JP3475868B2 - Magnetoresistive thin-film magnetic head - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic field applied to a device for performing high-density recording / reproduction on a magnetic recording medium such as a magnetic disk device (HDD device). The present invention relates to a resistive thin film magnetic head. [0002] In recent years, magnetic disk devices (HDD devices)
In recording on magnetic recording media such as, there is an increasing need to increase the processing speed and increase the recording capacity, and efforts to increase the recording density are being strengthened. Therefore, the distance between adjacent recording tracks has been further narrowed. Hereinafter, a conventional thin film magnetic head will be described with reference to the drawings. FIGS. 7 and 8 are views showing a conventional thin film magnetic head. FIG. 7 is a schematic perspective view, and FIG. 8 is a front schematic view of the thin film magnetic head. For example, many thin-film magnetic heads used for recording and reproducing signals on a magnetic recording medium in a magnetic disk drive are so-called MR (GMR) inductive composite heads as shown in FIG. In FIG. 7, Al ₂ O ₃ and AlN are formed on a lower shield layer 71 formed of a soft magnetic material such as a permalloy, Co-based amorphous magnetic film or Fe-based alloy magnetic film.
Alternatively, a lower gap insulating layer 72 is formed using a nonmagnetic insulating material such as SiO _2, and a magnetoresistive effect element (MR element or GMR element; hereinafter, referred to as a GMR element) 73 is formed on the lower gap insulating layer 72. Then, a longitudinal bias layer 74 is formed of a material such as a CoPt alloy on both left and right ends of the GMR element 73. Upper surface of vertical bias layer 74 and GMR element 7
The electrode lead layer 75 is formed using a material such as Cu, Cr, or Ta so as to cover a part of the upper surface of the electrode lead layer 75.
Here, the electrode lead layer 75 does not extend over a part of the upper surface of the GMR element 73, but comes into contact with a ridge line which is an intersection between the upper surface of the GMR element 73 and both side surfaces thereof, and only the upper surface of the vertical bias layer 74. It may be made to form a film. Next, an upper gap insulating layer 76 is formed on the exposed portions of the electrode lead layer 75 and the GMR element 73 using the same nonmagnetic insulating material as the lower gap insulating layer 72. Further, an upper shield layer 77 is formed on the upper gap insulating layer 76 using the same soft magnetic material as that of the lower shield layer 71, thereby forming a magnetoresistive thin film magnetic head 78 for reproduction. Next, a recording gap layer 701 is formed on the upper surface of the upper shield layer 77 by using the same non-magnetic insulating material as the lower gap insulating layer 72, and the recording gap layer 701 is further formed.
The upper magnetic pole 702 facing the upper shield layer 77 through the gap and being in contact with the upper shield layer 77 at other portions is formed using a soft magnetic material. Between the portion where the upper magnetic pole 77 and the upper magnetic pole 702 face each other and the portion where the upper magnetic pole 702 is in contact with the upper shield layer 77, the upper shield layer 77 and the upper magnetic pole 7
A winding coil 703 that is insulated from the drive coil 02 via an insulating material (not shown) is provided to form an inductive thin-film magnetic head 700 for recording. Here, the upper shield layer 77 has a function of both the shield function of the magnetoresistive thin film magnetic head section 78 for reproduction and the lower magnetic pole function of the inductive thin film magnetic head section 700 for recording. FIG. 8 is a schematic front view showing the vicinity of a magnetoresistive element in a reproducing head portion of a thin film magnetic head. As shown in FIG. 8, FeMn is formed on a lower gap insulating layer 72 formed on the upper surface of a lower shield layer 71. -Ferromagnetic layer 801 which is a material such as a PtMn-based alloy film, a pinned magnetic layer 802 which is made of a FeNi-based alloy film, a permalloy, Co, FeCo alloy film or the like, and a non-magnetic conductive material which is a material such as Cu. Layer 8
03, free magnetic layer 80 made of the same material as the pinned magnetic layer
4 and a cap layer 805 made of Ta or the like are sequentially stacked and formed by etching such as ion milling so that both right and left ends have inclined surfaces to form the GMR element 73. A pair of left and right vertical bias layers 74 are formed in contact with both left and right end surfaces of the GMR element, and a pair of left and right electrode lead layers 75 are formed thereon. Furthermore,
An upper gap insulating layer 76 is formed thereon, and an upper shield layer 77 is further formed thereon. Further, a recording gap layer 701 is formed thereon, and an upper magnetic pole 702 is formed thereon. When a recording current is supplied to the winding coil 703, a recording magnetic field is generated in the upper magnetic pole 702 and the upper shield layer 77 of the recording induction type thin-film magnetic head 700, and the recording magnetic field is opposed to each other via the recording gap layer 701. Upper magnetic pole 7
02 and the upper shield layer 77 generate a magnetic flux leakage,
A recording signal is recorded on a magnetic recording medium. The magnetic field of the signal recorded on the magnetic recording medium on which the signal is recorded is reproduced by the reproducing magnetoresistive thin film magnetic head section 78, and the reproduced signal corresponding to the resistance change by the GMR element 73 is output from the electrode lead layer 75. Detect from terminal. Conventionally, as shown in FIG. 8, the reproducing head track width 8 of the reproducing magnetoresistive thin film magnetic head is smaller than the recording head track width 81 of the recording inductive thin film magnetic head.
