JP3789101B2 - Magnetic recording apparatus and magnetic recording writing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic recorder and magnetic recording/writing method wherein a high density is achieved and writing mistakes are limited. <P>SOLUTION: This magnetic recorder is provided with a magnetic recording medium 11 having a plurality of recording cells 12 cyclically arrayed along a recording track direction and nonmagnetic areas 13 for separating the recording cells 12, a magnetic field application recording means 16a for applying a magnetic field to the magnetic recording medium 11 to record information in the recording cell 12, a detection means 19 for detecting a leakage magnetic field 1d generated by application of the magnetic field of the magnetic field application recording means 16a, and control means 3, 4 for controlling a recording timing by the magnetic field application recording means 16a based on the detection of the leakage magnetic field 1d. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a magnetic recording apparatus and a magnetic recording method, and more particularly to a magnetic recording apparatus and a magnetic recording method capable of high-density recording.
[0002]
[Prior art]
The information handled by users has increased remarkably due to dramatic improvements in information devices such as personal computers. Under such circumstances, the expectation for a recording / reproducing apparatus having a recording density significantly higher than that of the prior art is increasing. In order to improve the recording density, it is necessary to reduce the size of one recording mark, which is a unit for writing a record on a recording medium. However, miniaturization of recording marks is facing a great difficulty in the conventional recording / reproducing apparatus.
[0003]
For example, in the case of magnetic recording using a magnetic recording medium such as a hard disk device, a polycrystalline body having a wide particle size distribution is used for the recording layer. However, due to thermal fluctuations of the crystal, recording becomes unstable with a polycrystal having a small grain size. If the recording mark is large, there is no problem, but if the recording mark is small, recording instability and noise increase. This is because the number of crystal grains contained in the recording mark is reduced. In order to prevent this problem, it is sufficient to use a medium that is strong against thermal fluctuation and has small crystal grains. However, such a medium requires a very large magnetic field for writing, resulting in a problem that writing cannot be performed.
[0004]
Resistant to thermal fluctuation, polycrystalline media with small crystal grains and SiO ₂ For a granular medium in which fine particles are dispersed in such a matrix, a method has been proposed in which the recording is maintained by heating and reducing the coercive force to write and quenching. This method is called heat-assisted magnetic recording. Examples of means for applying heat include a method of irradiating near-field light and a method of irradiating an electron beam. These methods are advantageous for high-density recording because the heating spot can be reduced. However, in heat-assisted recording, the timing of application of heat and recording magnetic field is extremely difficult, and even if a signal is written with a recording magnetic field by heating to lower the coercive force, the recording is erased if rapid cooling is not successful.
[0005]
On the other hand, as a countermeasure against thermal fluctuation, a patterned medium is proposed in which a recording material is divided in advance by a non-recording material, and a single recording material particle having a relatively large volume is recorded and reproduced as a single recording cell. (S.Y. Chou et al., J. Appl. Phys., 76 (1994) pp6673; US Patent 5,820,768 and 5,956,216; R. H. M. New et al., J. Vac. Sci.Technol., B12 (1994) pp 3196; However, in the case of patterned media, since the recording cells are fixed, there is a problem that a recording error tends to occur if the recording timing is shifted.
[0006]
[Problems to be solved by the invention]
As described above, the patterned media is an effective means for realizing the Tbpsi-class recording density, but the control of the recording timing shift is not sufficient.
[0007]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a magnetic recording apparatus and a magnetic recording method that can increase the density and have few writing errors.
[0008]
[Means for Solving the Problems]
In order to solve the above-described problem, the first magnetic recording apparatus of the present invention has a plurality of recording cells periodically arranged along the recording track direction and a nonmagnetic region for separating the recording cells. A magnetic recording medium, a magnetic field application recording means for applying a magnetic field to the magnetic recording medium to record information in the recording cell, a detection means for detecting a leakage magnetic field generated by application of the magnetic field of the magnetic field application recording means, And a control means for controlling the recording timing by the magnetic field application recording means based on the detection of the leakage magnetic field.
[0011]
In each of the present invention described above, it is desirable to have the following configuration.
[0012]
(1) In the magnetic recording medium, the centers of the two nearest recording cells located on recording tracks adjacent to each other are shifted by 1 / n period (n is an integer of 2 or more) along the recording track direction. Being.
[0013]
(2) In the magnetic recording medium, the centers of the two nearest recording cells located on the recording tracks adjacent to each other are shifted by a half period along the recording track direction.
[0014]
(3) The recording cell comprises a perpendicular magnetic recording layer, and the magnetic recording medium has a soft magnetic layer under the recording cell.
[0015]
(4) The magnetic field application recording means has a single pole head.
[0016]
(5) The detection means also detects and reads information recorded in a recording cell of the magnetic recording medium.
