1. Field of the Invention
The present invention relates to a magnetic head preferably utilized in a recording medium drive such as a hard disk drive.
2. Description of the Prior Art
A magnetic pole end layer is formed on the surface of a lower magnetic pole in an inductive magnetic head, for example. A non-magnetic gap layer is interposed between the magnetic pole end layer and an upper magnetic pole. A magnetic coil is located between the upper magnetic pole and the lower magnetic pole. The magnetic coil generates a magnetic field in response to supply of electric current to the magnetic coil. The non-magnetic gap layer serves to leak a magnetic flux running between the upper and lower magnetic poles out of a medium-opposed surface. The leaked magnetic flux forms a magnetic field for recordation. The magnetic field for recordation is applied to the magnetic recording disk. This results in a change in the direction of magnetization in the magnetic recording disk. Binary data is in this manner written onto the magnetic recording disk.
The inductive magnetic head desirably enjoys a reduced inductance. A reduction in the inductance of the inductive magnetic head contributes to a reliable realization of a high-frequency recordation. A reduction in the inductance requires a reduction in the length of the flux path of the magnetic coil as well as a reduction in the turns of the magnetic coil, for example. However, a reduction in the length of the flux path of the magnetic coil inevitably leads to the smaller sectional area of the magnetic coil. The smaller sectional area causes a deteriorated magnitude of the magnetic field for recordation. A reduction in the turns of the magnetic coil also causes a deteriorated magnitude of the magnetic field for recordation.
It is accordingly an object of the present invention to provide a magnetic head of a reduced inductance.
According to the present invention, there is provided a magnetic head comprising: a first magnetic pole extending backward from its front end exposed at a medium-opposed surface; a second magnetic pole extending backward from its front end exposed at the medium-opposed surface, the second magnetic pole magnetically connected to the first magnetic pole at a position backward from the front end of the second magnetic pole; a magnetic pole end layer having the front end exposed at the medium opposed surface, the magnetic pole end layer opposed to the second magnetic pole in a space between the first and second magnetic poles; at least one magnetic piece located between the magnetic pole end layer and the first magnetic pole so as to connect the magnetic pole end layer and the first magnetic pole to each other along the medium-opposed surface; and a non-magnetic material located between the magnetic pole end layer and the first magnetic pole to fill a space between the magnetic pole end layer and the first magnetic pole along the medium-opposed surface.
The magnetic head allows the magnetic pole end layer and the magnetic piece or pieces to exist between the first and second magnetic poles. The magnetic piece or pieces are located between the magnetic pole end layer and the first magnetic pole. When magnetic bit data is to be written, a magnetic flux runs through the first magnetic pole, the magnetic piece or pieces, the magnetic pole end layer and the second magnetic pole. The magnetic pole end layer is opposed to the second magnetic pole between the first and second magnetic poles. The magnetic flux is leaked out of the medium-opposed surface between the first and second magnetic poles. The leaked magnetic flux forms a magnetic field for recordation. Magnetic bit data is in this manner written onto a magnetic recording medium, for example.
The magnetic head allows the non-magnetic material to exist between the magnetic pole end layer and the first magnetic pole. The non-magnetic material fills a space between the magnetic pole end layer and the first magnetic pole along the medium-opposed surface. The non-magnetic material contributes to a reduction in the volume of a magnetic body between the magnetic pole end layer and the first magnetic pole as compared with the case where a magnetic body fills the entire space between the magnetic pole end layer and the first magnetic pole. The volume of the magnetic body is reduced in the magnetic head. The flux path of the magnetic flux can be narrowed. The narrowed flux path contributes to a reduction in the inductance of the magnetic head. A reduced inductance enables a reliable high-frequency recordation. Furthermore, as long as the magnetic pole end layer has a width equal to the width of a conventional magnetic pole end layer, the magnetic field for recordation of a conventional magnitude can be maintained based on the magnetic flux running between the second magnetic pole and the magnetic pole end layer.