2 is slightly reduced so that off-track during reproduction can be dealt with. On the other hand, a servo function is added so as to reproduce only the recording magnetic field of the recording signal of the recording track to be reproduced, and the off-track is reduced while reproducing while correcting the trajectory of the GMR element with respect to the recording track. I have. However, in the above-mentioned conventional thin film magnetic head, in order to increase the recording density, the recording track width is reduced in order to increase the track density, and at the same time, the adjacent recording is performed. The distance between tracks also needs to be narrow, and if the distance between adjacent recording tracks becomes smaller, the magnetoresistive thin-film magnetic head for reproduction reproduces the recording magnetic field of the recording signal of the adjacent recording track as noise. There was a problem of becoming. In order to reduce the track width of the reproducing head, the width of the GMR element of the magnetoresistive thin-film magnetic head must be reduced, and a pair of left and right vertical biases formed in contact with the left and right ends of the GMR element. The spacing between the layers becomes very small and G
There is a problem that a strong magnetic field of the vertical bias layer is supplied to the MR element, and the reproduction sensitivity when reproducing a recording signal is reduced. The present invention solves the above-mentioned problems and suppresses crosstalk from adjacent recording tracks by devising the positional relationship between the GMR element and the vertical bias layer or modifying the shape of the GMR element. It is an object of the present invention to provide a reproducing magnetoresistive head capable of reproducing. In order to achieve this object, a magnetoresistive head according to the present invention is provided with a free magnetic layer formed on a lower gap insulating layer formed on a lower shield layer. Layer, a non-magnetic conductive layer, a pinned magnetic layer, and an antiferromagnetic layer are sequentially formed and formed on the magnetoresistive element, and a first plane of the antiferromagnetic layer having a predetermined read head track width on its upper surface; A second plane in which either the fixed magnetic layer or the nonmagnetic conductive layer has a step with respect to the first plane, and has a thickness substantially equal to the thickness from the lower gap insulating layer to the second plane; A vertical bias layer is formed so as to have a thickness so as to be in contact with both left and right end surfaces of the magnetoresistive element. With this configuration, only the portion below the first plane contributes to the electromagnetic conversion, and the first track of the GMR element corresponds to the narrow track width accompanying the high recording density.
The width of the read head track formed by the plane of
Even if the second plane extends over an adjacent track of the narrow recording track, the recording signal magnetic field of the adjacent track is not electromagnetically converted into noise, crosstalk can be reduced, and high recording can be achieved. Even if the track width of the read head formed by the first plane of the GMR element is reduced in response to the narrow track width accompanying the increase in density, the distance between the pair of vertical bias layers on the left and right sides of the GMR element is increased. Therefore, it is possible to obtain an effect that the reproduction sensitivity when reproducing the recording signal is not reduced. The invention according to the first aspect of the present invention has a magnetoresistive element between a lower shield layer and an upper shield layer via an insulating material. Then, in a magnetoresistive thin film magnetic head comprising a vertical bias layer provided in contact with both left and right ends of the magnetoresistive element and an electrode lead layer for flowing a signal current, a film is formed on the lower shield layer. A magnetoresistive element in which a free magnetic layer, a non-magnetic conductive layer, a fixed magnetic layer, and an antiferromagnetic layer are sequentially formed on the formed lower gap insulating layer has a predetermined reproducing head track width formed on the upper surface thereof. A lower plane having a first plane of the antiferromagnetic layer having the first plane, and a second plane in which either the fixed magnetic layer or the non-magnetic conductive layer has a step with respect to the first plane. Thickness from to the second plane A vertical bias layer is formed in contact with the left and right end faces of the magnetoresistive element so as to have substantially the same thickness, and only a portion below the first plane contributes to electromagnetic conversion. As a result, even if the width of the reproduction head track formed by the first plane of the GMR element is reduced and the second plane is applied to the adjacent track of the narrow recording track, the recording signal magnetic field of the adjacent track is electromagnetically converted. Also, even if the read head track width formed by the first plane of the GMR element is reduced, the distance between the pair of vertical bias layers on the left and right sides of the GMR element can be increased. This has the effect of not lowering the reproduction sensitivity when reproducing the recorded signal. Hereinafter, embodiments of the present invention will be described with reference to the drawings. (First Embodiment) FIG. 1 is a schematic front view showing the vicinity of a magnetoresistive element according to a first embodiment of the present invention. As shown in FIG. 1, Al ₂ O ₃ on the bottom shield layer 11 which is formed of a soft magnetic material, AlN or S
A lower gap insulating layer 12 is formed using a non-magnetic insulating material such as iO ₂ , and a FeNi-based alloy film,
Free magnetic layer 13 made of permalloy, Co, FeCo alloy film or the like, nonmagnetic conductive layer 14 made of Cu or the like,
The pinned magnetic layer 15 is formed using the same material as the free magnetic layer 13.
