JP2000222717A - Magnetic recording medium, method and device for manufacturing same, and magnetic recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the magnetic recording medium which has a small Hc distribution and less errors in its data recording area, its manufacturing method and device, and the magnetic recording device. SOLUTION: The magnetic recording medium and the magnetic recording device using it are characterized by that ΔHc(θ)/ΔHc(r) is <=0.5 in the recording area determined by excluding a distance which is 10% of the radius of the magnetic recording medium from the innermost peripheral and outermost peripheral parts, where ΔHc is the difference between the maximum and minimum values of the coercive force at the same radius position in the circumferential direction and ΔHc(r) is the difference between the maximum and minimum values of the coercive force at the same angle position in the radial direction. Gas is blown from a nozzle 5 to a substrate 2 held on a pedestalate 1 to form a film while the substrate 2 is rotated, thus manufacturing this magnetic recording medium.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium, a method of manufacturing the same, a manufacturing apparatus thereof, and a magnetic recording apparatus, and more particularly, to a thin film type magnetic recording medium capable of obtaining good magnetic characteristics and electromagnetic conversion characteristics. , A manufacturing method thereof, a manufacturing apparatus, and a magnetic recording apparatus.

[0002]

2. Description of the Related Art As is well known, a disk-shaped magnetic recording medium is formed by forming a magnetic layer such as a Co alloy on a non-magnetic disk-shaped substrate. A base film is formed, and a protective film, a lubricating film, and the like are formed on the upper side.

In forming this magnetic layer, the substrate is held by a holding member, and a thin magnetic layer film is formed by a thin film forming method such as sputtering, vapor deposition, plasma CVD, or ion plating. In this conventional method for forming a magnetic layer, the substrate is not rotated in the circumferential direction, and the magnetic layer is formed while maintaining the same posture.

When forming a magnetic layer of a double-sided recording type magnetic recording medium in which magnetic recording layers are formed on both sides of a disk-shaped substrate, the substrate is placed in a sputtering apparatus and held in a non-rotating state. Usually, sputtering is performed by a target arranged on the plate surface.

In a magnetic recording apparatus having a disk-shaped magnetic recording medium, as is well known, a magnetic head is moved in a direction including a radial direction of the magnetic recording medium to transfer information to a target area on a substrate. It is configured to read and write.

[0006]

A conventional magnetic recording medium manufactured by forming a layer such as a magnetic layer in a non-rotating state has a distance of 10% of the radius of the disk-shaped magnetic recording medium at the innermost circumference, In the recording area other than the outermost peripheral portion, the difference between the maximum and minimum values of the circumferential coercive force at the same radial position is ΔHc (θ), and the maximum and minimum of the radial coercive force at the same angular position. When the difference between the values was ΔHc (r), ΔHc (θ) generally tended to be larger than ΔHc (r), but this was not a problem.

[0007] With the recent increase in the amount of information and the demand for smaller and lighter devices, the linear recording density and track density have increased.
As the area per bit becomes smaller, the effects of ΔHc (θ) and ΔHc (r) which have not been a problem until now cannot be ignored. In particular, since data tracks are recorded concentrically and data in the circumferential direction are continuously read, the Hc characteristics in the circumferential direction are very important from the viewpoint of signal processing such as waveform equalization. .

The present invention relates to a magnetic recording medium having a small Hc distribution in the circumferential direction, that is, stable magnetic and electric properties in the circumferential direction, a manufacturing method and a manufacturing apparatus capable of manufacturing the same at low cost, and a magnetic recording medium. It is an object to provide a magnetic recording device using a medium.

[0009]

According to the magnetic recording medium of the present invention, in a magnetic recording medium in which a thin film having at least a magnetic layer is formed on a plate surface of a disk-shaped substrate, a distance of 10% to a radius of the magnetic recording medium is set. The difference between the maximum value and the minimum value of the coercive force in the circumferential direction at the same radial position in the recording area excluding the innermost and outermost portions is defined as ΔHc (θ). When the difference between the maximum value and the minimum value of the coercive force is ΔHc (r), the value of ΔHc (θ) / ΔHc (r) is 0.5 or less.

[0010] Such a magnetic recording medium has an Hc in the circumferential direction.
The distribution is small and the magnetic and electrical properties in the circumferential direction are stable.