[0017]
Further, the first magnetic recording method of the present invention performs magnetic recording on a magnetic recording medium having a plurality of recording cells arranged periodically along the recording track direction and a nonmagnetic region separating the recording cells. A magnetic field is applied to the magnetic recording medium to record information in the recording cell, a leakage magnetic field generated by applying a magnetic field of the magnetic field application recording means is detected, and the leakage magnetic field is detected based on the detection of the leakage magnetic field. The recording timing by the magnetic field application recording means is controlled.
[0018]
Further, the second magnetic recording method of the present invention performs magnetic recording on a magnetic recording medium having a plurality of recording cells arranged periodically along the recording track direction and a nonmagnetic region separating the recording cells. A method of performing recording on the recording cell by applying a current magnetic field to the magnetic recording medium, detecting a current change in the magnetic field application recording means caused by application of the current magnetic field of the magnetic field application recording means, The recording timing by the magnetic field application recording means is controlled based on the detection of the current change.
[0020]
In such a magnetic recording method of the present invention, it is desirable to have a desirable configuration of the magnetic recording apparatus described above.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0022]
First, problems with patterned media will be described. In recording on a patterned medium, when the pattern of a recording cell having a periodic structure and the writing timing of the magnetic field applying unit are once shifted, for example, the magnetic field applying unit does not have a recording cell immediately below the magnetic field applying unit. Will continue to be applied. In such a state, writing failure occurs in a considerably large number of recording cells.
[0023]
On the other hand, according to the magnetic recording apparatus and the magnetic recording method of the present invention, the magnetic recording writing means (magnetic field application recording means) for recording writing and the magnetic recording writing means can write information in the recording cell. Detecting a write failure in a very short time by having a detecting means capable of detecting a signal indicating a write at substantially the same time as writing and a controller for controlling the write timing by the magnetic recording writing means. By correcting the timing, it is possible to reduce the number of recording cells that have failed to be written.
[0024]
In the magnetic recording medium used in the present invention, the centers of the two nearest recording cells located on the recording tracks adjacent to each other have a 1 / n period (n is an integer of 2 or more), particularly 1 / n along the track direction. It is preferable that it is shifted by two cycles. In such a magnetic recording medium, the distance between the recording cells can be increased, and erroneous recording on other tracks can be prevented. Such a magnetic recording medium can be easily manufactured using self-assembled molecules.
[0025]
The detection means used in the present invention preferably includes a magnetic sensor for reading a signal or a measuring device for a current flowing in the magnetic writing means. A high-sensitivity GMR or TMR element is preferable for the magnetic sensor. The magnetic writing means is preferably a magnetic field applying means such as a magnetic head or a magnetic probe that can generate a high-intensity magnetic field, or a spin injection means such as a spin head or a spin probe that injects electrons having a unidirectional spin.
[0026]
In a patterned medium, unlike a normal magnetic medium, a non-magnetic portion and a recording cell that is a magnetic material have a periodic structure. Therefore, the magnetic field applied from the magnetic field applying means such as the magnetic head and the magnetic probe and the magnetic field shape formed by the recording medium are different between the case where the magnetic field applying means is on the recording cell and the non-magnetic portion. The detection means detects this difference in magnetic field shape. In other words, when the magnetic field applying means is on the recording cell, writing is successful, a magnetic circuit is formed between the magnetic field applying means and the recording medium, and the leakage magnetic field of the magnetic field applying means is small. On the other hand, when the magnetic field applying means is on the nonmagnetic part, the leakage magnetic field becomes large.
[0027]
The detection means in the present invention detects these magnetic field differences. That is, in the case of reading a signal using a magnetic sensor, when the magnetic field applying unit is on the recording cell, the writing is successful and a magnetic circuit is formed between the magnetic field applying unit and the recording medium. Since the leakage magnetic field of the applying means is small, the signal pulse to be detected is small. On the other hand, in the state where the magnetic field applying means is on the non-magnetic portion, writing is not successful and the leakage magnetic field becomes large, so that the signal pulse to be detected becomes large. In this case, the sign of the signal pulse changes depending on the direction of the magnetic field of the magnetic field applying means.
[0028]
When the measuring device for the current flowing in the coil of the magnetic field applying means is used as the detecting means, the magnetic circuit is formed between the magnetic field applying means and the recording medium by the successful writing when the magnetic field applying means is on the recording cell. Since the electromotive force opposite to that at the time of recording / writing is induced in the coil, the detected current pulse becomes small. On the other hand, when the magnetic field applying means is on the nonmagnetic portion, writing is not successful and the detected current pulse becomes large.
[0029]
When performing magnetic recording writing using spin reversal of the magnetic recording medium by the current injection means described in Japanese Patent Application No. 2001-284467, the writing and current injection correspond to each other. It is possible to detect signals with sensitivity.
[0030]
These detecting means can detect whether or not the writing is successful almost simultaneously with the magnetic recording writing depending on the time constant.
[0031]
In the recording medium of the present invention, it is preferable that the recording cell is a perpendicular magnetic recording medium, has a soft magnetic layer below the recording cell, and has a single pole head as magnetic recording writing means. The perpendicular magnetic recording medium is more suitable for higher density than the longitudinal recording medium, and the one having a soft magnetic layer below the recording cell and the single pole head as the magnetic recording writing means has a magnetic field in the recording cell. Are easily concentrated, and a magnetic circuit is easily formed between the magnetic recording writing means and the recording medium.
