JPH07153045A - Magnetic disc apparatus - Google Patents

Abstract

PURPOSE:To facilitate a high speed tracking by a method wherein the sensitivity distribution of a magnetic reluctance effect reproducing head is shifted in a track width direction by an external regulation signal. CONSTITUTION:A magnetism-sensing current is applied to a magnetic reluctance effect film (MR film) through an electrode 13 to detect a magnetic information by the resistance change of the magnetism-sensing part caused by a leakage flux from a magnetic recording medium. In order to obtain linear response characteristics, a horizontal bias magnetic field is applied to the magnetism- sensing part 11 of the MR film by the magnetic field of a power supply or by the leakage magnetic field from a magnetic unit placed near the MR film. At that time, a reproducing sensitivity distribution 14 has its peak at a position shifted in a track width direction from the geometrical center 16 of the magnetism-sensing part. Therefore, the sensitivity distribution is shifted to the right as a whole. The larger the magnetism-sensing current, the larger the shift 17 of the sensitivity peak from the geometrical center 16. This shift of the sensitivity distribution peak position is utilized for the alignment between recording/reproducing tracks and for a narrow tracking.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk device for recording and reproducing information signals on a magnetic recording medium, and more particularly to a magnetoresistive effect for detecting a magnetic field by a resistance change of a magnetoresistive effect film (MR film). The present invention relates to a magnetic disk device using a reproducing head.

[0002]

2. Description of the Related Art FIG. 17 is a schematic diagram showing the components of a magnetic disk drive head positioning system. The magnetic disk 171 is rotated at a predetermined rotation speed by a disk spindle 170 directly connected to a spindle motor, while the magnetic head 172 is rotated in a direction of an arrow by a voice coil motor (VCM) 173, whereby the magnetic disk 17 is rotated.
The magnetic head 172 accesses the magnetic information recorded on the recording medium 1.

In the reproducing head, if the center of the reproducing sensitivity distribution does not coincide with the center of the recorded track, the reproduction signal output decreases and the crosstalk from the adjacent track increases. In a conventional magnetoresistive reproducing head, tracking is performed exclusively by physically moving the position of the entire head by a spindle motor or an actuator.

[0004]

In the conventional tracking method in which the position of the entire head is physically moved, the response characteristic in the high frequency band is limited by the inertial force of the head and the rigidity of the support system. That is, of the mechanical disturbance and electrical noise that influence the control characteristics when the feedback control system is configured, the mechanical disturbance is about several kHz at most in the case of the magnetic disk device. However, the track pitch is 2 μm
In order to realize the following high recording densities, higher speed and more accurate track following characteristics are required. However, the vibration in this band is largely due to the natural frequency of the magnetic disk device structure, and simply driving the conventional actuator at high speed only accelerates the vibration.

A first object of the present invention is to provide a tracking means which can respond at high speed without being affected by the natural vibration of the magnetic disk device. Further, in the recording / reproducing separated type head, the central axis of the recording head and the sensitivity center of the reproducing head do not completely coincide with each other, and a deviation occurs due to variations in the manufacturing process. This misalignment appears as a misalignment between the recording track and the reproducing track, and causes a decrease in reproduction output and an increase in noise. In particular, when the track width is small, it is necessary to provide some means for correcting this deviation for each head. A second object of the present invention is to provide a novel means for correcting the position shift of the sensitivity center of the magnetoresistive effect reproducing head.

[0006]

In the present invention, the second problem is solved by shifting the sensitivity distribution of the magnetoresistive effect reproducing head in the track width direction by an adjustment signal from the outside. That is, the magnetic disk device of the present invention comprises a magnetic recording head, a magnetoresistive effect reproducing head, and reproducing head sensitivity distribution adjusting means for changing the sensitivity distribution in the track width direction of the magnetoresistive effect reproducing head,
The reproducing head sensitivity distribution adjusting means corrects the positional deviation between the magnetic recording head and the magnetoresistive effect reproducing head.

In the present invention, the first problem is solved by shifting the sensitivity distribution of the magnetoresistive effect reproducing head in the track width direction by an adjustment signal from the outside to perform tracking servo. That is, the magnetic disk device of the present invention comprises a magnetoresistive effect reproducing head,
A reproducing head sensitivity distribution for changing the sensitivity distribution in the track width direction of the magnetoresistive effect reproducing head based on the tracking control signal from the tracking control signal generating means. It is characterized by including adjusting means.

