portion.
To write data to the magnetic media, an electrical current is caused to flow through the conductive coils to thereby induce a magnetic field across the write gap between the top and bottom poles. By reversing the polarity of the current through the coils, the polarity of the data written to the magnetic media is also reversed. Because the top pole is generally the trailing pole of the top and bottom poles, the top pole is used to physically write the data to the magnetic media. Accordingly, it is the top pole that defines the track width of the written data. More specifically, the track width is defined by the width of the top pole near the write gap at the air bearing surface.
In magnetic recording, it is desirable to improve the areal density at which information can be recorded and reliably read. This desire has led to a trend toward shorter bit length along a magnetic recording track and a shrinking track width. Narrow track widths are achieved by use of narrow pole tips at an air bearing surface (ABS) of the head.
Elements of conventional writers do not properly contain the magnetic flux within the elements themselves and part of the flux leaks into adjacent elements. The result of this leakage is unintentional erasure of side tracks due to the parasitic field established near the susceptible soft under-layer structure within the media. Additionally, the need to increase magnetic recording density results in reducing the size of the read element and shields, causing instability of the domain wall structure. This instability leads to degradation of head performance and increased error rate. Thus, in conventional head designs, there exists increased parasitic affects from the size and shape of the write portion components and reduced magnetic stability of the read portion leading to low head performance and side track erasure.
Therefore, elements of the recording head need to be sized and positioned such that the parasitic field may be reduced or eliminated by improving the spin structure to be less susceptible to dynamic distortion and the read portion needs to provide a more stable magnetic shield having high permeability.
SUMMARY OF THE INVENTIONThe present invention relates to a head having an air bearing surface for confronting the surface of a storage medium. The head includes a first pole that is spaced apart from a second pole. At least one non-magnetic spacer is positioned between the first pole and the second pole such that the first pole is magnetically decoupled from the second pole. In a further aspect, one or both of the first pole and the second pole can be elliptical in shape.
Another aspect of the present invention relates to a head having a read element and first and second read shields positioned on opposite sides of the read element. The first and second shields can be elliptically shaped. In a further aspect, the read shields can be formed by a laminated structure to include alternating ferromagnetic and non-ferromagnetic layers with an anti-ferromagnetic exchange coupling implemented between adjacent ferromagnetic layers.
Yet another aspect of the present invention relates to a magnetic recording head having a write portion including a first pole defining a bearing surface plane and a second pole spaced apart from the first pole to define a gap therebetween. A yoke is coupled to the first pole and positioned between the first pole and the second pole. A read portion includes a read element positioned on a side of the second pole opposite to that of the first pole and a pair of read shields are positioned on opposing sides of the read element. The pair of read shields are spaced apart from the second pole. A non-magnetic shield is positioned between the write portion and the read portion.
Other features and benefits that characterize embodiments of the present invention will be apparent upon reading the following detailed description and review of the associated drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the example shown in
In accordance with the present invention, several configurations for the read/write head carried by slider 110 are described below. Elements of the read/write head can be of different shapes and sizes as well as be positioned differently with respect to other elements.
Additionally, a first spacer 215 is positioned between the yoke 210 and back via 212 and a second spacer 216 is positioned between return pole 208 and back via 212. The first spacer 215 and second spacer 216 can be non-magnetic in order to magnetically decouple the main pole 207 from the return pole 208. The first spacer 215 and second spacer 216 act to reduce distortion of magnetic spin structures of yoke 210 and return pole 208 that can occur due to interactions with back via 212. Additionally, spacers 215 and 216 can prevent magnetic flux leakage from the main is pole 207 to return pole 208. In one embodiment, spacers 215 and 216 can be of any non-magnetic material, including metallic materials such as Ru, Cu, Cr, Au, Ag and/or alloys thereof. The material can also be an insulating material such as aluminum oxide. In the embodiment illustrated, return pole 208 defines a plane 218 that is displaced (recessed) from bearing surface 201. Thus, a greater separation exists between return pole 208 and a corresponding media than the separation between bearing surface 201 and the media. By recessing return pole 208 from bearing surface 201, any magnetic fields emanating from return pole 208 will have a reduced parasitic effect upon the magnetic storage media.
