JP2004241092A - Magnetic head slider and magnetic disk unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide, in particular, a flying height adjusting slider with the function of adjusting the distance between a magnetic head and magnetic disk, having a magnetic head slider structure for realizing high recording density. <P>SOLUTION: First, a film resistor 4 as a heating device is fully separated from record-reproducing components 2 and 3. Secondly, floating surface is designed so as to increase air pressure generated on the floating surface, due to the projection of a part of the floating surface accompanying energization of the resistor 4. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a magnetic head slider structure for realizing a high recording density of a magnetic disk drive, and more particularly to a flying height adjusting slider having a function of adjusting a distance between a magnetic disk and a magnetic head.
[0002]
[Prior art]
A magnetic disk device has a rotating magnetic disk, and a magnetic head slider (also simply referred to as a slider) mounted with a read / write element and supported and radially positioned by a load beam, and the slider relatively moves on the magnetic disk. To read and write magnetic information recorded on the magnetic disk. The slider floats as an air-lubricated bearing by the wedge film effect of air, so that the magnetic disk and the slider do not directly come into solid contact. In order to increase the recording density of a magnetic disk drive and thereby increase the capacity or reduce the size of the drive, it is effective to reduce the distance between the slider and the magnetic disk, that is, to reduce the slider flying height and increase the linear recording density. is there.
[0003]
Conventionally, in the design of the slider flying height, a flying height margin has been provided so as to prevent the slider from coming into contact with the disk even under the worst conditions, in view of a reduction in the flying height due to processing variations, a difference in atmospheric pressure in use, a temperature difference in use environment, and the like. By realizing a slider with a function to adjust the flying height for each head or according to the usage environment, the above margin can be eliminated, and the flying height of the read / write element can be greatly increased while preventing contact between the slider and disk. Can be reduced to For example, there has been proposed a slider structure in which a heating device formed of a thin film resistor is provided in the vicinity of a recording / reproducing element and a part of the slider is heated and thermally expanded and protruded as necessary to adjust the flying height of the recording / reproducing element. (For example, see Patent Document 1).
[Patent Document 1]
JP-A-5-20635 (page 3).
[0004]
[Problems to be solved by the invention]
First, there is a problem of the life of the reproducing element. Reproduction elements utilizing the magnetoresistance effect (MR effect), which are currently mainstream, are susceptible to heat load, and have the characteristic that the life is shortened if the exposure time to high temperatures is long. The method disclosed in Japanese Patent Application Laid-Open No. Hei 5-20635 is an effective flying height adjustment method. However, when applied to a current recording / reproducing element, a thin film resistor as a heating device is located very close to the recording / reproducing element. Therefore, the life of the reproducing element may be shortened by heating.
[0005]
Second, there is a problem in the flying height adjustment direction. The method disclosed in the publication is a method in which the recording / reproducing element portion is protruded by thermal expansion, so that the flying height is reduced by energization. Regarding the atmospheric pressure (operating altitude), the flying height tends to be large at high pressure (low altitude) where the pressure applied to the air bearing is large, and the flying height tends to decrease as the pressure decreases (high altitude). Therefore, it is necessary to design a floating surface that does not contact even at high altitudes, and it is necessary to always energize at low altitudes and reduce the flying height, but it is more frequently used at low altitudes than at high altitudes. The flying height adjustment direction requires more power than the opposite direction.
[0006]
In summary, reducing the thermal load on the reproducing element and developing a method for increasing the flying height by energization are the two problems to be solved by the present invention.
[0007]
[Means for Solving the Problems]
The first problem is that the thin film resistor as the heating device is sufficiently separated from the recording / reproducing element, and second, the air pressure generated on the floating surface increases due to the projection of a part of the floating surface due to energization of the resistor. The design of the air bearing surface is solved by these two points.
Regarding the first point, the thin film resistor needs to be separated from the read / write element by 0.1 mm or more. When the recording / reproducing element is located at the center of the air outflow end, it is preferable to install a thin film resistor at least 0.1 mm apart on both sides of the recording / reproducing element near the outflow end.