The reproducing head sensitivity distribution adjusting means is a means for adjusting a magneto-sensitive current flowing through the MR head, a means for adjusting a current flowing through an adjusting conductor which is disposed near the MR film and electrically insulated from the MR film. It comprises means for adjusting the current distribution on the MR film having the above electrode terminals, means for adjusting the ratio of combining signals from a plurality of MR films having different sensitivity distributions, and the like.

The tracking servo by shifting the sensitivity distribution can be applied to a magnetic recording device by forming a multi-stage servo system in combination with a conventional servo system using a voice coil or the like. FIG. 18 shows a two-stage servo system as an example of such a multi-stage servo system. The tracking shift signal (ry) is obtained from the fine system 181 and co.
It is input to the arse (coarse movement) system 182, and each corrects the head position. The fine system has a high frequency band but has a narrow movable range. On the other hand, the coarse system has a low frequency band but a wide movable range. Where fine
To prevent the system from moving toward the end of its range of motion, fi
The ne system output is added to the coarse system input. Therefore, by utilizing the sensitivity distribution moving mechanism of the MR head of the present invention as a fine system and moving the head position using a conventional voice coil motor (VCM) as a coarse system, a head positioning servo having a wide band is used. The system is built.

[0010]

FIG. 1 shows the structure of the magnetoresistive reproducing head and the sensitivity distribution in the track width direction. As shown in FIG. 1A, in the magnetoresistive effect reproducing head, a magnetosensitive current Is is caused to flow through a magnetoresistive effect film (MR film) made of a magnetic material via an electrode 13 to leak a magnetic field from a magnetic recording medium. Magnetic information is detected by the change in resistance of the magnetically sensitive portion due to.

In general, in order to obtain a linear response characteristic, the magnetic sensitive section 11 of the MR film is used by applying a lateral bias magnetic field by a magnetic field due to a current or a leakage magnetic field from a magnetic material placed in proximity. . At that time, the reproduction sensitivity distribution 14 is
As shown in FIG. 1B, the geometric center 16 of the magnetic sensing part
It is known to have a peak at a position deviated in the track width direction from the above (for example, IEEE Transaction on Magnet
ics, 27, p. 4701). This is, as noted in the figure,
This is because the direction of the magnetization 12 of the magnetically sensitive portion is inclined. That is, the magnetization rotation on the MR film is highly sensitive to the magnetic field from the direction in which the magnetization vector is viewed from the side, but is insensitive to the magnetic field from the direction parallel to the magnetization vector. Therefore, in the figure, the right side portion in the track width direction has a higher sensitivity than the left side portion, and the sensitivity distribution shifts to the right as a whole. When the lateral bias magnetic field is increased to increase the magnetization inclination angle (bias angle), the shift amount 17 of the sensitivity center also increases. In the case of the shunt bias type head, the bias angle becomes larger as the value of the magnetosensitive current is increased, and the deviation 17 of the sensitivity peak position from the geometrical center 16 becomes larger accordingly. On the contrary, when the magnetosensitive current is reduced, the peak position shift becomes smaller, and as a result, the shifted sensitivity distribution 15 can be obtained.

In the present invention, the peak position shift 17 of the sensitivity distribution is utilized for alignment between recording / reproducing tracks and fine tracking. Tracking servo of the magnetic head is realized by detecting a track deviation, and sending a tracking control signal to the head system in accordance with the deviation to correct the head position.

The simplest configuration of the present invention is a method of increasing or decreasing the magnetosensitive current Is itself flowing through the MR head in accordance with the tracking control signal. As shown in FIG. 2, when the current value is increased, the deviation of the sensitivity center position from the geometrical center 16 of the head becomes larger. As a result, the position of the sensitivity center can be swung in the track width direction. However, considering that the magnitude itself of the output changes when the magnetically sensitive current is changed, the range 24 of the current value that can be used in this method is limited to the range in which the output can be sufficiently secured.
It is also impossible to swing positively and negatively over the current value of zero, and as a result, the width 25 of swinging the sensitivity center is limited.