[0032]
The relative position of the magnetic recording writing means with respect to the magnetic recording medium is adjusted by a driving device, for example, an actuator including a piezoelectric element.
[0033]
The controller of the present invention controls the timing of writing by the magnetic recording writing means so that information can be written correctly based on a signal detected by the detecting means and indicating whether or not information has been written to the recording cell. A system LSI is used as a specific controller. More preferably, the controller has a function of self-learning the optimum system by trying writing and reading after assembling the magnetic recording apparatus.
[0034]
The writing timing control by the controller may be automatically performed every time recording is performed on the recording medium, or may be automatically performed when the recording accuracy is lowered to a predetermined value or less. Alternatively, the controller may be operated at the user's discretion when the use environment temperature changes.
[0035]
The magnetic recording apparatus of the present invention may have means for performing heat-assisted recording. The heating means is not particularly limited, but near-field light or an electron beam is preferable. When near-field light or an electron beam is used as a heating means, an extremely small track width can be heated. In particular, near-field light that can directly heat the recording medium and causes little damage to the lubricant present on the surface of the recording medium is most preferable.
[0036]
In the magnetic recording apparatus of the present invention, the medium disk may be rotated like a normal HDD, or the medium may be XY driven. The writing and reading means may have a flat head structure, or may have a structure with a sharp tip like a probe. A plurality of writing and reading means integrated may be used.
[0037]
Next, the magnetic recording apparatus according to an embodiment of the present invention will be described more specifically. FIG. 1 is a sectional view showing the configuration. As shown in FIG. 1, the magnetic recording medium 11 includes a plurality of recording cells 12 separated from each other by a non-recording area (non-magnetic area) 13. A soft magnetic layer 15 is formed below the recording cell with the separation layer 14 interposed therebetween. Above the magnetic recording medium 11, a fixed portion 1 having a single magnetic pole head portion 16a as magnetic recording writing means is disposed. 16b is SiO ₂ The insulating layers 18a and 18b are spiral coils that generate a magnetic field, and 17 is a return path for forming a magnetic circuit. 1b indicates a magnetic flux passing through the magnetic circuit, and 1d indicates a leakage magnetic field.
[0038]
Reference numeral 19 denotes a GMR head unit, which is a magnetic sensor for reading signals. The GMR head unit 19 obtains a signal indicating whether information has been written in the recording cell 12. The GMR head unit 19 is fixed to the fixed unit 1 at a predetermined distance from the single magnetic pole head unit 16a, and is surrounded by the magnetic shield 1a. Reference numeral 1 c denotes the traveling direction of the single magnetic pole head portion 16 a and the GMR head portion 19. The GMR head unit 19 may be located on the right side of the return path 17. As shown in FIG. 1, it is desirable to arrange the single magnetic pole head portion 16a and the GMR head portion 19 close to each other.
[0039]
2 is a detection signal processing means, 3 is a control means, and 4 is a timing controller. The detection signal processing means 2 performs signal processing such as the detected leakage magnetic field, and the control means 3 operates the timing controller 4 so that information can be correctly written based on the obtained signal processing result, and this timing control. The device 4 controls the timing of magnetic field application by the single magnetic pole head portion 16a.
[0040]
Next, the operation of the magnetic recording apparatus having the above configuration will be described. FIG. 2 is an explanatory diagram showing the time change of the output voltage of the GMR head unit 19. Reference numeral 21 denotes a signal from the recording cell 12 having a downward magnetization just below the GMR head unit 19. Reference numeral 22 denotes a signal when a magnetic field is formed between the soft magnetic layer 15 and the return path 17 by applying a downward magnetic field from the single magnetic pole head portion 16a and magnetizing the recording cell 12 directly below. . The GMR head unit 19 is surrounded by a magnetic shield 1a so that signals from other recording cells are not disturbed. However, since the pulse magnetic field from the single pole head unit 16a is very strong, the leakage magnetic field 1d can be detected. It becomes. In this case, since the leakage magnetic field 1d is relatively small, the peak is small. Reference numeral 23 denotes a signal from the recording cell 12 having the upward magnetization just below the GMR head unit 19. Reference numeral 24 denotes a signal when a magnetic field is formed between the soft magnetic layer 15 and the return path 17 by applying an upward magnetic field from the single magnetic pole head portion 16 a and magnetizing the recording cell 12 directly below, thereby forming the magnetic circuit between the soft magnetic layer 15 and the return path 17. . Also in this case, since the leakage magnetic field is small, the peak is small.