Regarding the second point, the flying surface of a two-step step bearing slider widely used in the industry at present has three substantially parallel surfaces, namely, (1) a rail surface on which a read / write element is installed, (2) ) A shallow groove surface which is a step bearing; and (3) a deep groove surface which is a negative pressure pocket. In recent years, the rail surface has been referred to as an uppermost surface on which a recording / reproducing element is installed (referred to as an element installation surface). A three-step step bearing slider which is divided into two surfaces of an extremely shallow step bearing surface (referred to as an ultra-shallow groove surface) of about 5 nm to 50 nm, and whose floating surface is composed of a total of four parallel surfaces, has been newly proposed. I have. The three-step slider has a small and narrow element mounting surface and a super shallow groove surface slightly lower than the element mounting surface, so that the element mounting surface is the most suitable for the disk regardless of the roll direction inclination of the slider. It can be ensured that the distance is close to each other, which contributes to lowering the flying height of the recording and reproducing element. Further, even if the element installation surface is made smaller, the ultra-shallow groove surface generates air pressure and supports the load, so that there is a feature that the ability to follow the minute waviness of the disk is not impaired.
The thin film resistor is exposed at the surface of the air bearing surface or formed at a position at a certain distance from the air bearing surface in the normal direction. If the position where the thin-film resistor is projected on the air bearing surface is in or near the ultra-shallow groove surface area, when the thin-film resistor is heated by heating and the surroundings are thermally expanded and deformed, the ultra-shallow groove surface faces the disk side. And the air pressure generated on the ultra-shallow groove surface increases, so that the flying height of the entire slider and the flying height of the recording / reproducing element increase. That is, the flying height is adjusted in a direction in which the flying height is increased by energization.
By the means described so far, the flying height adjustment with small power consumption can be realized without affecting the life of the reproducing element. As a result, the flying height margin can be eliminated by adjusting the flying height for each individual head or according to the use environment, and the flying height of the recording / reproducing element can be significantly reduced while preventing the slider from coming into contact with the disk. This contributes to an increase in the recording density of the magnetic disk surface and further to an increase in the capacity or size of the apparatus.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
A magnetic head slider according to an embodiment of the present invention and a magnetic disk drive using the same will be described below with reference to the drawings.
[0009]
FIG. 1 shows a schematic configuration of a magnetic disk drive according to one embodiment of the present invention. The magnetic head slider 1 has a recording / reproducing element for recording / reproducing magnetic information. The magnetic disk 10 stores magnetic information and is rotated by a spindle motor. The magnetic head slider 1 is attached to a leaf spring-shaped load beam, is given a pressing load against the magnetic disk surface by the load beam, and performs a seek operation in the radial direction of the magnetic disk 10 by a voice coil motor together with the load beam. Recording and reproduction are performed on the entire surface of the magnetic disk. The magnetic head slider 1 retreats from the magnetic disk 10 onto the ramp 14 when the apparatus is stopped or when there is no read / write command for a certain period of time.
Although a device having a load / unload mechanism is shown here, a contact start / stop type magnetic disk device in which the magnetic head slider 1 waits in a specific area of the magnetic disk 10 while the device is stopped. The effect of the invention can be obtained similarly.
[0010]
FIG. 2 is a slider perspective view showing the first embodiment of the present invention. The slider 1 has a substrate (wafer) portion 1a of a material typified by a sintered body of alumina and titanium carbide, and a recording / reproducing element and a wiring pattern formed on the substrate by a thin film process, and covered with a hard protective film such as alumina. And a thin film head portion 1b.
[0011]
The slider 1 has a substantially rectangular parallelepiped shape having a length of 1.25 mm, a width of 1.0 mm, and a thickness of 0.3 mm. The slider 1 has an air bearing surface 9, an air inflow end surface 12, an air outflow end surface 13, both side surfaces, and a total of six surfaces. Consists of faces. The air bearing surface 9 is provided with minute steps by a process such as ion milling or etching, and generates air pressure in opposition to a disk 10 (not shown) to serve as an air bearing for supporting a load applied to the back surface. Plays.
[0012]
The air bearing surface 9 is provided with a step as described above, and is classified into four types of substantially parallel surfaces. The element mounting surface 5 closest to the disk, the ultra-shallow groove surface 6 which is about 5 nm deeper than the element mounting surface, the shallow groove surface 7 which is a step bearing surface which is about 150 nm deeper than the element mounting surface, and the deep groove which is about 1 μm deeper than the element mounting surface There are four types of surface 8. As shown, the element installation surface 5, the ultra-shallow groove surface 6, and the shallow groove surface 7 are each divided into a plurality of components 5a, 5b, 5c, components 6a, 6b, and components 7a, 7b. FIG. 3 is an enlarged view of the vicinity of the center of the floating surface on the outflow end side. FIG. 4 shows a view from the air outflow end side. D1, D2, and D3 in FIG. 4 are about 5 nm, about 150 nm, and 1 μm, respectively.