Instead of changing the magnetically sensitive current itself, as shown in FIG. 4, a conductor (adjustment conductor) 22 is provided in the vicinity of the MR film 21, but electrically insulated, and a current is passed through the conductor 22. It is also possible to adjust the direction of the magnetization of the MR film 21 by changing the value of, and shift the position of the sensitivity center and perform tracking with this. In this case, since the magnetosensitive current Is does not need to be changed, the current Ic having an arbitrary value can be passed through the adjusting conductor. At this time, the distribution of the applied magnetic field on the MR film 21 can be variously changed by changing the shape of the adjusting conductor 22 as shown in FIG. 4B.

As another method for changing the sensitivity distribution, as shown in FIG. 8, three or more electrodes 82 are provided on the MR film 81 to change the current distribution on the MR film. As a component of the magnetosensitive current, the shunt ratio is continuously changed between the component a flowing from the upper left to the lower right in FIG. 8 and the component b flowing from the lower left to the upper right. At this time, in the case of only the a-component current, the current distribution on the medium facing surface has a high current density in the right part of FIG. On the contrary, in the case of only the b component current,
The sensitivity distribution increases on the left side of the figure. As a result, FIG.
The sensitivity distribution as shown in (ii) is obtained. By continuously changing the diversion ratio between the current components a and b,
Tracking adjustment is possible by shifting the sensitivity center.

Yet another method of adjusting the sensitivity distribution of the MR head is to use a plurality of MR films having different sensitivity distributions. As a head of this type, there is a head in which two layers of MR films 101A and 101B are laminated as shown in FIG. 10 and biases are applied to each other by an electric current flowing therethrough (IEEE Transaction on Magnetics, 27).
Vol. 4693). In such a structure, the sensitivity distributions of both MR films are symmetrical with respect to the geometric center of the head, and the positions of the sensitivity centers differ from each other by several μm. In the conventional method, as shown in FIG. 11, since the reproduction signal is obtained by a simple difference between the outputs of the two layers of MR films, the position of the sensitivity center is fixed at the position of the geometric center of the head. On the other hand, when the reproduction signal 121 is a weighted average of this reproduction signal as shown in FIG. 12, the sensitivity distribution is continuously variable. By controlling the weighting ratio w by the tracking control signal, fine tracking becomes possible as shown in FIG. This method is characterized in that the movable range can be easily increased to several microns. In addition, a similar method is applied to IEEE Trans.Magn.24, p261.
It is also possible to apply it to the vertical magnetoresistive head (FIG. 14) in which an electric current is passed in the head depth direction disclosed in 2 (1988).

[0017]

【Example】

[Embodiment 1] FIG. 1A shows the structure of a magnetoresistive head used in Embodiment 1. In this embodiment, the magnetosensitive current Is itself flowing through the MR head is increased or decreased according to the tracking control signal. As shown in FIG. 2, when the current value Is is increased, the deviation of the sensitivity center position 18 from the geometrical center 16 of the pattern becomes larger. This allows
It is possible to swing the position of the sensitivity center in the track width direction.

At this time, the tracking control circuit 27 as shown in FIG. 3 is provided in addition to the conventional MR head drive circuit, and the adjusting current Is' based on the tracking control signal 28 is used as the magnetic sensitive current Iso from the constant current power supply 26. The added value is added to the MR magnetic sensing section 11. However, considering that the magnitude of the output itself changes when the magnetically sensitive current is changed, the range 24 of the current value that can be used by this method is limited to the range in which the output can be sufficiently obtained, and the positive and negative values are spread across the zero current value. It is impossible to shake. That is, the current in the broken line portion in FIG. 2 cannot be used. The shiftable width 25 of the sensitivity center position is estimated to be about 10 to 20% of the depth h _MR of the MR film, so h _MR = 3
In the case of μm, it is about 0.3 to 0.6 μm.

[Embodiment 2] FIG. 4 shows the structure of a magnetoresistive head used in Embodiment 2. In this embodiment, a conductor (adjustment conductor) 22 is provided close to the MR film 21, but electrically insulated from the MR film 21, and the direction of magnetization of the MR film 21 is adjusted by changing the current Ic flowing through the conductor 22. , The position of the sensitivity center is shifted, and tracking is performed using this. In the present embodiment, since the magnetosensitive current Is does not have to be changed, it is possible to pass a current having an arbitrary value through the adjusting conductor 22 without changing the head output so much. The relationship between the sensitivity center position 18 and the current Ic of the adjusting conductor is as shown in FIG.