The magnetic head can be incorporated in a storage medium drive. The storage medium drive may comprise: an enclosure; and a magnetic head enclosed in the enclosure, for example. In this case, the magnetic head comprises: a first magnetic pole extending backward from its front end exposed at a medium-opposed surface; a second magnetic pole extending backward from its front end exposed at the medium-opposed surface, the second magnetic pole magnetically connected to the first magnetic pole at a position backward from the front end of the second magnetic pole; a magnetic pole end layer having the front end exposed at the medium opposed surface, the magnetic pole end layer opposed to the second magnetic pole in a space between the first and second magnetic poles; at least one magnetic piece located between the magnetic pole end layer and the first magnetic pole so as to connect the magnetic pole end layer and the first magnetic pole to each other along the medium-opposed surface; and a non-magnetic material located between the magnetic pole end layer and the first magnetic pole to fill a space between the magnetic pole end layer and the first magnetic pole along the medium-opposed surface.
The above and other objects, features and advantages of the present invention will become apparent from the following description of the preferred embodiment in conjunction with the accompanying drawings, wherein:
At least one magnetic recording disk 13 as a storage medium is enclosed in the inner space. The magnetic recording disk or disks 13 are mounted on the driving shaft of a spindle motor 14. The spindle motor 14 drives the magnetic recording disk or disks 13 at a higher revolution speed such as 5,400 rpm, 7,200 rpm, 10,000 rpm, 15,000 rpm, or the like.
A head actuator member or carriage 15 is also enclosed in the inner space. The carriage 15 includes a carriage block 16. The carriage block 16 is supported on a vertical support shaft 17 for relative rotation. Carriage arms 18 are defined in the carriage block 16. The carriage arms 18 are designed to extend in a horizontal direction from the vertical support shaft 17. The carriage block 16 may be made of aluminum, for example. Extrusion molding process may be employed to form the carriage block 16, for example.
A head suspension 19 is attached to the front or tip end of the individual carriage arm 18. The head suspension 19 is designed to extend forward from the carriage arm 18. A gimbal spring, not shown, is connected to the front end of the individual head suspension 19. A flying head slider 21 is fixed on the surface of the gimbal spring. The gimbal spring allows the flying head slider 21 to change its attitude relative to the head suspension 19. An electromagnetic transducer, not shown, is mounted on the flying head slider 21 as described later in detail.
When the magnetic recording disk 13 rotates, the flying head slider 21 is allowed to receive airflow generated along the rotating magnetic recording disk 13. The airflow serves to generate a positive pressure or a lift and a negative pressure on the flying head slider 21. The flying head slider 21 is thus allowed to keep flying above the surface of the magnetic recording disk 13 during the rotation of the magnetic recording disk 13 at a higher stability established by the balance between the urging force of the head suspension 19 and the combination of the lift and the negative pressure.
When the carriage 15 is driven to swing around the vertical support shaft 17 during the flight of the flying head slider 21, the flying head slider 21 is allowed to move along the radial direction of the magnetic recording disk 13. This radial movement allows the electromagnetic transducer on the flying head slider 21 to cross the data zone between the innermost recording track and the outermost recording track. The electromagnetic transducer on the flying head slider 21 can thus be positioned right above a target recording track on the magnetic recording disk 13.
A power source 22 such as a voice coil motor, VCM, is coupled to the carriage block 16. The power source 22 allows the carriage block 16 to swing about the vertical support shaft 17. The swinging movement of the carriage block 16 realizes the swinging movement of the carriage arms 18 and the head suspensions 19.
A front rail 31, a rear rail 32 and a pair of side rails 33, 33 are formed on the bottom surface 26 of the slider body 25. The front rail 31 stands upright from the flat base surface of the bottom surface 26 near the inflow end of the slider body 25. The rear rail 32 stands upright from the flat base surface of the bottom surface 26 near the outflow end of the slider body 25. The side rails 33, 33 stand upright from the flat base surface of the bottom surface 26 near the outflow end of the slider body 25. Air bearing surfaces, ABSs, 34, 35, 36 are respectively defined on the top surfaces of the front, rear and side rails 31, 32, 33. The inflow ends of the air bearing surfaces 34, 35, 36 are connected to the top surfaces of the front, rear and side rails 31, 32, 33 through steps 37, 38, 39, respectively.