The difference between the maximum value and the minimum value of the coercive force of the recording area is 20% or less of the average value of the coercive force, and the value of ΔHc (θ) / ΔHc (r) is 0.3 or less. Is particularly effective for the error characteristics of the magnetic recording medium of the submicron track width class in which the influence of the modulation on the error rate is greater.

This magnetic recording medium can be easily manufactured by a method and an apparatus for rotating a substrate in a circumferential direction in a step of forming at least one layer.

In order to rotate the substrate in the circumferential direction in this film forming step, the outer peripheral edge of the substrate is held, the substrate is held rotatably in the circumferential direction, and a rotational force is applied to the substrate. This is preferable because films can be simultaneously formed on both surfaces.

As the rotational force applying means, a nozzle that blows a gas onto the plate surface of the substrate, a member that contacts the substrate and applies a rotational force, or the like can be used. The gas is preferably an atmosphere gas or a source gas in the film forming apparatus, or a non-reactive gas that does not impair the film formation.

Examples of the member that rotates by contacting the substrate include a roller, an endless rotating belt, and an ultrasonic motor. Further, a member such as a piezoelectric element or a spring that reciprocates along the outer peripheral edge of the substrate can be used. The member for holding the substrate itself may be an ultrasonic motor.

The substrate may be rotatably held, and may be rotated by applying a rotational force prior to film formation, and may be rotated by inertia during the film formation process. According to this method, there is an effect that no foreign matter (dust or the like) is generated from the driving member during the film forming period.

This substrate preferably rotates at a constant speed, but the number of rotations may change over time. In order to keep the substrate rotation speed constant, for example, a part with no relation to the recording area of the disk, such as a chamfer part, create a part with a different gloss, and read it with a reflective sensor to detect the rotation speed, A method of controlling the detected rotation speed to be constant or the like can be adopted.

In the present invention, the substrate may be rotated when forming the underlayer or any one of the intermediate layer, the magnetic layer, and the protective layer located between the magnetic layer and the underlayer. Preferably, the substrate is rotated during the formation of the magnetic layer, and more preferably, the substrate is rotated during the formation of the magnetic layer and the layer in contact therewith. By rotating the substrate in all the sputtering steps, a more suitable magnetic recording medium can be manufactured.

A magnetic recording apparatus according to the present invention includes the magnetic recording medium according to the present invention, driving means for rotating the magnetic recording medium, a magnetic head, and means for moving the magnetic head. The moving means reads or reads / writes information by moving the magnetic head in a direction including the radial direction of the magnetic recording medium.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As a non-magnetic substrate of the magnetic recording medium of the present invention, in addition to an Al alloy substrate containing Al as a main component, such as an Al-Mg alloy, ordinary soda glass, soda lime glass, aluminosilicate Any non-magnetic substrate can be used as long as it is a non-magnetic substrate, such as a glass, a glass such as a borosilicate glass and a crystallized glass, a metal such as silicon and titanium, an alloy, a ceramic, and a substrate made of various resins. Among them, it is preferable to use an Al alloy substrate or a glass substrate such as crystallized glass. This substrate has a ring shape with a hole in the center.

In the manufacturing process of a magnetic disk, it is usual to wash and dry the substrate first, and in the present invention, from the viewpoint of ensuring the adhesion of each layer, it is necessary to wash and dry the substrate before its formation. Is desirable.

In manufacturing the magnetic recording medium of the present invention,
It is preferable to form a nonmagnetic metal coating layer such as NiP on the surface of the nonmagnetic substrate.

Techniques for forming the nonmagnetic metal coating layer include electroless plating, sputtering, vacuum deposition, and the like.
A method used for forming a thin film such as a CVD method can be used. In the case of a substrate made of a conductive material, it is possible to use electrolytic plating. The thickness of the nonmagnetic metal coating layer may be 50 nm or more. However, considering the productivity of the magnetic disk medium, etc.
It is preferably not more than 000 nm. More preferably, it is 100 nm or more and 15,000 nm or less.