[0041]
Reference numeral 25 denotes a signal when a downward magnetic field is applied from the single magnetic pole head 16a but the recording cell is not magnetized downward due to a timing shift. In this case, the magnetic circuit to the soft magnetic layer 15 and the return path 17 is not well formed, and the leakage magnetic field 1d becomes large. Therefore, 25 signal peaks are large. The shape of the signals 22, 24, 25 due to the leakage magnetic field 1d from the single magnetic pole head 16a does not change because the single magnetic pole head 16a and the GMR head unit 19 are moving at the same speed, but the signal 21, from the recording cell, 23 changes depending on the relative speed between the recording cell 12 and the GMR head unit 19. In the case of FIG. 2, the relative speed is relatively small. When the relative speed increases, the peak values of the signals 21 and 23 decrease and it becomes difficult to distinguish, but the shapes of the signals 22, 24 and 25 are almost the same and can be sufficiently detected.
[0042]
When a signal peak such as 25 is detected, a signal for shifting the phase of the magnetic field application timing is generated from the timing controller 4 under the control of the control means 3. The amount of shift may be determined by trial and error, for example, in order to determine whether writing is successful by determining 30 degrees in advance, but the signal peak and magnetic field application from the recording cell 12 when recording is performed in advance. It is preferable to learn the phase shift from the other pulse signal and shift the phase to match the shift. The phase shift between the signal peak from the recording cell and the pulse signal applied with the magnetic field when recording is successful is a value unique to the apparatus.
[0043]
FIG. 3 is an explanatory diagram showing the change over time of the current flowing through the coils 18a and 18b. Reference numeral 31 denotes a signal when recording in the recording cell 12 is successfully performed by applying a downward magnetic field pulse. Reference numeral 32 denotes a signal when recording in the recording cell 12 is successfully performed by applying an upward magnetic field pulse. On the other hand, 33 is a signal when an upward magnetic field pulse is given and recording into the recording cell 12 is not performed successfully.
[0044]
When recording in the recording cell 12 is performed successfully, the current flowing through the coils 18a and 18b is reduced due to the generation of the induction current, and the magnitude of the current signal is reduced. On the other hand, if the recording into the recording cell 12 is not successful, the generation of the induced current is small, the current flowing through the coils 18a and 18b is large, and the magnitude of the current signal is large. As described above, it is possible to determine whether or not the recording with respect to the recording cell 12 has been successfully performed by measuring the current flowing through the coils 18a and 18b.
[0045]
Although FIG. 1 shows a case where recording is performed on one recording cell 12, recording may be performed on two or more recording cells. FIG. 4 is a top view showing this. As shown in FIG. 4A, the centers of the two nearest recording cells 41a located on the recording tracks adjacent to each other are 1 / n periods (n is an integer of 2 or more in FIG. 4) along the track direction. n is 2.) Even if the head 42a (single pole head portion 16a or GMR head portion 19) is arranged obliquely with respect to the recording track direction so as to include the shifted recording cell 41a with respect to the shifted magnetic recording medium. good. Further, as shown in FIG. 4B, a head 42b (single magnetic pole head portion 16a or GMR head portion 19) may be arranged perpendicular to the recording track direction with respect to the recording cell 41b without deviation. Furthermore, as shown in FIG. 4 (c), in the case where three shifted recording tracks are arranged as shown in FIG. 4 (a), the recording cells are inclined with respect to the recording track direction so as to include the shifted recording cells 41c. A head 42c (single pole head portion 16a or GMR head portion 19) may be disposed. In the magnetic recording media shown in FIGS. 4A and 4C, the distance between the recording cells can be increased, and erroneous recording on other recording tracks can be prevented. Such a magnetic recording medium can be easily manufactured using self-assembled molecules. In FIG. 4, one piece of information may be recorded in one recording cell, or one piece of information may be recorded in a plurality of recording cells.
[0046]
The magnetic recording medium according to the present invention can be manufactured, for example, by the following method. That is, as a method for manufacturing a magnetic recording medium of the present invention, a step of forming a continuous or intermittent groove region or a band region containing a specific chemical component corresponding to a recording track band on a substrate, and the groove region Alternatively, it is possible to employ one having a step of forming a two-dimensional regular array structure of self-assembled molecules or fine particles in a band region and a step of forming a recording cell corresponding to the regular array structure.
[0047]
More specifically, when a groove structure having irregularities is used, a regular arrangement along the grooves can be realized by cutting the crystal domains of the self-assembled particles at the step portions of the irregularities.
[0048]
When using a band region patterned with a specific chemical component, select the chemical surface state of the self-assembled particle and the surface state of the chemical component in the band region, so that the self-assembled particle is adsorbed. The part which does not become can be formed. Regular arrangement occurs only in the portion where the self-assembled particles adsorb, and a regular arrangement along the band structure is obtained. In addition, by changing the interaction between the self-assembled particles and the surface according to the chemical pattern, a desired regular arrangement can be obtained only on the chemical pattern where a certain interaction occurs, and the regular arrangement cannot be obtained on another chemical pattern. It is also possible to make a random arrangement or the like. The width of the band structure needs to be sufficiently smaller than the size of the regular arrangement that the self-assembled particles form naturally (that is, when no band structure exists). If these conditions are satisfied, the self-assembled particles can form a structure in which rows are regularly arranged in the width direction of the band structure.