[0013]
When the airflow generated by the rotation of the magnetic disk 10 enters the element mounting surface 5 as the rail surface and the ultra-shallow groove surface 6 from the shallow groove surface 7 as the step bearing, the flow is tapered. Compressed, producing positive air pressure. On the other hand, when the air flow enters the deep groove surface 8 from the rail surface or the shallow groove surface, a negative air pressure is generated due to the expansion of the flow path.
[0014]
The magnetic head slider 1 is designed to fly in such a posture that the flying height at the air inflow end 12 is larger than the flying height at the air outflow end 13. Therefore, the floating surface near the outflow end comes closest to the disk 10. In the vicinity of the outflow end, since the element installation surface 5a protrudes from the surrounding super-shallow groove surfaces 6a, 6b, the shallow groove surface 7a, and the deep groove surface 8, the slider pitch posture and the roll posture do not tilt beyond a certain limit. As far as possible, the element installation surface 5a is closest to the magnetic disk 10. The magnetic head (composed of the recording element 2 and the reproducing element 3) is formed on the element mounting surface 5a in the thin film head portion. At least the element mounting surface 5a is coated with a protective film such as carbon to prevent corrosion of the recording / reproducing element.
[0015]
The method of forming a step of about 5 nm between the element installation surface 5 and the ultra-shallow groove surface 6 is an easy method to obtain by removing the carbon film of about 5 nm by means such as oxygen ashing.
[0016]
Heating devices 4a and 4b using thin-film resistors are formed in the thin-film head portions of the ultra-shallow groove surfaces 6a and 6b using a thin-film process. Although the heating devices 4a and 4b are shown as being exposed on the surface of the floating surface, they may be separated from the surface of the floating surface by a certain distance. In this embodiment, a thin wire having a material of permalloy, a thickness of 0.5 mm and a width of 3 μm was meandered in a region of a depth of 60 μm and a width of 60 μm as a thin film resistor, and a gap was filled with alumina to form a heating element.
[0017]
The feature of the present embodiment over the conventional technique is that the distance D from the reproducing element 3 to the heating device 4a or 4b is 0.1 mm or more. Further, the position of the heating devices 4a and 4b (or the position projected on the air bearing surface) is not the element installation surface 5a but the ultra-shallow groove surfaces 6a and 6b.
[0018]
The purpose of the heating device is to adjust the spacing between the read / write element and the magnetic disk by thermal expansion deformation, and to make the flying height margin useless. In recent years, the flying height margin is designed to be 10 nm or less, so that a maximum variation of the flying height of 10 nm is sufficient. Assuming that the relationship between the amount of thermal expansion deformation and the amount of change in flying height is one-to-one, it is sufficient if the amount of thermal expansion deformation is also 10 nm. According to the results of the head heat transfer analysis and the head deformation analysis based on the heat generated from the thin-film resistor, the thin-film resistor only needs to generate 50 mW of heat in order to cause thermal expansion and deformation of 10 nm. In that case, the temperature rise of 10 ° C. or more is only in the vicinity of the thin film resistor, and the temperature rise is limited at a position separated by 0.1 mm. That is, if the heating device 4 is separated from the reproducing element 3 by 0.1 mm or more, the influence on the life of the reproducing element is very limited, and a highly reliable magnetic head slider can be provided. Note that the relationship between the amount of thermal expansion deformation and the amount of change in the flying height is not strictly one-to-one, but can be brought closer to one-to-one by devising the flying surface design described later.
[0019]
Next, the principle of adjusting the flying height will be described with reference to FIG. 5, taking as an example a case where the variation in the flying height caused by the pressure difference in the use environment is compensated. FIG. 5A schematically shows the positional relationship between the disk 10 and the recording / reproducing elements 2 and 3 under lowland conditions. The flying height of the element under lowland conditions is H0.
