Magnetic recording head having a plurality of shield layers

Provided is a magnetic recording head including a return pole, a writing pole spaced by a predetermined distance from the return pole, an induction writing coil for inducing a magnetic field to be formed across the writing pole, and a plurality of shield layers formed on the writing pole. Accordingly, magnetic fields generated inside and outside the magnetic recording head are prevented from concentrating on the return pole, and information is effectively written on and erased from an information recording media.

BACKGROUND OF THE INVENTION

This application claims the priority of Korean Patent Application No. 2003-65223, filed on Sep. 19, 2003, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.

1. Field of the Invention

The present invention relates to a magnetic recording head, and more particularly, to a magnetic recording head, which includes a plurality of shield layers formed on a writing pole to prevent magnetic fields generated inside and outside the magnetic recording head from concentrating on a return pole and to effectively write and erase information on an information recording media.

2. Description of the Related Art

Studies of a perpendicular magnetic recording method are actively performed all over the world to increase a recording density in a magnetic information recording field. In the perpendicular magnetic recording method, magnetization is oriented perpendicular to a disk surface to increase a recording density, unlike a general longitudinal magnetic recording method. The perpendicular magnetic recording method writes information using a writing pole.

FIG. 1is a perspective view of a conventional magnetic read/write head in an apparatus for writing and reading a magnetic signal on a predetermined recording media, such as a hard disk drive (HDD). As shown inFIG. 1, a magnetic head10is installed on a slide12disposed on one end of a swing arm11, and is moved to a desired position over a recording media by pivoting of the swing arm11to perform write and read operations.

FIG. 2is an enlarged view of the magnetic head20shown inFIG. 1. As shown inFIG. 2, the magnetic head20includes a magneto-resistive head21for a read operation and a magnetic recording head for a write operation. The magneto-resistive head21detects and reads a magnetic signal recorded on the recording media. The magnetic recording head includes a writing pole22for forming leakage magnetic flux to the recording medium, a return pole23, and a writing coil24acting as a current supply route, and records a magnetic signal of a desired content on the recording media.

In particular, the magnetic recording head determines the quality of a signal input to the recording media. If the signal input via the magnetic recording head is not clean, the magneto-resistive head cannot perform satisfactory reproduction although it has an excellent performance. The magnetic recording head is very sensitive to an external magnetic field. For example, a magnetic field from a voice coil motor (VCM) that drives the swing arm11is introduced to the magnetic recording head, an undesired external magnetic field concentrates on the magnetic recording head. This phenomenon is referred to as an antenna effect. The external magnetic field concentrating on the magnetic recording head causes wrong information to be written on the recording media or information on the recording media to be erased.

FIG. 3Aillustrates the flow of a magnetic field when information is written on an information recording media, such as a HDD, using a magnetic recording head.

A conventional magnetic recording head30includes a return pole32, a writing pole33spaced by a predetermined distance from the return pole32, an induction writing coil34for forming a magnetic field across the writing pole33, and a shield layer35formed on the writing pole33. The writing pole33writes information on an information recording media31that is generally formed by depositing a writing layer on a soft magnetic layer. As shown inFIG. 3A, a magnetic field that moves from the writing pole33and passes through the return pole32and the shield layer35forms an oval shape. If a magnetic field passing through the return pole32in a magnetic recording head without the shield layer35becomes larger, the magnetic field causes a noise to the recording media. To prevent the noise, the shield layer35is formed on the writing pole33so that part of the magnetic field flowing toward the return pole32can be distributed to the shield layer35, and thus, the strength of the magnetic field directed toward the return pole32can be reduced.

When magnetic writing is performed, magnetic flux from the writing pole33separately flows to the return pole32and the shield layer35. Here, since the return pole32is not magnetically connected to the writing pole33, the magnetic flux flowing toward the return pole32decreases relatively, and the magnetic flux flowing toward the shield layer35increases. If a large amount of magnetic flux flows to the shield layer35, the large amount of magnetic flux causes a noise that obstructs writing, thereby reducing the effect of the shield layer35.

FIG. 3Billustrates the flow of a magnetic field generated by an external magnetic field source, such as the swing arm or the VCM for driving the swing arm, other than the magnetic recording head30. The magnetic flux concentrates on an end of the writing pole33due to structural characteristics of the writing pole33and a large amount of magnetic flux flows through the writing pole33. The large amount of magnetic flux causes a noise when the information recording media31performs writing. The shield layer35is employed to reduce the influence of the external magnetic field.