[0049]
As the self-assembled particles, block copolymers or fine particles having a diameter of several to 100 nm made of a polymer, a metal, a semiconductor, an oxide, or the like can be used. When a block copolymer is used, one that can selectively remove one of two or more types of blocks after forming self-assembled particles is used. In this case, it is preferable to use a difference in etching rate with respect to RIE or other etching between blocks.
[0050]
After forming a regular array of self-assembled particles by the method as described above, the recording layer of the base formed beforehand is scraped by ion milling or the like using the self-assembled particles as a mask, and a recording cell in which the desired regular array is formed A row can be formed. In order to scrape the recording layer with a higher aspect ratio, SiO 2 is interposed between the recording layer and the self-assembled particle film. ₂ A film such as Si or Si is formed, and a regular arrangement pattern of self-assembled particles is formed by SiO. ₂ It is also effective to process the recording layer after transfer (pattern transfer) to or Si. SiO ₂ Since Si and Si can be etched with a high aspect ratio by RIE, the recording layer can be etched with a higher aspect ratio by processing using this as a mask.
[0051]
A patterned medium having recording cells embedded in a matrix is produced by coating the regular array of recording cells produced as described above with a matrix material (nonmagnetic material) and flattening the surface by polishing. Can do.
[0052]
A recording cell can also be formed by forming a microhole array regularly arranged in a matrix using self-organized particles as a mask and then filling the holes with a recording material. In this case, a film made of a matrix material is formed on the disk substrate. Next, a resist for forming a groove structure for controlling the arrangement of the self-assembled particles or a band structure patterned with a specific chemical component is formed. A groove structure or a band structure is formed in the resist by lithography. After the self-assembled particles are formed, they are regularly arranged by annealing or the like. Etching is performed using the self-assembled particles as a mask to form holes in the matrix. After removing the resist, a recording material is embedded in the hole. The resist may be removed after embedding the recording material. Alternatively, the resist may be used without being removed.
[0053]
In addition, as the magnetic recording material in the present invention, for example, a high Ku material such as CoPt, SmCo, FePt, or CoPd, or a multilayer film including at least one of them is preferable, and a soft magnetic layer such as NiFe or CoZrNb is used as a base. What has as is preferable. Non-recording materials include non-magnetic metals, diamond-like carbon, SiO ₂ , Al ₂ O _Three Organic polymers are used.
[0054]
It is preferable that the width of the groove region or the band region is such that a recording band (main track) including a plurality of recording tracks (sub-tracks) can be stably produced, seeking is easy, and the recording density is increased. For this purpose, the width of the groove region or band region is preferably 30 nm to 10 μm, more preferably 100 nm to 1 μm.
[0055]
The separation band that separates the groove regions or the band regions may be made of a non-recording material, or may be made of the same recording material as the recording region. When the separation band is made of a non-recording material, the recording band seek is performed by utilizing the fact that an area without a signal (separation band made of a non-recording material) appears periodically every time the read head crosses a plurality of recording bands. Becomes easier. When the separation band is made of the same recording material as the recording cell, the address information of the recording band can be recorded in the separation band.
[0056]
The magnetic recording medium of the present invention can also be manufactured by a method of forming a recording cell by changing a part of the recording layer into a non-volatile reactant by a chemical reaction. With this method, a flat magnetic recording medium can be easily obtained. As the chemical reaction, in the case of a magnetic recording medium such as Co, Fe, or Ni, a halogenation reaction such as a fluorination reaction, oxidation, or nitridation is preferable. The recording characteristic is lost in the portion where the chemical reaction has occurred (nonmagnetic region) and can be clearly distinguished from the recording cell by the reading means.
[0057]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples.
[0058]
Example 1
5A and 5B are a cross-sectional view and a plan view of the magnetic recording medium in this embodiment, respectively. FIG. 5A is a cross-sectional view taken along line AA ′ in FIG.
[0059]
As shown in FIG. 5A, a soft magnetic layer 52 made of CoZrNb is formed on a glass disk substrate 51. A separation layer 53 is formed on the soft magnetic layer 52. Examples of the material of the separation layer 53 include nonmagnetic materials such as Pt and Cr. Further, a large number of magnetic recording cells 54 made of Co are formed on the separation layer 53. The magnetic recording cells 54 are made of SiO. ₂ They are separated from each other by a non-recording area (non-magnetic area) 55 made of A carbon protective film 56 is formed on the magnetic recording cell 54 and the non-recording area 55.
[0060]
On the other hand, as shown in FIG. 5B, a non-recording material (non-magnetic material, SiO) is formed on the surface of the magnetic recording medium. ₂ etc. ), And a recording track band 58 is formed between the separation bands 57. The recording track band (main track) 58 includes a plurality of recording tracks (sub-tracks) in which the recording cells 54 are periodically arranged in the recording track direction. As shown in this figure, the centers of the two closest recording cells located on the recording tracks adjacent to each other are shifted by a half period along the track direction. The diameter of the recording cell is 30 nm, and the interval between the recording cell and the recording cell is 10 nm.