[0020]
FIG. 5B shows a positional relationship under high altitude conditions. When the air pressure is low at high altitude, the air pressure generated on the air bearing surface such as the element installation surface 5a becomes smaller as compared with the same floating amount, and the floating amount becomes smaller as compared with the same load. That is, the element flying height H1 is smaller than H0, and the difference is an amount that cannot be ignored compared to the current design flying height. If the design is such that the disk is barely contacted at low altitude, contact between the disk and the slider occurs at high altitude, causing a recording / reproducing error due to slider vibration, a reading error due to thermal asperity, and element damage due to wear. Conversely, if the design does not allow contact even at high altitudes, it must be used with a high flying height at low altitudes, and the recording density cannot be increased.
[0021]
FIG. 5C shows a state in which the heating devices 4a and 4b are energized to thermally deform the ultra-shallow groove surfaces 6a and 6b by the magnetic head slider structure of the present invention under high altitude conditions. By increasing the air pressure generated at the ultra-shallow groove surfaces 6a and 6b, the reduced air pressure at high altitude is compensated, and the element flying height H2 can be made equal to the original element flying height H0.
[0022]
The method of compensating the flying height fluctuation caused by the pressure difference has been described above.However, the method of compensating the flying height fluctuation caused by the temperature difference, the case of canceling the element protrusion due to the heat generation of the recording element, and the head individual The same applies to the case where the flying height variation due to the difference is adjusted.
[0023]
In the conventional method of adjusting the flying height, a heating device is placed near the recording / reproducing element, and is protruded only in the vicinity of the recording / reproducing element. In the case of this method, a design is made so as not to make contact at a high altitude, and at a low altitude, the flying height is increased and the flying height is reduced by an amount corresponding to an increase in the flying height. Considering the location where the magnetic disk device is used, the frequency of low land is higher than that of high land, so that the power supply time or the time required for large input power becomes longer, and the power consumption is large. On the other hand, the flying height adjusting method of the present invention is a method in which the flying surface near the heating device is brought closer to the disk to increase the flying surface area, and the flying height is increased by energization. In the case of this method, a design is made so as not to make contact at a low altitude, and at a high altitude, the floating amount is increased by energizing as much as the floating amount is reduced. Since the frequency of use at high altitude is low (the frequency of use at high altitude is higher when viewed individually, but is higher for the entire model), the required power consumption is small.
[0024]
Next, a method of detecting the flying height will be described. There is also a method of separately providing a sensor for measuring the atmospheric pressure and temperature. However, in a state where all the influences such as the atmospheric pressure, temperature, individual difference, etc. are included, contact does not occur (too close) and an error occurs in reproducing magnetic information ( It is not a problem if the two conditions are satisfied, so it is best to perform feedback control to monitor contact and regeneration errors and adjust the input power to the heating device only when they occur. This is a simple control method. In order to prevent the element from being damaged by the impact of the load, it is effective to energize the heating device to increase the flying height when the slider is loaded on the disk, particularly when the device is started.
[0025]
FIG. 9 shows a control algorithm from the start of the apparatus. A method for detecting contact will be described later. The method of compensating for the flying height variation caused by the atmospheric pressure difference and the flying height variation caused by the individual head difference may be performed only at the time of startup as shown in the figure, but for the flying height variation caused by the temperature difference, at specified time intervals, or Contact and playback errors must be monitored at all times during use.
[0026]
Methods for detecting contact include (1) a method using an acoustic emission (AE) sensor, (2) a method for monitoring thermal asperity, which is noise appearing in a reproduced signal due to contact heat generation, and (3) a slider pivoting by contact frictional force. For example, there is a method of monitoring an off-track signal that is slightly rotated around and causes off-track.
[0027]
On the other hand, for a reproduction error of magnetic information, a so-called bit error rate may be monitored. Unlike a reproduction error, it is difficult to monitor a recording error. However, at the time of recording, the element portion expands due to heat generated by the coil of the recording element and the flying height is generally lower than at the time of reproduction, so that no reproduction error occurs. Under the conditions, there is a low possibility that a recording error occurs.
[0028]
Further, as another method relating to the flying height adjustment, there is a method of in-situ observation of the distance between the reproducing element and the medium using the amplitude of the reproducing signal, and this method can be applied.