However, the shield layer35formed on the writing pole33has a limitation in reducing the adverse effects of the magnetic fields generated inside and outside the magnetic recording head30as shown inFIG. 3AandFIG. 3B, respectively. That is, the shield layer35hardly reduces the influence of the external magnetic field on the writing pole33, such that the external magnetic field affects and still obstructs the writing function of the writing pole33. Although the external magnetic field generated outside the magnetic recording head30is small, the external magnetic field at the writing pole33becomes larger sharply due to a bottleneck.

SUMMARY OF THE INVENTION

The present invention provides a magnetic recording head, which disperses magnetic flux that flows to a single-layer shield portion during a perpendicular magnetic recording process to reduce a magnetic field that causes a noise of a recording media at the single-layer shield portion.

The present invention also provides a magnetic recording head, which disperses an external magnetic field that flows to a writing pole to prevent the external magnetic field from concentrating on the writing pole and obstructing information writing.

According to an aspect of the present invention, there is provided a magnetic recording head comprising: a return pole; a writing pole spaced by a predetermined distance from the return pole; an induction writing coil for inducing a magnetic field to be formed across the writing pole; and a plurality of shield layers formed on the writing pole.

The plurality of shield layers may be made of a magnetic material, and each insulation layer may be formed between adjacent shield layers of the plurality of shield layers to separate the adjacent shield layers.

Among the plurality of shield layers, a magnetic permeability of a lower shield layer may be less than or equal to a magnetic permeability of an upper shield layer.

Among the plurality of shield layers, a width of a leading end of a lower shield layer may be less than or equal to a width of a leading end of an upper shield layer.

Leading ends of the plurality of shield layers may be aligned with a leading end of the writing pole.

The insulation layer formed between the adjacent shield layers may extend from leading ends of the adjacent shield layers to predetermined portions of tailing ends of the adjacent shield layers.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be described more fully with reference to the accompanying drawings, in which preferred embodiments of the invention are shown.

FIG. 4Ais a front view of a magnetic recording head according to the present invention. Referring toFIG. 4A, a multi-layered structure for writing and reading information is formed on a substrate41. Here, since a magneto-resistive head42is simply shown because it has the same structure as a conventional magneto-resistive head. The magneto-resistive head42is formed on the substrate41, and a return pole43made of a magnetic material is formed on the magneto-resistive head42. A writing pole44is formed over the return pole43, and a first shield layer45and a second shield layer47are formed on the writing pole44to be spaced by a predetermined distance from the writing pole44. An insulation layer46is interposed between the first shield layer45and the second shield layer47.

FIG. 4Bis a side sectional view of the magnetic recording head shown inFIG. 4A. Referring toFIG. 4B, the writing pole44is spaced by the predetermined distance from the return pole43, and the first shield layer45and the second shield layer47are formed on the writing pole44. The insulation layer46is formed between the first shield layer45and the second shield layer47to magnetically separate the first shield layer45from the second shield layer47. An induction writing coil48for writing information is formed between the writing pole44and the first shield layer45. Here, there are no limitations in the position of the induction writing coil48, and the induction writing coil48may also be formed between the return pole43and the writing pole44. A plating pole49may be further formed under the writing pole44.

FIGS. 4A and 4Billustrate an example where the two shield layers, that is, the first shield layer45and the second shield layer47, are formed on the writing pole44. However, according to the magnetic recording head of the present invention, shield layers more than two shield layers may be formed on the writing pole44. Each insulation layer46is formed between adjacent shield layers45and47of the plurality of shield layers. The insulation layer46does not extend up to tailing ends of the shield layers45and47, but extends from leading ends of the shield layers45and47, i.e., the substrate41to predetermined portions of the tailing ends. That is, the leading ends of the shield layers45and47are magnetically separated by the insulation layer46. However, the tailing ends of the shield layers45and47are magnetically connected, thereby effectively configuring a magnetic circuit where internal and external magnetic fields diverge, not converge. However, the present invention is not limited thereto.

In the present invention, the lower shield layer, that is, the first shield layer45, is made of a material having a magnetic permeability similar to that of the upper shield layer, that is, the second shield layer47. However, it is preferable that the magnetic permeability and size of the first shield layer45be equal to or less than those of the second shield layer47. If the lower and upper shield layers45and47have the same magnetic permeability and size during the operation of the magnetic recording head, densities of internal and external magnetic fields flowing toward the lower shield layer45become greater than those flowing toward the upper shield layer47.