[0061]
FIG. 6 is an explanatory diagram schematically showing a magnetic recording apparatus according to the present embodiment. The magnetic disk 61 manufactured as described above is mounted on a spindle motor 65 to rotate. A slider head 64 is disposed on the magnetic disk 61, and a single magnetic pole write head 62 as a magnetic field applying means and a read magnetic sensor (planar type GMR element) 63 are integrally mounted. FIG. 6 is a drawing in which the direction connecting the single magnetic pole write head 62 of the slider head 64 and the GMR element 63 coincides with the radial direction of the magnetic disk 61 for the sake of convenience. The slider head 64 is arranged so that the direction connecting the single magnetic pole write head 62 and the GMR element 63 is the direction along the recording track direction (the vertical direction in FIG. 6).
[0062]
On the medium facing surface of the slider head 64, a single magnetic pole write head 62 having a length of 30 nm and a width of 30 nm and a GMR element 63 having a length of 30 nm and a width of 30 nm are formed. The GMR element 63 and the single pole write head 62 are separated by 200 nm. The configurations of the GMR element 63 and the single pole write head 62 are the same as those shown in FIG.
[0063]
The slider head 64 is positioned by a two-stage actuator (not shown) having a piezoelectric element as a component. The control means 3 controls the magnetic field strength, the application timing thereof, and the relative speed between the magnetic disk 61 and the slider head 64.
[0064]
FIG. 7 is a perspective view showing the internal structure of the magnetic recording apparatus of this embodiment. The magnetic disk 71 is mounted on a spindle motor 72 and is rotated by a control signal from a control unit (not shown). An actuator arm 74 is held on the shaft 73, and the actuator arm 74 supports a suspension 75 and a slider head 76 at the tip thereof. When the magnetic disk 71 rotates, the medium facing surface of the slider head 76 is held in a state where it floats a predetermined amount from the surface of the magnetic disk 71, and information is recorded and reproduced. A voice coil motor 77 is provided at the base end of the actuator arm 74, and the actuator arm 74 can be rotated by the voice coil motor 77. A piezo element 78 for fine position control is installed at the tip of the actuator arm 74. Control means (microprocessor) for controlling the timing of writing (recording) by the magnetic field application recording means is installed on a printed board inside the magnetic recording apparatus.
[0065]
In this embodiment, a write signal is detected by using a magnetic sensor (planar type GMR element) 63, and a controller (control means) learns by trying to write and read in advance, so that each recording cell has one. It was possible to write an arbitrary signal. Also, there are 10 write mistakes ^-Five I was able to:
[0066]
(Example 2)
FIGS. 8A and 8B are a cross-sectional view and a plan view, respectively, of the magnetic card medium in this embodiment. FIG. 8A is a cross-sectional view taken along line BB ′ in FIG.
[0067]
As shown in FIG. 8A, a separation layer 82 made of a nonmagnetic material such as Pt or Cr is formed on a glass substrate 81. A large number of magnetic recording cells 83 made of FePt fine particles are formed on the separation layer 82, and the magnetic recording cells 83 are separated from each other by a non-recording region (nonmagnetic region) 84 made of carbon. A carbon protective film 85 is formed on the magnetic recording cell 83 and the non-recording area 84.
[0068]
As shown in FIG. 8B, a non-recording material (non-magnetic material, SiO) is formed on the surface of the magnetic card medium. ₂ . ) And a recording track band 87 separated by the separation band 86 is formed in parallel. The recording track band 87 includes a plurality of recording tracks (subtracks) in which recording cells 83 are periodically arranged in the track direction. The diameter of the recording cell is 10 nm, and the interval between the recording cell and the recording cell is 3 nm.
[0069]
FIG. 9 is an explanatory diagram schematically showing a magnetic recording apparatus according to the present embodiment. A multi-head 94 is disposed on the magnetic card medium 91, and a single magnetic pole write probe 92 as a magnetic field applying means and a coil 93 for writing and reading are integrally mounted. A multi-auxiliary magnetic pole 95 forms a magnetic circuit with the single magnetic pole writing probe 92.
[0070]
On the medium facing surface of the multi-head 94, 20 × 20 single-pole writing probes 92 having a tip length of 10 nm are formed at an interval of 5 mm. 20 × 20 multi auxiliary magnetic poles 95 are formed corresponding to the multi head 94. The surface area of the multi auxiliary magnetic pole is 5 × 5 mm. The multi-head 94 and the multi-auxiliary magnetic pole 95 are controlled independently.
[0071]
The multihead 94 is positioned by an XYZ actuator 96. The magnetic field strength, the application timing thereof, and the relative speed between the card medium 91 and the multi-head 94 are controlled by the control means 3 shown in FIG.