The surface of the substrate or the surface of the substrate on which the nonmagnetic metal coating layer is formed may be subjected to texturing, for example, concentric texturing. Concentric texturing is, for example, mechanical texturing using loose abrasive grains and texture tape, texturing using laser light, or the like, or by polishing them together in the circumferential direction, in the circumferential direction of the substrate. To form a large number of microgrooves.

As the type of free abrasive grains for mechanical texturing, diamond abrasive grains, particularly those whose surfaces have been subjected to a graphitization treatment, are preferred. Alumina abrasive grains are widely used as abrasive grains used in mechanical texturing, but diamond abrasive grains have extremely good performance, especially from the viewpoint of orienting the axis of easy magnetization along the texturing grooves. Demonstrate. The cause is not clear at this time,
Extremely reproducible results have been obtained.

The surface of the substrate does not basically affect the effect of the present invention no matter what value the surface roughness (Ra) takes, but the fact that the head flying height is as small as possible is necessary for realizing high density magnetic recording. Is effective, and one of the features of these substrates is excellent surface smoothness.
a is preferably 2 nm or less, more preferably 1 nm or less, and particularly preferably 0.5 nm or less. However, this Ra shall mean the case where it measures using the stylus type surface roughness meter. At this time, the tip of the needle for measurement has a radius of about 0.2 μm.

An intermediate layer such as a Cr layer, a Cr alloy layer containing Cr as a main component, a chromium oxide layer, or a Cu layer may be formed on the nonmagnetic substrate or the nonmagnetic coating layer such as Ni-P, if necessary. After formation, a magnetic layer is formed.

As the intermediate layer, in addition to the pure Cr layer, V and V are added for the purpose of crystal matching with the magnetic layer.
Ti, Mo, Zr, Hf, Ta, W, Ge, Nb, S
An alloy layer to which second and third elements such as i, Cu, and B are added, and a Cr oxide layer are preferable. Above all, pure Cr layer, Ti, M
A Cr alloy layer containing o, W, V, Ta, Si, Nb, Zr and Hf is preferable. The content of the second and third elements varies depending on the respective elements, but is generally 1 atomic% to 50 atomic%, preferably 5 atomic% to 30 atomic%, more preferably 5 atomic% to 20 atomic%. Atomic% range.

The thickness of the intermediate layer may be any thickness sufficient to exhibit anisotropy, and is usually 0.1 to 50 nm, preferably 0.3 to 30 nm, and more preferably 0.5 to 30 nm. 10 nm. Substrate heating may or may not be performed when forming a metal film containing Cr as a main component.

The magnetic layer is usually made of pure Co or Co-
P, Co-Ni-P, Co-Ni, Co-Sm, Co-
Cr-Ta, Co-Ni-Cr, Co-Ni-Pt, C
It is preferable to use a Co alloy magnetic material generally used as a magnetic material such as o-Cr-Pt or Co-Cr-Ta-Pt. Ni, Cr, P
A material to which an element such as t, Ta, W, or B or a compound such as SiO ₂ is added may be used. The thickness of the Co alloy magnetic layer is arbitrary, but is usually 10 to 100 nm, preferably 30 to 70 nm.
It is.

The magnetic layer may have a laminated structure of two or more types. An intermediate layer of non-magnetic CoCr or the like may be provided between the underlayer containing Cr as a main component and the magnetic layer.

The method for forming each layer of the magnetic recording medium is arbitrary, and for example, a physical vapor deposition method such as a direct current (magnetron) sputtering method, a high frequency (magnetron) sputtering method, an ECR sputtering method, and a vacuum vapor deposition method is used. No.

The conditions for the film formation are not particularly limited, and the ultimate vacuum, the substrate heating method and the substrate temperature, the sputtering gas pressure, the bias voltage, etc. may be appropriately determined by the film forming apparatus. For example, in the case of sputtering film formation, usually, the ultimate vacuum degree is 1 × 10 ⁻⁶ Torr or less, the substrate temperature is from room temperature to 400 ° C., and the sputtering gas pressure is 1 × 1.
0 ^{−3 to} 20 × 10 ⁻³ Torr, and the bias voltage is generally 0 to −500V.