The drive circuit in this case is as shown in FIG. That is, in addition to the normal constant-current power supply 61 that supplies the magnetosensitive current Is to the MR film 21, an amplifier 62 that generates an adjustment current Ic according to the tracking control signal 63 is provided, and this Ic is supplied to the adjustment conductor 22. . In the case of the present embodiment, the shape of the adjusting conductor 22 is changed to the MR film 21 as shown in FIG.
In the case where the overlapping portion has a constant width, the magnetization center position is changed by uniformly rotating the magnetization direction of the MR film, as in the previous embodiment.

On the other hand, if the width of the adjusting conductor 22 is changed in the track width direction as shown in FIG. 4B, the sensitivity center 18 can be moved more positively. That is, the bias magnetic field is large when the width of the adjusting conductor 22 is narrow, and is small when the width of the adjusting conductor 22 is large. Accordingly, the sensitivity distribution can be shifted as shown in FIG. That is, the sensitivity of the MR film has a peak at the optimum bias magnetic field. When the value of the current flowing to the adjusting conductor is changed to I ₁ , I ₂ , and I ₃ (I ₁ <I ₂ <I ₃ ), the position in the MR film 21 in the track width direction at which the optimum bias is obtained is correspondingly changed. Shift from left to right in the figure,
The center 18 of the sensitivity distribution also shifts from left to right. Also,
If necessary, by interlocking with the current Ic flowing through the adjusting conductor 22 and slightly changing the magnetically sensitive current Is flowing through the MR film 21, the reproducing characteristics (for example, sensitivity and asymmetric characteristics) are not significantly affected, It is also possible to shift the sensitivity center.

[Third Embodiment] FIG. 8 is a block diagram of a magnetoresistive head used in the third embodiment. In the present embodiment, two electrodes 82 of the MR film 81 are provided on each end, two at a position near the medium facing surface and two at a position far from the medium facing surface. A component a flowing from the upper left to the lower right of the figure and a component b flowing from the lower left to the upper right of the figure are considered as components of the magnetosensitive current, and a diversion ratio between the two can be controlled by an adjustment signal from the outside. When the ratio of the a-component current is large, the current density in the portion of the MR film 81 on the right side of FIG. 8 near the medium facing surface 87 is high. At this time M
Since the R head sensitivity is larger in the portion closer to the medium corresponding surface 87, the center of the sensitivity distribution shifts to the right. On the contrary, when the ratio of the b component current is large, the center of the sensitivity distribution shifts to the left side of the figure. Tracking adjustment is possible by continuously changing the diversion ratio during this period.

As one variation of this type, FIG.
As shown in i), the number of electrodes can be three. In this case, tracking adjustment is performed by adjusting the diversion ratio between the current component between the electrodes 83 and 84 and the current component between the electrodes 83 and 85. In this embodiment, the drive circuit of the magnetoresistive effect head needs to have the function shown in FIG. 9 in addition to the conventional function. The current Is from the constant current power supply is controlled by the shunt ratio controller 91.
It is divided into two current outputs Ia and Ib. Here, the diversion ratio controller 91, according to the tracking control signal 92,
The electric circuit has a function of distributing and outputting current to the circuits a and b. By using such a drive circuit, it becomes possible to shift the sensitivity distribution of the magnetoresistive head shown in FIG. 8 and perform tracking.

[Embodiment 4] FIG. 10 is a block diagram of a magnetoresistive head used in Embodiment 4. In this embodiment, two layers of MR films 101A and 101B are laminated and electrically insulated from each other. Current 10 in the same direction on the two MR films
By causing 2 to flow, a lateral bias is applied to each other.

In such a structure, as shown in FIG. 11, the sensitivity distributions Va of both MR films 101A and 101B are
Vb is symmetrical with respect to the geometric center of the head, and the positions of the sensitivity centers are separated from each other by about several μm. A reproduction signal is obtained by weighted averaging the reproduction signal using a circuit as shown in FIG. Output voltage Va from MR film 101A
The output voltage Vb from the MR film 101B passes through a weighted average calculator 122 to generate a reproduction output 121. The weighting ratio is controlled by the tracking control signal 123. The reproduction signal 121 can be described as follows. V = wVa- (1-w) Vb

Va and Vb are MR films 101A and 10A, respectively.
The output of 1B, w is a parameter that determines the weighting factor.
When w = 1, the reproduction sensitivity distribution matches that of the MR film 101A, and when w = 0, it matches that of the MR film 101B. By changing w, the sensitivity center 18 can be brought to any position between them. FIG.
Shows the sensitivity distributions for various w values. In this way, fine tracking becomes possible.