Read portion 204 includes read shields 220 and 222, respectively, which are positioned on opposing sides of a read element 224. In one embodiment, read element 224 can include a giant magnetoresistive stack. Read portion 204 is spaced apart from write portion 202 to reduce magnetic flux leakage from return pole 208 to read portion 204. In one embodiment, gap 206 between write portion 202 and read portion 204 is of a distance greater than the distance from bearing surface 201 to plane 218. In an additional embodiment of the present invention, an electromagnetic shield 226 is located within gap 206, which further protects the read element 224 from any induced current produced by write coil 214 and/or return pole 208. Shield 226 can be a non-magnetic, electrically conductive material to prevent disturbance in operation of read element 224.
In accordance with a further embodiment of the present invention, a read/write head 300 is illustrated in
In accordance with a further embodiment of the present invention, multiple return poles can be used in the write portion of the read/write head. As illustrated in
Portions of the write elements can be of different shapes and sizes in accordance with embodiments of the present invention. As illustrated in
In
Shield 622 includes a first ferromagnetic layer 628, a first anti-ferromagnetic layer 630, a non-magnetic spacer layer 632, a second anti-ferromagnetic layer 634 and a second ferromagnetic layer 636. First and second anti-ferromagnetic layers 630 and 634 are positioned on either side of non-magnetic spacer 632. First ferromagnetic layer 628 and second ferromagnetic layer 636 are coupled to first anti-ferromagnetic layer 630 and second anti-ferromagnetic layer 634, respectively. The anti-ferromagnetic layers 630 and 634 provide an exchange coupling for increased magnetic stability of shield 622.
Shield 624 includes a similar structure to shield 622. Shield 624 includes a first ferromagnetic layer 638, a first anti-ferromagnetic layer 640, a non-magnetic spacer layer 642, a second anti-ferromagnetic layer 644 and a second anti-ferromagnetic layer 646, respectively. The number of layers in the magnetic read shields 622 and 624 can be different depending on total thickness of the shield. In one embodiment, the thickness of a shield can be in a range from about 10 nm to 100 nm. Various materials can also be used for different layers. For example, the ferromagnetic layers can be made of a magnetic material with a low magnetic moment such as NiFe-based alloys. The non-magnetic spacers can be made of Ru, Cu, Cr, Au, Ag and/or alloys thereof. The anti-ferromagnetic layers can be formed of Co or Co-based alloys. Further embodiments may utilize the laminated shield structure for both perpendicular and longitudinal recording applications.
It is to be understood that even though numerous characteristics and advantages of various embodiments of the invention have been set forth in the foregoing description, together with details of the structure and function of various embodiments of the invention, this disclosure is illustrative only, and changes may be made in detail, especially in matters of structure and arrangement of parts within the principles of the present invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. For example, the particular elements may vary depending on the particular application for the magnetic read/write head system while maintaining substantially the same functionality without departing from the scope and spirit of the present invention. In addition, although the preferred embodiment described herein is directed to a magnetic read/write head system for perpendicular recording, it will be appreciated by those skilled in the art that the teachings of the present invention can be applied to longitudinal recording, without departing from the scope and spirit of the present invention.
Claims
1. A recording head comprising:
- a first pole defining a bearing surface;
- a second pole spaced apart from the first pole to define a gap therebetween; and
- at least one non-magnetic spacer positioned between the first pole and the second pole such that the first pole is magnetically decoupled from the second pole.
2. The head of claim 1 wherein the shape of the first pole is elliptical.
3. The head of claim 1 wherein the first pole comprises a rounded portion facing the bearing surface plane and a non-rounded portion opposite the rounded portion.
4. The head of claim 1 and further comprising a yoke positioned between the first pole and the second pole.
5. The head of claim 4 wherein the shape of the yoke is elliptical.
6. The head of claim 4 and further comprising a back via positioned between the yoke and the second pole.
7. The head of claim 6 wherein the shape of the back via is elliptical.
8. The head of claim 6 and further comprising:
- a first non-magnetic spacer positioned between the yoke and the back via; and
- a second non-magnetic spacer positioned between the back via and the second pole.