The bottom surface 26 of the flying head slider 21 is designed to receive airflow 27 generated along the rotating magnetic recording disk 13. The steps 37, 38, 39 serve to generate a larger positive pressure or lift at the air bearing surfaces 34, 35, 36. Moreover, a larger negative pressure is induced behind the front rail 31. The negative pressure is balanced with the lift so as to stably establish the flying attitude of the flying head slider 21.
The aforementioned electromagnetic transducer, namely a read/write head element 41, is mounted on the slider body 25. The read/write head element 41 is embedded within the head protection layer 29 of the head slider body 25. The read/write head element 41 is designed to expose the read gap and the write gap at the air bearing surface 35 of the rear rail 32. It should be noted that the front end of the read/write head element 41 may be covered with a protection layer, made of diamond-like-carbon (DLC), extending over the air bearing surface 35. The read/write head element 41 will be described later in detail. The flying head slider 21 may take any shape or form other than the aforementioned one.
A larger positive pressure or lift is generated on the air bearing surface 34 as compared with the air bearing surfaces 35, 36 in the flying head slider 21. When the slider body 25 flies above the surface of the magnetic recording disk 13, the slider body 25 can be kept at an inclined attitude defined by a pitch angle a. Here, the term “pitch angle” is used to define an inclined angle in the longitudinal direction of the slider body 25 along the direction of the airflow.
The inductive write head element 42 and the read head element 43 are interposed between an Al2O3 overcoat film 44 and an Al2O3 undercoat film 45. The overcoat film 44 corresponds to the upper half of the aforementioned head protection film 29, while the undercoat film 45 corresponds to the lower half of the head protection film 29.
The read head element 43 includes a magnetoresistive film 46, such as a tunnel-junction film, interposed between a pair of electrically-conductive layers or lower and upper shielding layers 47, 48. The magnetoresistive film 46 is embedded in an insulating layer 49, made of Al2O3, for example, covering over the upper surface of the lower shielding layer 47. The upper shielding layer 48 extends along the upper surface of the insulating layer 49. The lower and upper shielding layers 47, 48 may be made of a magnetic material such as FeN, NiFe, or the like. The interval between the lower and upper shielding layers 47, 48 serves to determine a linear resolution of magnetic recordation on the magnetic recording disk 13 along the recording track.
The inductive write head element 42 includes a first magnetic pole or lower magnetic pole 51 and a second magnetic pole or upper magnetic pole 52. The lower and upper magnetic poles 51, 52 are designed to extend backward from their front ends exposed at the air bearing surface 35. The lower and upper magnetic poles 51, 52 may be made of a magnetic material such as FeN, NiFe, or the like. The lower and upper magnetic poles 51, 52 in combination establish a magnetic core of the inductive write head element 42 as described later.
A magnetic pole end layer 53 is located in a space between the lower and upper magnetic poles 51, 52. The magnetic pole end layer 53 has a front end exposed at the air bearing surface 35. The magnetic pole end layer 53 defines a layer body 53a and a front piece 53b formed on the surface of the layer body 53a. The front piece 53b is opposed to the upper magnetic pole 52. The width of the front piece 53b is set equal to that of the upper magnetic pole 52 in the lateral direction of the recording track. The width of the layer body 53a may be set considerably larger than that of the front piece 53b in the lateral direction of a recording track. The width of the layer body 53a may be set equal to that of a conventional magnetic pole end layer. The magnetic pole end layer 53 may be made of a magnetic material such as FeN, NiFe, or the like. It should be noted that the front piece 53b may be made of a magnetic material having a high saturation flux density (Bs).
A magnetic piece 54 is interposed between the magnetic pole end layer 53 and the lower magnetic pole 51. The magnetic piece 54 connects the magnetic pole end layer 53 to the lower magnetic pole 51 along the air bearing surface 35. The magnetic piece 54 may be made of a magnetic material such as FeN, NiFe, or the like. A non-magnetic material made of Al2O3 or the like, namely an insulating layer 55, covers over the surface of the lower magnetic pole 51 at a position adjacent to the magnetic piece 54. The insulating layer 55 fills a space between the magnetic pole end layer 53 and the lower magnetic pole 51 along the air bearing surface 35. An insulating layer 56 made of Al2O3 or the like covers over the surface of the insulating layer 55 at a position adjacent to the layer body 53a.