[0072]
In this embodiment, as described with reference to FIG. 3, the current signal at the time of writing is detected using the coil 93, and the controller (control means) is made to learn by trying writing and reading in advance, thereby recording one recording cell. Arbitrary signals could be written each time. Also, there are 10 write mistakes ^-Five I was able to:
[0073]
In addition, this invention is not limited to the said embodiment. For example, the size of the self-assembled particles is preferably 3 to 100 nm, more preferably 10 to 50 nm as a diameter. The shape of the self-assembled particles is preferably a circle, an ellipse, a rectangle, or a square corresponding to the shape of the recording cell described above, and a circle that can be easily formed by self-assembly is particularly preferable.
[0074]
Further, when the recording density of Tbpsi is to be realized by the magnetic recording medium of the present invention, the width of the groove structure or the band structure is determined as follows. For example, when two recording cell rows exist in one recording track band, the width of the groove structure or the band structure is about 40 nm. This is a size that can be produced by ordinary electron beam lithography. Actually, since more than two sub-tracks can be formed in one recording track band, it is possible to use a lithography means having a low resolution but a low cost and a high throughput. As lithography, a method using a scanning probe such as photolithography, electron beam lithography, atomic force microscope, scanning tunneling microscope, and near-field light microscope, nanoimprint lithography (PR Krauss, et al., J. Vac). Sci.Technol.B13 (1995), pp. 2850) can be used.
[0075]
In the above embodiment, when preparing a magnetic recording medium by self-organization, various block copolymers can be used. For example, when a block copolymer made of polystyrene and polybutadiene is used, a polystyrene block is obtained by ozone treatment. Development processing is possible so as to leave only. In the block copolymer consisting of polystyrene and polymethyl methacrylate, polystyrene is more CF than polymethyl methacrylate. _Four Etching resistance against reactive ion etching (RIE) using as an etchant is high. For this reason, it is possible to selectively remove only polymethylmethacrylate and the recording layer therebelow by RIE (K. Asakawa et al .; APS March Meeting, 2000).
[0076]
Examples of such block copolymers include polybutadiene-polydimethylsiloxane, polybutadiene-4-vinylpyridine, polybutadiene-methyl methacrylate, polybutadiene-poly-t-butyl methacrylate, polybutadiene-t-butyl acrylate, poly-t-butyl methacrylate-poly. -4-vinylpyridine, polyethylene-polymethylmethacrylate, poly-t-butylmethacrylate-poly-2-vinylpyridine, polyethylene-poly-2-vinylpyridine, polyethylene-poly-4-vinylpyridine, polyisoprene-poly-2- Vinylpyridine, polymethyl methacrylate-polystyrene, poly-t-butyl methacrylate-polystyrene, polymethyl acrylate-polystyrene, polybutadiene-poly Tylene, polyisoprene-polystyrene, polystyrene-poly-2-vinylpyridine, polystyrene-poly-4-vinylpyridine, polystyrene-polydimethylsiloxane, polystyrene-poly-N, N-dimethylacrylamide, polybutadiene-sodium polyacrylate, polybutadiene -Polyethylene oxide, poly-t-butyl methacrylate-polyethylene oxide, polystyrene-polyacrylic acid, polystyrene-polymethacrylic acid, etc. These are examples of AB type diblock polymers, but may be ABA type triblock copolymers.
[0077]
When a block copolymer is used, it is preferable to use molecules having a component ratio that forms a micelle structure or a cylinder structure on the substrate surface. This makes it possible to form circular recording cells that are separated from each other and regularly arranged. A block copolymer dissolved in an appropriate solvent such as toluene can be formed by spin coating or the like. Phase separation of the block copolymer into a self-organized arrangement is generally obtained by annealing at a temperature above the glass transition temperature of the material.
[0078]
In addition, in order to produce a magnetic recording medium, fine particles having a diameter of several tens of nanometers made of polymer or metal can be used. In this case, the solution in which the fine particles are dispersed is spread on the disk having the band structure and dried to remove the solvent, and then the self-adsorbed fine particles are removed by using an appropriate solvent. A systematic regular array can be formed. It is also possible to place the disk substrate in a solution in which the fine particles are dispersed for a certain period of time so that the fine particles are adsorbed on the disk substrate and be regularly arranged.
[0079]
In addition, various modifications can be made without departing from the spirit of the present invention.
[0080]
【The invention's effect】
According to the present invention, it is possible to provide a magnetic recording apparatus and a magnetic recording method which can be densified and have few writing errors.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram illustrating a magnetic recording apparatus according to an embodiment of the invention.
FIG. 2 is an explanatory diagram showing a time change of an output voltage of the GMR head in one embodiment of the present invention.
FIG. 3 is an explanatory diagram showing a change over time of a write coil current according to an embodiment of the present invention.
FIG. 4 is a plan view showing a case where writing is performed on two or more recording cells according to the present invention.
FIGS. 5A and 5B are a cross-sectional view and a plan view of a magnetic recording medium in Example 1 according to the present invention. FIGS.
FIG. 6 is a cross-sectional view showing a magnetic recording apparatus in Example 1 according to the present invention.