An antiferromagnetic layer 16, which is a material such as a FeMn-based alloy film or a PtMn-based alloy film, is formed by sequentially laminating thin films to form a magnetoresistive element 1 (GMR element; hereinafter referred to as a GMR element). It is formed. The upper surface of the antiferromagnetic layer 16 which is the uppermost layer of the GMR element 1 is formed with a predetermined read head track width, and forms a first plane 2. On the left and right sides of the first plane 2 and on the second plane 3 having a step from the first plane 2, the surface of the fixed magnetic layer 15 constituting the GMR element 1 is exposed. Has a shape having a convex portion on the top. The left and right end surfaces 4 of the GMR element 1 are formed so as to have inclined surfaces by an etching method such as ion milling. The GMR element 1 is in contact with the left and right end surfaces 4, and extends from the upper surface of the lower gap insulating layer 12. A pair of left and right vertical bias layers 5 are formed on the lower gap insulating layer 12 so as to have a thickness substantially equal to the thickness up to the plane 3 of FIG. Further, a pair of left and right electrode lead layers 6 are formed on the vertical bias layer 5 so as not to cover the first plane 2 of the GMR element 1. The electrode lead layer 6 may be formed only on the vertical bias layer 5 as shown in FIG. 2A or FIG.
(C) or as shown in FIG.
, The upper surface of the second plane 3 of the GMR element 1 and the GMR
The film may be formed so as to cover a part or all of the left and right side surfaces connecting the first plane 2 and the second plane 3 of the element 1. Further, an upper gap insulating layer (not shown) and an upper shield layer (not shown) are formed thereon to form a reproducing magnetoresistive thin film magnetic head. As shown in FIG. 3A, the first plane 2 of the GMR element 1, the first plane 2 and the second plane
A cap layer 31 using Ta or the like as a material may be formed on the left and right side surfaces and the second plane 3 that respectively connect to the plane 3. Also, as shown in FIG.
It goes without saying that the GMR element 1 may be formed after the intermediate intermediate layer 32 is formed on the lower gap insulating layer 12 using a material such as Ta. As described above, according to the first embodiment, at least the uppermost antiferromagnetic layer of the GMR element, which is on the second plane, is cut off.
Since the fixed magnetic layer is not fixed by the antiferromagnetic layer in a portion corresponding to a portion below the plane of, the magnetoresistance effect is lost,
Only the portion below the above-mentioned first plane contributes to the electromagnetic conversion, and the read head track formed by the first plane of the GMR element corresponds to the narrow track width accompanying the high recording density. Even if the width becomes small and the above-mentioned second plane is applied to a track adjacent to the narrow recording track, the recording signal magnetic field of the adjacent track is not electromagnetically converted into noise and crosstalk is reduced. In response to the narrow track width accompanying high recording density, G
Even if the track width of the reproducing head formed by the first plane of the MR element is reduced, the distance between the pair of vertical bias layers on the left and right sides of the GMR element can be increased, and the reproducing sensitivity when reproducing a recording signal can be improved. It does not lower. In the above-described embodiment, the fixed magnetic layer 15 is exposed on the second plane 3. However, the magnetoresistance effect is lost below the second plane 3. Needless to say, as shown in FIG. 3C, the surface of the nonmagnetic conductive layer 14 constituting the GMR element 1 may be exposed as the second plane 3. (Embodiment 2) FIG. 4 is a schematic front view of a reproducing magnetoresistive thin-film magnetic head according to Embodiment 2 of the present invention. In FIG. 4, Al ₂ O ₃ , Al ₂ O ₃ , and Al are formed on a lower shield layer 41 formed of a soft magnetic material such as a permalloy, Co-based amorphous magnetic film, or Fe-based alloy magnetic film.