In film formation, it is generally preferable to heat the nonmagnetic substrate to about 100 to 350 ° C. in order to promote the segregation of Cr in the magnetic layer. Substrate heating may be performed before the formation of the underlayer, and when a transparent substrate having a low heat absorption is used, an underlayer containing Cr as a main component is formed in order to increase the heat absorption. Heat the substrate and then C
An o-alloy magnetic layer may be formed.

On this magnetic layer, a protective layer is formed by a method such as vapor deposition, sputtering, plasma CVD, ion plating, or a wet method, and then a lubricating layer is formed. Examples of the protective layer include carbonaceous layers such as C (carbon), hydrogenated C, nitrogenated C, Amorphous C, SiC, and TiC, and SiO ₂ and Zr _2.
Although a commonly used protective layer material such as an oxide such as O ₃ and Al ₂ O ₃ and a nitride such as SiN and TiN can be used, C or hydrogenated C is preferable. Note that the protective layer may be composed of two or more layers. The thickness of the protective layer is 1
-50 nm, particularly preferably 5-30 nm. Examples of the lubricant used for the lubricating layer include a fluorine-based lubricant, a hydrocarbon-based lubricant, a mixture thereof, and the like, and usually form the lubricating layer with a thickness of 1 to 4 nm.

The magnetic recording medium of the present invention is manufactured by forming a magnetic layer and other necessary layers on a substrate as described above. Each layer is formed by a vapor phase method such as sputtering, vacuum vapor deposition, or CVD. When forming by the method, the substrate is rotated continuously or intermittently in the
Hc (θ) / ΔHc (r) is 0.5 or less.

A magnetic recording apparatus according to the present invention includes the magnetic recording medium according to the present invention, a head, and means for moving the head.

The magnetic recording device includes a shaft for fixing one or more magnetic recording media in a skewered manner,
A motor for rotating a magnetic recording medium joined to the shaft via a bearing, a magnetic head, a head arm to which the head is attached, and moving the head to an arbitrary position on the magnetic recording medium via the head arm An example is a magnetic recording device having an actuator that can be driven.

When the reproducing section of the magnetic head is constituted by an MR head, a sufficient signal intensity can be obtained even at a high recording density, and 2 G / inch 2 can be obtained.
It is possible to realize a magnetic recording device having a high recording density of bits or more. Also, the magnetic head is used with a flying height of 0.
When flying at a height lower than the conventional height of not less than 01 μm and less than 0.05 μm, the output is improved and a high device S / N is obtained, and a large-capacity and high-reliability magnetic recording device can be provided. The recording density can be further improved by combining a signal processing circuit based on the maximum likelihood decoding method. For example, when recording / reproducing at a recording density of not less than 10 kTPI, not less than linear recording density of 200 kFCI, and not less than 2 Gbits per square inch, Also obtains a sufficient S / N ratio.

The reproducing section of the magnetic head is composed of a plurality of conductive magnetic layers which generate a large resistance change due to a relative change in their magnetization directions due to an external magnetic field, and a conductive layer disposed between the conductive magnetic layers. The signal strength can be further increased by using a GMR head made of a conductive non-magnetic layer or a GMR head using the spin valve effect, so that the signal strength is 3 Gbits / sq.
A highly reliable magnetic recording device having a linear recording density equal to or higher than CI can be realized.

FIG. 1 is a front view of the inside of the apparatus for manufacturing a magnetic recording medium according to the embodiment, FIG. 2 is a sectional view taken along the line II-II of FIG. 1, and FIG. It is sectional drawing which follows the III line.

A plurality of claws 3 are provided above the pedestrate 1.
These claws are arranged so as to occupy positions along the outer periphery of the magnetic recording medium 2. On the upper surface of each of the claws 3, a groove having a size and shape such as a V-shape or a U-shape, which holds the substrate by entering the outer peripheral edge thereof, is formed.

The substrate 2 is placed on these claws 3 so that the plate surface is vertical, and the substrate 2 is inserted into the chamber 6. A pair of targets 9 are arranged in the chamber 6 so as to face both surfaces of the substrate 2. Each target 9
Behind the backing plate 8 and magnetron 7
Are sequentially arranged, and a thin film layer can be formed on the substrate 2 by magnetron sputtering. The pedestrate 1 is provided with a bias application point 4.