FIG. 7 is a perspective view showing the inside of the magnetic recording apparatus according to the first embodiment of the invention.
FIG. 8 is a cross-sectional view and a plan view of a magnetic card medium according to a second embodiment of the present invention.
FIG. 9 is a sectional view showing a magnetic recording apparatus in Example 2 according to the present invention.
[Explanation of symbols]
1 ... Fixing part
1a ... Magnetic shield
1b: Magnetic flux passing through the magnetic circuit
1c: Head traveling direction
1d ... Magnetic field leakage
2 ... Detection signal processing means
3. Control means
4. Timing controller
11. Recording medium
12 ... Recording cell
13: Non-recording area
14 ... Separation layer
15 ... Soft magnetic layer
16a: Single pole head
16b ... SiO ₂ Insulating layer consisting of etc.
17 ... Return path
18a, 18b ... coil
19 ... GMR head
1d ... Magnetic field leakage
21: Signal from a recording cell having a downward magnetization just below the GMR head
22: A signal when a magnetic field is formed between the soft magnetic layer 15 and the return path 17 by applying a downward magnetic field from the single magnetic pole 16 and magnetizing the recording cell immediately below, downward.
23: Signal from a recording cell having an upward magnetization just below the GMR head
24: Signal when a magnetic field is formed between the soft magnetic layer 15 and the return path 17 by applying an upward magnetic field from the single magnetic pole 16 and magnetizing the recording cell immediately below,
25: Signal when a downward magnetic field is applied from the single magnetic pole 16 but the timing is shifted and the recording cell is not magnetized downward
31: Signal when writing to a recording cell is performed successfully by applying a downward magnetic field pulse
32: Signal when writing to a recording cell is successfully performed by applying an upward magnetic field pulse
33: Signal when writing to a recording cell is not performed successfully by applying an upward magnetic field pulse
41a, 41b, 41c ... recording cells
42a, 42b, 42c ... writing head
51 ... Glass disk substrate
52. Soft magnetic layer
53 ... Separation layer
54 ... Recording cell
55. Non-recording area
56 ... Protective film
57 ... Separation zone
58 ... Recording track belt
61 ... Magnetic disk
62 ... Single-pole writing head
63 ... Magnetic sensor (GMR element)
64 ... slider head
65 ... Spindle motor
71 ... Magnetic disk
72 ... Spindle motor
73 ... axis
74 ... Actuator arm
75 ... Suspension
76 ... Slider head
77 ... Voice coil motor
78 ... Piezo element
81 ... Glass substrate
82. Separation layer
83 ... Recording cell
84: Non-recording area
85 ... Protective film
86 ... Separation zone
87 ... Recording track belt
91 ... Magnetic card medium
92 ... Single pole writing probe
93 ... Coil
94 ... Multihead
95 ... Multi auxiliary magnetic pole
96 ... Actuator

Claims (8)

  A magnetic recording medium having a plurality of recording cells periodically arranged along the recording track direction and a non-magnetic region separating the recording cells, and applying a magnetic field to the magnetic recording medium, information is recorded in the recording cells. A magnetic field application recording means for recording, a detection means for detecting a leakage magnetic field generated by applying a magnetic field of the magnetic field application recording means, and a control means for controlling a recording timing by the magnetic field application recording means based on the detection of the leakage magnetic field; A magnetic recording apparatus comprising: In the magnetic recording medium, the centers of the two nearest recording cells located on recording tracks adjacent to each other are shifted by 1 / n period (n is an integer of 2 or more) along the recording track direction. The magnetic recording apparatus according to claim 1, wherein: 3. The magnetic recording medium according to claim 2, wherein the centers of the two nearest recording cells located on the recording tracks adjacent to each other are shifted by a half period along the recording track direction. Magnetic recording device. 4. The magnetic recording apparatus according to claim 1, wherein the recording cell is composed of a perpendicular magnetic recording layer, and the magnetic recording medium has a soft magnetic layer under the recording cell. The magnetic recording apparatus according to claim 1, wherein the magnetic field application recording unit includes a single magnetic pole head. 6. The magnetic recording apparatus according to claim 1, wherein the detection unit also detects and reads information recorded in a recording cell of the magnetic recording medium. A method of performing magnetic recording on a magnetic recording medium having a plurality of recording cells periodically arranged along the recording track direction and a nonmagnetic region separating the recording cells, and applying a magnetic field to the magnetic recording medium Applying and recording information in the recording cell, detecting a leakage magnetic field generated by applying a magnetic field of the magnetic field application recording means, and detecting the leakage magnetic field
And controlling the recording timing by the magnetic field application recording means. A method of performing magnetic recording on a magnetic recording medium having a plurality of recording cells periodically arranged along the recording track direction and a non-magnetic region separating the recording cells. To record information in the recording cell, detect a current change in the magnetic field application recording means caused by application of the current magnetic field of the magnetic field application recording means, and based on the detection of the current change, by the magnetic field application recording means A magnetic recording method comprising controlling recording timing.

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