The lower gap insulating layer 42 is formed using a non-magnetic insulating material such as N or SiO ₂ . In addition, Fe
Antiferromagnetic layer 401 made of a material such as a Mn-based alloy film or a PtMn-based alloy film, a FeNi-based alloy film, Permalloy, Co, F
A fixed magnetic layer 402 made of eCo alloy film or the like, a nonmagnetic conductive layer 403 made of Cu or the like, a free magnetic layer 404 made of the same material as the fixed magnetic layer 402, and a cap layer 405 made of Ta or the like are formed. The GMR element 43 is formed by sequentially laminating each of the thin films and shaving off the left and right side edges to have inclined surfaces by an etching process such as ion milling.
Are formed. Although the antiferromagnetic layer 401 is formed on the lower gap insulating layer 42, in order to stabilize the characteristics of the antiferromagnetic layer 401, a metal film such as Ta is formed on the lower gap insulating layer 42 via a metal film such as Ta. The antiferromagnetic layer 401 may be formed. Next, a soft magnetic material such as a Co-based amorphous magnetic film or an Fe-based alloy magnetic film is in contact with the inclined left and right end surfaces of the GMR element 43 and has a thickness substantially equal to the laminated film thickness of the GMR element 43. A soft magnetic intermediate layer 44 of a material or the like having no magnetoresistance effect is formed and formed so that the soft magnetic intermediate layer 44 is in contact with the left and right end surfaces opposite to the side surfaces in contact with the MR element 43. A vertical bias layer 45 made of a hard magnetic film is formed. Vertical bias layer 4
An electrode lead layer 46 made of Ta, W, or the like is formed and formed so as to be in contact with the ridge line which is the intersection of the upper surface of the GMR element 43 and both sides of the GMR element 43 and the soft magnetic intermediate layer 44. Next, an upper gap insulating layer 47 is formed on the exposed portions of the electrode lead layer 46 and the MR element 43 using the same non-magnetic insulating material as the lower gap insulating layer 42. An upper shield layer 48 is formed on the 47 by using the same soft magnetic material as the lower shield layer 41 to form a magnetoresistive thin-film magnetic head 49 for reproduction. The reproducing head track width of the magnetoresistive thin-film magnetic head section 49 is a gap 40 on the GMR element 43, and the soft magnetic intermediate layer 44 has no magnetoresistive effect. This is determined from the viewpoint of system design such as servo, but in the case of the present embodiment, the read head track width of the mechanical dimensions and the magnetic read head track width are substantially the same. FIG. 5 is a schematic front view showing the vicinity of a GMR element according to another example of the second embodiment. As described above, the GMR element 52 is formed on the lower gap insulating layer 51 formed on the lower shield layer (not shown). A pair of left and right soft magnetic intermediate layers 53 made of a soft magnetic material and having substantially the same thickness as the laminated film thickness of the GMR element 52 are formed in contact with both left and right end surfaces of the GMR element 52. Further, GMR is provided on the soft magnetic intermediate layer 53.
A FeMn-based alloy film, N
A pair of left and right vertical bias layers 54 made of an antiferromagnetic film such as an iMn-based alloy film or a hard magnetic film such as a PtMn-based alloy film is formed, and a ridgeline where the upper surface and both side surfaces of the GMR element 52 intersect is formed thereon. The electrode lead layer 55 is formed by applying a photoresist so as to be in contact with the substrate. Note that, as shown in FIG.
May be applied to the upper surface of a part of the GMR element 43. At this time, the width 61 of the exposed portion of the GMR element becomes the reproducing head track width. The longitudinal bias layer 45 having the effect of reducing Barkhausen noise of the GMR element 43 is opposed to the GMR element 43 via the soft magnetic intermediate layer 44, and is directly connected to the GM.