The nozzle 5 is located immediately adjacent to the outer peripheral edge of the substrate 2.
Is arranged. In this embodiment, the nozzle 5 is disposed immediately below the right end portion of the substrate 2 in FIG. 1 and is arranged so as to blow gas upward along the right end side of the substrate 2. The gas blown out from the nozzle 5 flows upward along both surfaces of the right end portion of the substrate 2, so that a rotational force in the counterclockwise direction in FIG. 1 is applied to the substrate 2, and the substrate 2 rotates.

As this gas, an atmosphere gas at the time of sputtering is suitable, and usually argon is used. It should be noted that the gas is exhausted from the chamber 6 with an exhaust amount corresponding to the amount of the gas jetted.

In this embodiment, the nozzle 5 is disposed only at one position on the right end side in FIG. 1, but it may be disposed at another position or at two or more positions. The direction in which the gas is blown out from the nozzle 5 may be reversed.
Further, two or more nozzles may be arranged at one place. Gas may be blown out from separate nozzles toward each disk surface of the substrate 2.

FIG. 4 shows an apparatus for manufacturing a magnetic recording medium according to another embodiment, in which a substrate 2 is mounted on a plurality of rollers 10. A belt 11 is stretched between the rollers 10 in order to link the rollers 10.
This belt 11 is hung on a belt drive pulley (not shown),
The substrate 2 is rotated by rotating each roller 10 by rotating the pulley.

FIG. 5 shows the apparatus shown in FIG. 4 in which the driving pulley is omitted, and instead, the driving wheel 12 is brought into contact with one roller 10 and the driving wheel 12 is rotated by a motor 13. Similarly, when each roller 10 rotates, the substrate 2 rotates.

FIG. 6 omits the drive wheels 12 and the motor 13 in FIG. 5 and replaces one roller 10 with a windmill 15 instead. The substrate 2 is rotated by blowing gas from the nozzle 14 onto the windmill 15 to rotate the roller 10.

[0050]

EXAMPLE 1 A thin film was formed on a substrate by the manufacturing apparatus shown in FIG. 1 to manufacture a magnetic recording medium. 1 is located vertically below the center of the substrate 2 and the left and right claws 3 are separated from each other by 55 ° (as the central angle of the substrate 2). . The V-shaped opening angle of the groove on the upper surface of the claw 3 was 120 °. A nozzle 5 having an inner diameter of the outlet of 2 mm is disposed at a position 65 ° to the right of the center claw 3 and A
r gas is blown out at a rate of 6 L / min to remove the substrate 200
Rotated at rpm.

As a non-magnetic substrate, an aluminum substrate having an outer diameter of 3.5 inches was placed on the claws 3 and then moved into the chamber 6, and the inside of the chamber 6 was evacuated by a vacuum pump. While rotating the disk at the above rotation speed, a NiP alloy layer was 150 nm as an underlayer, and CoCr was formed on the underlayer.
Using the layer as an intermediate layer, a ferromagnetic alloy thin film of about 20 nm and a Co—Cr—Pt alloy was sequentially formed to a thickness of 30 nm.
On this magnetic recording layer, a hydrogenated carbon film was formed as a protective layer by sputtering. After the end of the sputtering, a lubricant layer is provided on the protective layer, and has a magnetic property of 2500 [Oe].
A 90 [G μm] class magnetic recording medium was obtained.

The obtained magnetic recording medium was written at a maximum recording frequency of 6 MHz using a Guzik recording head having a writing width of 2.4 μm, and a reading gap width of 1.9.
Using a μm head, the data was read, the output threshold for each of the predicted determination values was changed, and the error was measured to measure the error rate.

In order to measure the Hc of the disk for which the error rate was measured, a distance of 10% from the innermost circumference to a position 10% from the innermost circumference in the radial direction from the outermost circumference to the radius of the magnetic recording medium. 8m in diameter every 8mm in the radial direction, every 30 degrees in the circumferential direction up to the part
m VSM (VSM-
Hc was measured using P7), and ΔHc (θ),
Table 1 shows the results of determining ΔHc (r).

Comparative Example 1 A magnetic recording medium was obtained in the same manner as in Example 1 except that the disk was not rotated in the sputtering step of the ferromagnetic alloy thin film, and the same evaluation was performed. Table 1 shows the results.