FIG. 5Aillustrates the flow of a magnetic field when information is written on an information recording media51using a magnetic recording head50according to the present invention. Since a return pole52is not magnetically connected to a writing pole53, most of magnetic flux from the writing pole53flows to a first shield layer55and a second shield layer57. Then, magnetic fields flowing through the shield layers55and57do not demagnetise a magnetic field generated across the writing pole53and do not affect writing of the writing pole53. Here, if the first shield layer55has a magnetic permeability and a width less than those of the second shield layer57, the magnetic fields flowing through the first shield layer55and the second shield layer57can be controlled to distribute similarly.

FIG. 5Bis the flow of a magnetic field generated by an external magnetic field source outside the magnetic recording head50shown inFIG. 5A. As shown inFIG. 5B, the magnetic field generated by the external magnetic field source is expanded through the magnetic recording head50to the information recording media51. That is, the magnetic field flows through the return pole52, the writing pole53, the first shield layer55, and the second shield layer57to the information recording media51. In this way, since two or more shield layers are formed and the external magnetic field that flows to the writing pole53is dispersed to the plurality of shield layers, the influence of the external magnetic field on the writing pole53can be reduced.

FIGS. 6A through 6Dare schematic views illustrating a method of manufacturing a magnetic recording head according to the present invention. The method forms a plurality of shield layers on a typical magnetic recording head, and other operations of the method are not much different from a conventional method of manufacturing a magnetic recording head.

Referring toFIG. 6A, a plating pole62and a writing pole63are formed. Referring toFIG. 6B, a part of an insulation layer66made of an insulating material is formed, a writing coil64is installed on the insulation layer66, and a remaining insulating material is applied to the resultant structure to completely form the insulation layer66. Referring toFIG. 6C, a magnetic material is deposited through sputtering or the like to form a first shield layer65. Referring toFIG. 6D, an insulation layer66′ is formed on a predetermined portion of the first shield layer65, and a second shield layer made of a magnetic material is formed on the resultant structure.

Here, the materials of the insulation layers66and66′ are non-magnetic materials, for example, aluminium oxide (Al2O3) or silicon dioxide (SiO2). The insulation layer66′ formed on the first shield layer65does not extend over the entire surface of the first shield layer65, but extends from a leading end of the first shield layer65to a predetermined portion of a tailing end of the first shield layer65. This is because tailing ends of the first shield layer65and the second shield layer67contact each other to induce a magnetic field to flow smoothly to the second shield layer67.

FIG. 7is a graph for comparing perpendicular and longitudinal magnetic fields from a conventional perpendicular magnetic recording head and a perpendicular magnetic recording head according to the present invention through electromagnetic field analysis. Here, the horizontal axis of the graph denotes a distance, from a return pole to a shield layer, of a leading end of a magnetic recording head that faces an information recording media. That is, the return pole is formed in an area of 0 to 3 μm of the horizontal axis, a writing pole is formed in an area of 5 to 6 μm, and the shield layer is formed in an area greater than 6 μm. Original head denotes a conventional magnetic recording head, and Split head denotes a magnetic recording head according to the present invention. It can be seen that in the area greater than 6 μm, a perpendicular magnetic field in the magnetic recording head of the present invention decreases more than the conventional magnetic field. That is, since the magnetic recording head according to the present invention includes two or more shield layers formed on the writing pole, the flow of the magnetic field is dispersed and reduced more than the conventional magnetic recording head that includes no shield layer or only one shield layer.

FIG. 8is a graph for comparing a strength of a magnetic field generated by an external magnetic field in a conventional magnetic recording head with a strength of a magnetic field generated by an external magnetic field in a magnetic recording head according to the present invention through electromagnetic field analysis. Here, the graph illustrates a strength versus a distance from the return pole to the shield layer. As shown inFIG. 8, the magnetic recording head where two or more shield layers are formed on the writing pole is less influenced by the external magnetic field than the conventional magnetic recording head over all the return pole area of 0 to 3 μm, the writing pole area of 5 to 6 μm, and the shield layer area greater than 6 μm.

According to the present invention, when the perpendicular magnetic recording is performed using the magnetic fields generated inside and outside the magnetic recording head, the magnetic flux flowing toward the single-layer shield portion is dispersed to effectively reduce a noise of the magnetic recording head caused by the magnetic fields. Further, the externally generated magnetic field is prevented from concentrating on the writing pole and obstructing the writing of information, thereby effectively dispersing the magnetic field that flows to the writing pole.

As a result, information can be effectively recorded on and erased from the information recording media.