[Fifth Embodiment] FIG. 14 shows a vertically arranged magnetoresistive head according to a fifth embodiment. In this embodiment, 2
The MR films 141A and 141B of the layers are biased with each other, and the respective sensitivity distributions Va and Vb have peaks in symmetrical directions as shown in FIG. In the conventional vertical system, the two layers of the MR film are electrically short-circuited over the entire surface, and the sensitivity distribution center is fixed at the geometric center.

In this embodiment, an insulating film 142 is provided between the two layers of MR films, the resistance change outputs of both films are taken out separately, and these are weighted and added by a circuit as shown in FIG. Playback signal. The output voltage Va from the MR film 141A and the output voltage Vb from the MR film 141B generate a reproduction output 121 via a weighted average calculator 122. The weighting ratio is controlled by the tracking control signal 123. The reproduction signal 121 can be described as follows. V = wVa + (1-w) Vb

Here, w is a parameter that determines the weighting factor. When w = 1, the reproduction sensitivity distribution is the MR film 141.
In the case of w = 0, which corresponds to that of A, the MR film 141B
Match that of. Fine tracking is possible by adjusting the weighting ratio w.

[Sixth Embodiment] FIG. 17 shows a reproducing head 172.
17A and 17B are configuration diagrams of a magnetic disk device of Example 6 in which the above-described peak position adjusting head is incorporated, FIG. 17A is a plan view, and FIG. 17B is a sectional view taken along line AA ′. In the magnetic disk device, a plurality of magnetic disks 171 are incorporated in a disk spindle 170 directly connected to a spindle motor,
Magnetic heads 172 are arranged so as to face each surface of the magnetic disk, and each magnetic head can access all the positions recorded on the surface of the magnetic disk 171 by one magnetic head actuator 173. it can.

The follow-up control system of the magnetic head is a two-stage servo system shown in FIG. For details of the two-stage servo system, see, for example, IEICE Transactions, Vol.J75-
C-II, No. 11, p.653 (1992). A voice in which the magnetic head actuator 173 is rotationally driven by a peak position adjusting head system (which will be referred to as a "fine system" (including a compensating element) 181) and a voice coil motor (VCM) using the peak position adjusting head of the present invention. The coil motor system 182 (which will be referred to as a coarse system, including a compensating element) has a relationship of operating in cooperation with each other. The compensating element is an element that performs proportional, integral, and derivative operations required to stabilize the operation of each system, and is composed of a gain adjuster, an integrator, and a differentiator, respectively.

The operation will be described below with reference to FIG. A target value r (usually a tracking deviation of 0) is given to the coarse system 182. The VCM operates so that the deviation from the target value becomes zero, and the remaining tracking amount is fed back. Then f
The ine system 181 is given the follow-up remaining amount,
The deviation amount that cannot be tracked by the rse system 182 is tracked. Here, it is assumed that the influence of force interference caused by the operation of each system (stage) is small and can be ignored.

[Embodiment 7] In the above embodiment, fine
The operating band of the system 181 is sufficiently wide, but the coarse system 182 is used.
There is a large difference in the operating band from the operating range, and the dynamic range of the operating range is several hundred nm for fine systems and several meters for coarse systems.
Since it is significantly different from m, the follow-up remaining amount of the coarse system is f
If the in-system operation range is exceeded, the actual operation may not follow the disturbance.

FIG. 19 shows a seventh embodiment in which the dynamic range is continuous in order to solve such a problem.
Magnetic disk device. A notch such as 192 is provided in a part of the guide arm 191, and for example, the piezo element 1
Incorporate 93. As a result, in addition to the operation 194 of the VCM, the operation 195 of the actuator [which will be referred to as a mid (fine movement) system] by the piezo element becomes possible.
Here, the operating range is 5 μm for the mid system and 0.3 μm for the fine system, and the mid system is for the remaining follow-up of the coarse system, and the fine system is for the remaining follow-up of the mid system. An operating range sufficient for tracking correction is secured. The configuration of the tracking control system at this time is, for example, as shown in FIG.
Shall be 0. Figure 1 shows each operation.
This is based on the follow-up operation described in 8. This allows the core
se system 201, mid system 202, fine system 203 3
It is possible for the seed systems to work in concert.