[0055]

[Table 1]

From this example and comparative example, ΔHc (θ)
It can be seen that the error rate is improved for media with a small / ΔHc (r).

[0057]

As described above, according to the present invention, there are provided a magnetic recording medium and a magnetic recording apparatus having a small Hc distribution in a data recording area and having very few errors. According to the manufacturing method and the manufacturing apparatus of the present invention, this magnetic recording medium can be manufactured efficiently.

[Brief description of the drawings]

FIG. 1 is a front view of the inside of a magnetic recording medium manufacturing apparatus according to an embodiment.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a sectional view taken along the line III-III in FIG. 1;

FIG. 4 is a schematic view of an apparatus for manufacturing a magnetic recording medium according to another embodiment.

FIG. 5 is a schematic view of an apparatus for manufacturing a magnetic recording medium according to still another embodiment.

FIG. 6 is a schematic view of an apparatus for manufacturing a magnetic recording medium according to still another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pedesterate 2 Substrate 3 Claw 5 Nozzle 10 Roller 11 Belt 12 Drive wheel 13 Motor 15 Windmill

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G11B 5/85 G11B 5/85 Z (72) Inventor Yoshinori Seki 1000 Kamoshida-cho, Aoba-ku, Yokohama-shi, Kanagawa Mitsubishi 4K029 AA02 AA09 BA06 BA07 BA12 BA13 BA24 BA25 BA34 BB02 BC06 BD11 CA01 CA05 DC04 DC18 DC34 DC35 DC39 DC48 JA02 JA08 5D006 BB07 BB08 DA03 EA03 FA09 5D112 AA05 AA24 FA01 KK01KK06

Claims (11)

[Claims] 1. A magnetic recording medium having at least a magnetic layer on a plate surface of a disk-shaped substrate, wherein a distance of 10% of a radius of the magnetic recording medium is excluded from an innermost circumference and an outermost circumference in a recording area. The difference between the maximum value and the minimum value of the circumferential coercive force at the same radial position is ΔHc (θ), and the difference between the maximum value and the minimum value of the radial coercive force at the same angular position is ΔHc.
A magnetic recording medium wherein the value of ΔHc (θ) / ΔHc (r) is 0.5 or less when (r). 2. The recording medium according to claim 1, wherein a difference between a maximum value and a minimum value of the coercive force of the recording area is not more than 20% of an average value of the coercive force of the entire recording area, and the ΔHc (θ) / Δ
A magnetic recording medium, wherein the value of Hc (r) is 0.3 or less. 3. A method of manufacturing a magnetic recording medium having a film forming step of forming at least a magnetic layer on a plate surface of a disk-shaped substrate, wherein the substrate is rotated in a circumferential direction in the film forming step of at least one layer. A method for manufacturing a magnetic recording medium, comprising: 4. The method for manufacturing a magnetic recording medium according to claim 3, wherein the substrate is rotated at least in a step of forming the magnetic layer. 5. The method for manufacturing a magnetic recording medium according to claim 3, wherein the substrate is rotated in at least a step of forming a magnetic layer and a layer in contact with the magnetic layer. 6. The method of manufacturing a magnetic recording medium according to claim 3, wherein the substrate is rotated in the step of forming all the layers. 7. The method for manufacturing a magnetic recording medium according to claim 3, wherein the film forming step is a step of simultaneously forming a film on both surfaces of the disk. 8. An apparatus for manufacturing a magnetic recording medium, comprising: holding means for holding an outer peripheral portion of a disk-shaped substrate; and means for providing a thin film on a plate surface of the substrate. An apparatus for manufacturing a magnetic recording medium, which holds a substrate so as to be rotatable in a circumferential direction and provides a rotational force to the substrate. 9. The magnetic recording medium manufacturing apparatus according to claim 8, wherein the means for applying a rotational force has a nozzle for applying a rotational force by blowing a gas to the substrate. 10. An apparatus according to claim 8, wherein said means for applying a rotational force is a member that applies a rotational force by contacting said substrate. 11. A magnetic recording apparatus comprising: a magnetic recording medium; driving means for driving the magnetic recording medium to rotate; a magnetic head; and means for moving the magnetic head. 3. A magnetic recording device, which is the magnetic recording medium according to 2.