[0029]
The advantage that the position of the heating devices 4a and 4b (or the position projected on the air bearing surface) is not the element installation surface 5a but the super-shallow groove surfaces 6a and 6b is that when the heating device 4 is not heated, Even if there is a posture, it is possible to guarantee that the portion closest to the recording / reproducing element in the air bearing surface is the lowest point (point closest to the disk). In other words, the difference between the flying height at the minimum flying height position and the flying height at the recording / reproducing element position is small, and the loss of the flying height is small. Conversely, if the width of the outflow end side edge of the element installation surface is large, the distance between the minimum flying height position and the recording / reproducing element position is large, and the loss of the flying height increases.
[0030]
It is known that when the width of the edge on the outflow end side of the element installation surface is reduced to about 30 μm to about 60 μm, the access performance to the disk is improved. The structure of this embodiment is designed to improve the access performance to the disk. Is also advantageous.
[0031]
When the heights of the super-shallow groove surfaces 6a and 6b in FIGS. 2 to 5 are made the same as the height of the element mounting surface 5a, the loss of the flying height is larger than that of the present embodiment as described above. The effect of the present invention can be obtained in the same manner, although the performance of approaching the vehicle is not improved. That is, since the positions of the reproducing element 3 and the heating device 4 are 0.1 mm or more, the influence on the life of the reproducing element is small, and since the adjustment is performed in the direction in which the flying height is increased by energization, the required power consumption is small.
[0032]
Although the relationship between the amount of thermal expansion deformation and the amount of change in flying height is not strictly one-to-one, if the width of the element installation surface on the outflow end side is made as small as possible, while the width of the ultra-shallow groove surface is made as large as possible. good. In other words, by adjusting the ratio of the load supported on the element installation surface to the load supported on the ultra-shallow groove surface and reducing the ratio of the load supported on the element installation surface as much as possible, the relationship between the thermal expansion deformation amount and the floating amount change amount becomes 1 It can be close to one. FIG. 6 shows a second embodiment of the present invention in which the ratio of the load applied to the element mounting surface 5a is reduced as much as possible. As a result of analyzing the pressure change generated using the area of the element installation surface as a parameter, it is preferable that the area of the element installation surface 5a be 0.005 mm 2 or less.
[0033]
FIG. 7 is an enlarged view near the outflow end of a slider perspective view showing a third embodiment of the present invention. The same numbers as those in the first embodiment indicate the same items. The difference between this embodiment and the first and second embodiments is that the ultra-shallow groove surfaces 6a and 6b on which the heating devices 4a and 4b are installed are separated from the element installation surface 5a and separated by the shallow groove surface 7a. Is a point. In this case, the distance D from the heating devices 4a and 4b to the reproducing element 3 becomes larger than in the first and second embodiments, and the risk that the reproducing element is heated and affects the life is further reduced. Further, the deformation due to thermal expansion is limited to only the super-shallow groove surfaces 6a and 6b, and the element installation surface 5a separated by the shallow groove surface hardly moves. The relationship approaches one to one. The area of the element installation surface 5a is as small as possible, and is preferably set to 0.005 mm 2 or less.
[0034]
When the height of the super-shallow groove surfaces 6a and 6b in FIG. 7 is the same as that of the element mounting surface 5a, the loss of the flying height is larger than that of this embodiment, and the performance of approaching the disk is not improved. However, the effects of the present invention can be similarly obtained.
[0035]
FIG. 8 is an enlarged view near the outflow end of a slider perspective view showing the fourth embodiment of the present invention. The same numbers as those in the first embodiment indicate the same items. The difference between this embodiment and the first to third embodiments is that the ultra-shallow groove surfaces 6a and 6b on which the heating devices 4a and 4b are installed are separated from the element installation surface 5a and separated by the deep groove surface 8. It is. In this case, the distance D from the heating devices 4a and 4b to the reproducing element 3 is further increased as compared with the first to third embodiments, and the risk that the reproducing element is heated and affects the life is further reduced. . Further, the deformation due to thermal expansion is limited to only the super-shallow groove surfaces 6a and 6b, and the element installation surface 5a separated by the shallow groove surface hardly moves. The relationship approaches one to one. The area of the element installation surface 5a is as small as possible, and is preferably set to 0.005 mm 2 or less.
[0036]
In the case where the heights of the super-shallow groove surfaces 6a and 6b in FIG. 8 are the same as those of the element mounting surface 5a, the loss of the flying height is larger than that of this embodiment, and the performance of approaching the disk is not improved. However, the effects of the present invention can be similarly obtained.