[Embodiment 8] FIG. 21 is a view for explaining an embodiment 8 showing the arrangement of servo patterns of the present invention. In the present invention, since the servo band can be made much wider than the conventional one, it is possible to increase the positioning accuracy by increasing the number of servo signal samples. As a means for realizing this, in addition to the sector servo system on the data surface which has been used in the conventional magnetic disk, a sample servo system in which only the following servo information is sampled is effective.

Sector areas 212 are radially arranged on the data surface 211 of the magnetic disk, and the head 21 of each sector area is arranged.
The pattern of No. 3 is sync.3 as shown in FIG. , I
Each information of servo and data such as D gray code is written. Here, servo indicates servo information, and is, for example, a general dibit pattern staggered with respect to the track center line. On the other hand, in each sector area, sync. And sample servo information 214 composed only of the servo information is discretely arranged. As shown in FIG. 21B, each sample servo information is sync. It is composed of (synchronous) information, servo information, and recording data. Here, the sample servo information 214 has a simple structure such as a pair of die pit patterns as shown in FIG. And servo only occupy an area for several bytes.

The number of samplings of the position information necessary for the operation of the actuator or the like needs to be a sufficient number corresponding to the operating band of the actuator, and generally 5 to 10 times the operating frequency band is sufficient. Are known. That is, the sample frequency of the sample servo information needs to be about 5 to 10 times the operating frequency band of the peak position adjusting means of the present invention, and when the operating frequency band of the peak position adjusting means is set to 20 kHz, it is 100. ~
It is 200 kHz. From the relationship with the disk rotation speed, the number of sample servo information per track is 500.
It is about 3000 pieces.

[0038]

According to the present invention, the high-speed tracking of the magnetoresistive effect head becomes possible.

[Brief description of drawings]

FIG. 1 is a diagram showing a structure of a magnetoresistive effect reproducing head and a sensitivity distribution in a track width direction.

FIG. 2 is a diagram showing a relationship between a magnetosensitive current and a sensitivity center position.

FIG. 3 is a schematic diagram of a head drive circuit according to the first embodiment.

FIG. 4 is a diagram showing a structure of a magnetoresistive effect reproducing head according to a second embodiment.

FIG. 5 is a diagram showing a relationship between an adjustment current Ic and a sensitivity center position.

FIG. 6 is a schematic diagram of a drive circuit for an MR head according to a second embodiment.

FIG. 7 is a diagram showing a bias magnetic field distribution and a reproduction sensitivity distribution in the track width direction according to the second embodiment.

FIG. 8 is a view showing the structure of a magnetoresistive effect reproducing head provided with three or more electrodes.

FIG. 9 is a schematic diagram of a drive circuit for an MR head according to a third embodiment.

FIG. 10 is a diagram showing the structure of a mutual bias type magnetoresistive head according to a fourth embodiment.

FIG. 11 is a diagram showing the sensitivity distribution in the track width direction of the MR head of Example 4.

FIG. 12 is a drive circuit of the MR head of the fourth embodiment.

FIG. 13 is a diagram showing sensitivity distribution in the track width direction of the MR head of Example 4;

FIG. 14 is a diagram showing the structure of a vertical type magnetoresistive head of Example 5;

FIG. 15 is a diagram showing a sensitivity distribution of the MR head of Example 5.

FIG. 16 is a drive circuit of the MR head of the fifth embodiment.

FIG. 17 is a schematic diagram of a magnetic disk device according to a sixth embodiment.

FIG. 18 is a configuration diagram of a servo system according to a sixth embodiment.

FIG. 19 is a schematic diagram of a magnetic disk device according to a seventh embodiment.

FIG. 20 is a configuration diagram of a servo system according to a seventh embodiment.

FIG. 21 is a layout diagram of servo patterns according to an eighth embodiment.