Although not in contact with the R element 43, the interposed soft magnetic intermediate layer 44 is formed of a soft magnetic material, so that the longitudinal bias layer 45 and the GMR element 43 are magnetically coupled, The vertical bias magnetic field generated by the vertical bias layer 45 is effectively applied to the GMR element 43, and Barkhausen noise is suppressed. Further, when the GMR element is in direct contact with the vertical bias layer as in the above-described conventional example, the GMR element near the surface where the GMR element is in contact receives a large magnetic field of the vertical bias layer, which hinders the magnetization rotation of the free magnetic layer. Accordingly, the amount of change in resistance of the GMR element with respect to the change in the magnetic field is reduced. When separated from the surface in contact with the vertical bias layer, the direction of magnetization of the GMR element in response to a change in the external magnetic field rotates, causing a change in resistance, but in a region where rotation of the magnetization is inhibited (hereinafter, this region is referred to as an unstable region). Area), and continuously changes from an unhindered area (hereinafter, referred to as a stable area), and also varies depending on the state of the contact surface between the vertical bias layer and the GMR element and the characteristic unstable area of the vertical bias layer. In addition, the distance between the unstable region of magnetization rotation and the stable region varies, which causes the off-track characteristic to deteriorate. In the above-described embodiment, since the vertical bias layer and the soft magnetic intermediate layer are in contact with each other, there is no unstable region, and the off-track characteristics can be improved. As described above, according to the present invention, the lower shield layer
Free magnetic layer on the lower gap insulating layer
Layer, nonmagnetic conductive layer, pinned magnetic layer and antiferromagnetic layer
The magnetoresistive element formed as a film is
First plane of antiferromagnetic layer with raw head track width
A fixed magnetic layer having a step relative to the first plane or
A second plane on which any surface of the nonmagnetic conductive layer is exposed;
From the lower gap insulating layer to the second plane
The magnetoresistive effect so as to have a thickness substantially equal to
Vertical bias layers formed on the left and right sides of the device
As a result, only the portion below the first plane is subjected to electromagnetic conversion.
Narrow track due to higher recording density
The first plane of the magnetoresistive element is configured to correspond to the width
The read head track width becomes smaller, and the second plane becomes
Even if it hits a track adjacent to a narrow recording track,
Electromagnetically converts the recording signal magnetic field of the adjacent track into noise
It is possible to reduce crosstalk
In response to narrower track widths associated with higher recording densities.
Thus, the reproducing head formed by the first plane of the magnetoresistive element is
Even if the track width is reduced, the magnetoresistive effect element
Increase the distance between a pair of left and right vertical bias layers
Lowers the playback sensitivity when playing back recorded signals.
The effect that there is not can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic front view of a reproducing magnetoresistive thin-film magnetic head according to a first embodiment of the present invention. FIG. 2 shows another example of the first embodiment of the present invention. GMR
FIG. 3 is a schematic front view of a vicinity of a GMR element showing another example of the first embodiment of the present invention. FIG. 4 is a schematic front view of a vicinity of a GMR element showing a second embodiment of the present invention. FIG. 5 is a GMR showing another example of the second embodiment of the present invention.
FIG. 6 is a schematic front view of a GMR element showing another example of the second embodiment of the present invention. FIG. 7 is a perspective view showing a conventional thin film magnetic head. FIG. 8 is a conventional thin film magnetic head. 1, 43, 52, 73 Magnetoresistance effect element (GMR element) 2 First plane 3 Second plane 4 End face 5, 45 54, 74 Vertical bias layers 6, 46, 55, 75 Electrode lead layers 11, 41, 71 Lower shield layers 12, 42, 51, 72 Lower gap insulating layers 13, 404, 804 Free magnetic layers 14, 403, 803 Nonmagnetic Conductive layers 15, 402, 802 Fixed magnetic layers 16, 401, 801 Antiferromagnetic layers 31, 405, 805 Cap layers 32 Intervening layers 40 Intervals 44, 53 Soft magnetic intermediate layers 47, 76 Upper gap gap Edge layers 48, 77 Upper shield layers 49, 78 Magnetoresistive thin-film magnetic head 61 Width 81, 82 Track width 700 Inductive thin-film magnetic head 701 Recording gap layer 702 Upper magnetic pole 703 Winding coil

Claims (1)

(1) A magneto-resistive element is provided between a lower shield layer and an upper shield layer with an insulating material interposed therebetween. In a magnetoresistive thin-film magnetic head comprising a vertical bias layer provided by a magnetic head and an electrode lead layer for flowing a signal current, a free magnetic layer is formed on a lower gap insulating layer formed on a lower shield layer. A magnetoresistive element in which a nonmagnetic conductive layer, a pinned magnetic layer, and an antiferromagnetic layer are sequentially formed and formed on a first plane of an antiferromagnetic layer having a predetermined read head track width on its upper surface; A second plane in which either the fixed magnetic layer or the non-magnetic conductive layer has a step with respect to the first plane, and a thickness from the lower gap insulating layer to the second plane. So that they have approximately equal thickness
A thin film magnetic head of the magnetoresistive effect type, wherein a longitudinal bias layer is formed in contact with both left and right end faces of the magnetoresistive element.