[0037]
【The invention's effect】
In the present invention, first, the thin film resistor as the heating device is sufficiently separated from the recording / reproducing element, and second, the air pressure generated on the floating surface increases due to the protrusion of the floating surface due to the energization of the resistor. The floating surface is designed so that the flying height can be adjusted without affecting the life of the reproducing element and requiring small power consumption. As a result, the flying height margin can be eliminated by adjusting the flying height for each individual head or according to the use environment, and the flying height of the recording / reproducing element can be significantly reduced while preventing the slider from coming into contact with the disk. This contributes to an increase in the recording density of the magnetic disk surface and further to an increase in the capacity or size of the apparatus.
[Brief description of the drawings]
FIG. 1 shows a magnetic disk drive on which a magnetic head slider according to the present invention is mounted.
FIG. 2 is a slider according to the first embodiment of the present invention.
FIG. 3 is an enlarged view near a slider outflow end of the first embodiment.
FIG. 4 is a view of the slider of the first embodiment as viewed from an outflow end side.
FIG. 5 is an explanatory view of a flying height adjustment mechanism of the first embodiment.
FIG. 6 is an enlarged view near a slider outflow end of a second embodiment.
FIG. 7 is an enlarged view near a slider outflow end of a third embodiment.
FIG. 8 is an enlarged view near a slider outflow end of a fourth embodiment.
FIG. 9 is a flowchart showing a magnetic head slider control method of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Magnetic head slider, 1a ... Slider substrate part, 1b ... Slider thin film head part, 2 ... Recording element, 3 ... Reproduction element, 4 ... Heating device, 5 ... Element installation surface, 5a, 5b, 5c ... Element installation surface configuration Element 6, ultra-shallow groove surface, 6a, 6b, 6c, ultra-shallow groove surface component, 7 shallow groove surface, 7a, 7b shallow groove surface component, 8 deep groove surface, 9 floating surface, 10 ... magnetic disk, 11 ... magnetic disk device, 12 ... air inflow end surface, 13 ... air outflow end surface, 14 ... ramp, D ... distance between reproducing element and heating device, D1 ... depth of ultra-shallow groove surface from element installation surface D2: Depth of the shallow groove surface from the element installation surface, D3: Depth of the deep groove surface from the element installation surface, H0: Element floating amount at low altitude, H1: Element floating amount when heating is not performed at high altitude, H2 … Flying height when heated at high altitude

Claims (5)

An air bearing surface for floating close to the rotating magnetic disk surface at a constant interval, a recording / reproducing element for recording and reproducing information on and from the magnetic disk, and a distance between the recording / reproducing element and the magnetic disk surface are adjusted by thermal expansion. A magnetic head slider having one or more heating devices for
Three or more surfaces whose air bearing surfaces are substantially parallel, that is, a first surface on which the recording / reproducing element is closest to the magnetic disk during operation, and a predetermined depth from the first surface. And two or more surfaces having
The position where the position of the heating device is projected on the air bearing surface is within a plane having a depth other than the first surface, or the position where the position of the heating device is projected on the air bearing surface is within the first surface. A magnetic head slider separated from a portion where the recording / reproducing element is installed by a surface other than the first surface. An air bearing surface for floating close to the rotating magnetic disk surface at a constant interval, a recording / reproducing element for recording and reproducing information on and from the magnetic disk, and a distance between the recording / reproducing element and the magnetic disk surface are adjusted by thermal expansion. A magnetic head slider having one or more heating devices for
Four planes in which the air bearing surface is substantially parallel, that is, a first surface on which the recording / reproducing element is closest to the magnetic disk during operation, and a depth of about 5 nm to 50 nm from the first surface. And a third surface having a predetermined depth from the second surface, and a fourth surface located further deeper than the third surface,
A magnetic head slider, wherein a position where the position of the heating device is projected on an air bearing surface is within the second surface or within 0.05 mm near the second surface. 3. The magnetic head slider according to claim 2, wherein a depth of a part of the second surface from the first surface is reduced by an operation of the heating device. The pad on which the recording / reproducing element is located in the first surface is not in contact with the second surface or the third surface, or the pad on which the recording / reproducing element is located in the first surface 4. The magnetic head slider according to claim 1, wherein an area of the magnetic head slider is 0.005 square mm or less. A magnetic disk drive comprising the magnetic head slider according to claim 1.

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