[Explanation of symbols]

11, 21, 81 ... MR magnetic sensing part, 12 ... Magnetization, 13, 2
3,82,83,84,85,143a, 143b, 1
43c ... Electrode, 14 ... Sensitivity distribution, 16 ... Geometric center of magnetic sensitive part, 17 ... Shift amount, 18 ... Sensitivity center, 22 ... Adjustment conductor, 26 ... Constant current power supply, 27 ... Amplifier, 28 ... Tracking control Signal, 61 ... Constant current power source, 62 ... Amplifier,
63 ... Tracking control signal, 91 ... Diversion controller, 92
... Tracking control signal, 101A, 101B, 141
A, 141B ... MR film, 102 ... Magnetosensitive current, 121 ... Reproduction output, 122 ... Weighted average calculator, 123 ... Tracking control signal, 142 ... Insulating film, 170 ... Disk spindle, 171, 201 ... Magnetic disk, 172 ... Magnetic head, 173 ... Voice coil motor, 181, ... fine
System, 182 ... coarse system, 191 ... guide arm,
192 ... Notch, 93 ... Piezo element, 201 ... Coa
rse system, 202 ... mid system, 203 ... fine system, 2
11 ... Magnetic disk data surface, 212 ... Sector area, 2
13 ... sector servo information, 214 ... sample servo information

Claims (12)

[Claims] 1. A magnetoresistive effect reproducing head, a tracking control signal generating means, and a tracking servo means, the tracking servo means of the magnetoresistive effect reproducing head based on the tracking control signal from the tracking control signal generating means. A magnetic disk device comprising a reproducing head sensitivity distribution adjusting means for changing the sensitivity distribution in the track width direction. 2. The magnetic disk drive according to claim 1, wherein the reproducing head sensitivity distribution adjusting means is used as a fine movement track following means. 3. The magnetic disk drive according to claim 2, wherein the reproducing head sensitivity distribution adjusting means is used as a fine movement track following means, and a two-step servo system is provided together with the coarse movement track following means. 4. The reproducing head sensitivity distribution adjusting means is used as a fine movement track following means, and a medium fine movement track following means and a coarse movement track following means are combined into a three-stage servo system. The magnetic disk device described. 5. The magnetic disk device according to claim 4, wherein a voice coil motor is used as the coarse movement track following means, and a piezo element is used as the medium fine movement track following means. 6. The position signal used for the track following means is a combination of the number of disk revolutions and the number of servo marks such that the sampling frequency is 5 to 10 times the operating frequency band of the reproducing head sensitivity distribution adjusting means. 6. A sample servo signal that the user has.
The magnetic disk drive according to any one of 1. 7. A reproducing head sensitivity distribution adjusting means, comprising a magnetic recording head, a magnetoresistive reproducing head, and reproducing head sensitivity distribution adjusting means for changing the sensitivity distribution in the track width direction of the magnetoresistive reproducing head. A magnetic disk device characterized in that a positional deviation between a magnetic recording head and a magnetoresistive effect reproducing head is corrected by. 8. The read head sensitivity distribution adjusting means adjusts a magneto-sensitive current flowing to a magnetoresistive film of a magnetoresistive reproducing head.
7. The magnetic disk device according to claim 7. 9. The magnetoresistive effect reproducing head comprises an adjusting conductor arranged in the vicinity of the magnetoresistive effect film, and the reproducing head sensitivity distribution adjusting means adjusts a current flowing through the adjusting conductor. The magnetic disk device according to claim 1, wherein the magnetic disk device is a magnetic disk device. 10. The magnetic disk drive according to claim 9, wherein the adjusting conductor has a width that varies along the track width direction. 11. A magnetoresistive effect film magnetic sensing part of a magnetoresistive effect reproducing head has three or more electrode terminals, and the reproducing head sensitivity distribution adjusting means adjusts a shunt ratio of a current flowing between the electrode terminals. It is a thing, It is characterized by the above-mentioned.
The magnetic disk drive according to any one of 1. 12. A magnetoresistive effect reproducing head obtains a reproduction output signal by synthesizing signals from two layers of magnetoresistive effect films having different sensitivity distributions, and said reproducing head sensitivity distribution adjusting means comprises 2. 8. The magnetic disk device according to claim 1, wherein a ratio of combining signals from the magnetoresistive film of the layer is adjusted.