9. The head of claim 1 wherein the shape of the second pole is elliptical.
10. The head of claim 4 wherein the shape of the second pole is similar to the shape of the yoke.
11. The head of claim 1 wherein the second pole defines a recessed surface plane that is displaced from the bearing surface plane.
12. A head comprising:
- a read element;
- a first read shield positioned on a first side of the read element, wherein the first read shield is elliptically shaped; and
- a second read shield positioned on a second side of the read element, wherein the second read shield is elliptically shaped.
13. The head of claim 12 and further comprising:
- a main pole;
- a yoke coupled to the main pole; and
- a coil positioned such that a current applied to the coil will induce a magnetic field in the main pole and the yoke.
14. The head of claim 13 wherein the coil is positioned between the main pole and the read element.
15. The head of claim 13 wherein the main pole is positioned between the coil and the read element.
16. The head of claim 13 and further comprising a second coil adapted to apply a current in a direction opposite to that of the first-mentioned coil.
17. The head of claim 13 and further comprising:
- a leading pole positioned between the main pole and the read element; and
- a trailing pole positioned on an opposing side of the main pole than the leading pole.
18. The head of claim 17 and further comprising:
- a first anti-ferromagnetic layer positioned between the trailing pole and the main pole to assist in biasing a magnetic field of the main pole; and
- a second anti-ferromagnetic layer positioned between the leading second pole and the main pole to assist in biasing a magnetic field of the main pole.
19. The head of claim 17 and further comprising:
- a first back gap closer coupling the trailing second pole and the main pole; and
- a second back gap closer coupling the leading pole and the yoke.
20. The head of claim 12 wherein each of the first and second read shields further comprises:
- a non-magnetic spacer;
- first and second anti-ferromagnetic layers positioned on opposing sides of the non-magnetic spacer; and
- first and second ferromagnetic layers positioned adjacent to the first and second anti-ferromagnetic layers, respectively.
21. The head of claim 12 wherein the first reader shield and the second reader shield each have an associated magnetic filed gradient that are parallel to each other.
22. A magnetic recording head comprising:
- a write portion comprising: a first pole defining a bearing surface plane; a second pole spaced apart from the first pole; and a yoke coupled to the first pole and positioned between the first pole and the second pole;
- a read portion spaced apart from the write portion and comprising: a read element; and a pair of read shields positioned on opposing sides of the read element; and
- a non-magnetic shield positioned between the read portion and the write portion.
23. The head of claim 22 wherein the first pole, the second pole and the yoke are elliptical in shape.
24. The head of claim 23 and further comprising:
- an elliptically shaped back via positioned between the yoke and the second pole.
25. The head of claim 24 and further comprising:
- a first non-magnetic spacer positioned between the yoke and the back via; and
- a second non-magnetic spacer positioned between the back via and the second pole.
26. The head of claim 22 wherein the size of the second pole is similar to the shape of the yoke.
27. The head of claim 22 wherein the second pole defines a recessed surface plane that is displaced from the bearing surface plane.
28. The head of claim 22 wherein the non-magnetic shield is conductive.
29. The head of claim 22 wherein the shield defines a recessed surface plane that is displaced from the bearing surface plane.
Type: Application
Filed: Jun 30, 2004
Publication Date: Oct 8, 2009
Patent Grant number: 7684150
Applicant: Seagate Technology LLC (Scotts Valley, CA)
Inventors: Taras Pokhil (Arden Hills, MN), Nurul Amin (Woodbury, MN), Steven Bozeman (Savage, MN), Steven Kalderon (Minneapolis, MN), Andrzej Stankiewicz (Edina, MN), Ned Tabat (Chanhassen, MN), Pu-Ling Lu (Rosemount, MN), Johannes Van Ek (Minnetonka, MN), Janusz Nowak (Mahopac, NY), Patrick Ryan (Saint Paul, MN)
Application Number: 10/881,015
International Classification: G11B 5/33 (20060101); G11B 5/147 (20060101);