A non-magnetic gap layer 57, made of Al2O3 or the like, is interposed between the front piece 53b of the magnetic pole end layer 53 and the upper magnetic pole 52. When a magnetic field is generated in the aftermentioned magnetic coil, magnetic flux runs through the upper magnetic pole 52, the front piece 53b, the layer body 53a, the magnetic piece 54 and the lower magnetic pole 51 in this sequence. Likewise, magnetic flux runs through the lower magnetic pole 51, the magnetic piece 54, the layer body 53a and the front piece 53b and the upper magnetic pole 52 in this sequence. The non-magnetic gap layer 57 serves to leak the magnetic flux between the upper and lower magnetic poles 52, 51 out of the bottom surface 26. The leaked magnetic flux forms a magnetic field for recordation.
Referring also to
An insulating layer 63 is overlaid on the insulating layer 56. The surface of the thin film coil 62 is thus covered with the insulating layer 63. The aforementioned upper magnetic pole 52 is formed on the insulating layer 63. The aforementioned overcoat film 44 covers over the surface of the upper magnetic pole 52. A connecting piece 59 magnetically connects the rear end of the upper magnetic pole 52 to the lower magnetic pole 51 at the central position of the thin film coils 61, 62. The connecting piece 59 is made of a magnetic material such as FeN, NiFe, or the like. The upper and lower magnetic poles 52, 51, the magnetic pole end layer 53, the magnetic piece 54 and the connecting piece 59 in combination establish a magnetic core extending through the central position of the thin film coils 61, 62.
The thin film coil 61 is designed to extend along the surface of an insulating layer 64 made of Al2O3, for example. The insulating layer 64 is overlaid on the lower magnetic pole 51. The thin film coil 62 is designed to extend along the surface of an insulating layer 65 made of Al2O3, for example. The insulating layer 65 is overlaid on the thin film coil 61. It should be noted that the thin film coils 61, 62 are electrically connected to each other. As is apparent from
When magnetic bit data is to be written, a writing current is supplied to the thin film coils 61, 62. A magnetic field is generated at the thin film coils 61, 62 in response to the supply of the writing current. A magnetic flux in this manner runs through the lower and upper magnetic poles 51, 52, the magnetic pole end layer 53 and the magnetic piece 54. The non-magnetic gap layer 57 serves to leak the magnetic flux between the lower and upper magnetic poles 51, 52 out of the bottom surface 26. The leaked magnetic flux forms a magnetic field for recordation. Binary data is in this manner written onto the magnetic recording disk 13.
The insulating layer 55 extends between the lower magnetic pole 51 and the magnetic pole end layer 53 in the read/write head element 41. The insulating layer 55 fills a space between the lower magnetic pole 51 and the magnetic pole end layer 53 at a position adjacent to the magnetic piece 54. The insulating layer 55 contributes to a reduction in the volume of a magnetic body between the lower magnetic pole 51 and the magnetic pole end layer 53 as compared with the case where a magnetic body fills the entire space between the lower magnetic pole 51 and the magnetic pole end layer 53. The volume of a magnetic body is reduced in the inductive write head element 42. The flux path of the magnetic flux can be narrowed. This results in a reduction in the inductance of the thin film coils 61, 62. A reduced inductance enables a reliable high-frequency recordation. Furthermore, as long as the magnetic pole end layer 53 has a width equal to the width of a conventional magnetic pole end layer in the lateral direction of a recording track, the magnetic field for recordation of a conventional magnitude can be maintained based on the magnetic flux running between the upper magnetic pole 52 and the magnetic pole end layer 53.
In addition, the thin film coils 61, 62 generate heat in response to the supply of the writing current. The generated heat causes thermal expansion of the insulating layers 55, 56 as well as the lower and upper magnetic poles 51, 52. Al2O3 as the non-magnetic material for the insulating layers 55, 56 has a coefficient of thermal expansion smaller than that of FeN or NiFe as the material for the lower and upper magnetic poles 51, 52. Since the magnetic piece 54 has a reduced volume at a position between the lower magnetic pole 51 and the magnetic pole end layer 53, the magnetic piece 54 only suffers from a reduced thermal expansion. A reduced thermal expansion leads to suppression of protrusion of the inductive write head element 42 out of the air bearing surface 35. This results in avoidance of variation in the flying height of the flying head slider 21.
Next, a brief description will be made on a method of making the flying head slider 21. A wafer made of Al2O3—TiC or the like is prepared. As shown in
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A magnetic pole end layer 78 is located in a space between the main magnetic pole 76 and the auxiliary magnetic pole 77. The magnetic pole end layer 78 has a front end exposed at the air bearing surface 35. The magnetic pole end layer 78 may be made of a magnetic material such as FeN, NiFe, or the like. The magnetic pole end layer 78 is opposed to the main magnetic pole 76. The width of the magnetic pole end layer 78 may be set considerably larger than that of the main magnetic pole 76 in the lateral direction of a recording track.
Three magnetic pieces 79, 79, 79 are interposed between the magnetic pole end layer 78 and the auxiliary magnetic pole 77, for example. The magnetic pieces 79 may be spaced from one another at a predetermined interval. The magnetic pieces 79 connects the magnetic pole end layer 78 to the auxiliary magnetic pole 77 along the air bearing surface 35. The magnetic pieces 79 may be made of a magnetic material such as FeN, NiFe, or the like. A non-magnetic material such as Al2O3, namely an insulating layer 81 fills a space around the magnetic pieces 79. The insulating layer 81 in this manner fills a space between the magnetic pole end layer 78 and the auxiliary magnetic pole 77 along the air bearing surface 35.
The aforementioned non-magnetic gap layer 57 is interposed between the main magnetic pole 76 and the magnetic pole end layer 78. When a magnetic field is generated at the magnetic coil, A magnetic flux runs through the main magnetic pole 76, the magnetic pole front layer 78, the magnetic pieces 79 and the auxiliary magnetic pole 77, as described later. The non-magnetic gap layer 57 serves to leak the magnetic flux, running from the main magnetic pole 76 to the auxiliary magnetic pole 77, out of the bottom surface 26. The leaked magnetic flux forms a magnetic field for recordation.
Referring also to
When magnetic bit data is to be written, a writing current is supplied to the thin film coil 82. A magnetic field is generated at the thin film coil 82. A magnetic flux in this manner runs through the main magnetic pole 76, the magnetic pole end layer 78, the magnetic pieces 79, the auxiliary magnetic pole 77 and the connecting piece 83. The non-magnetic gap layer 57 serves to leak the magnetic flux out of the bottom surface 26. The leaked magnetic flux forms a magnetic field for recordation. Binary data is in this manner written onto the magnetic recording disk 13.
The insulating layer 81 fills a space between the magnetic pole end layer 78 and the auxiliary magnetic pole 77 along the air bearing surface 35 in the read/write head element 41a. The insulating layer 81 contributes to a reduction in the volume of a magnetic body between the auxiliary magnetic pole 77 and the magnetic pole end layer 78. The volume of a magnetic body is reduced in the single pole head 75. The flux path of the magnetic flux can be narrowed. This results in a reduction in the inductance of the thin film coil 82. A reduced inductance enables a reliable high-frequency recordation. Furthermore, as long as the magnetic pole end layer 78 has a width equal to the width of a conventional magnetic pole end layer in the lateral direction of a recording track, the magnetic field for recordation of a conventional magnitude can be maintained based on the magnetic flux running between the main magnetic pole 76 and the auxiliary magnetic pole 77.
In addition, the thin film coil 82 generates heat in response to the supply of the writing current. The generated heat causes thermal expansion of the non-magnetic gap layer 57, the insulating layer 81, the main magnetic pole 76 and the auxiliary magnetic pole 77. Al2O3 as the non-magnetic material for the non-magnetic gap layer 57 and the insulating layer 81 has a coefficient of thermal expansion smaller than that of FeN or NiFe as the material for the main magnetic pole 76 and the auxiliary magnetic pole 77. The thermal expansion is suppressed. A reduced thermal expansion leads to suppression of protrusion of the single pole head 75 out of the air bearing surface 35. This results in avoidance of variation in the flying height of the flying head slider 21.
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Referring also to
Number | Date | Country | Kind |
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2006-211371 | Aug 2006 | JP | national |