JP2001110001A - Magnetic recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recorder using a medium regularly arranging isolated magnetic minute particles and precisely controlling a recording position not only in the track direction but also in the bit direction since a recordable part is discrete. SOLUTION: The positions of respective magnetic minute particles are decided with a magnetic sensor for performing the recording to the magnetic minute particles, and a recording head or a laser irradiation position is position- controlled based on that information.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a recording apparatus using a recording medium having isolated magnetic fine particles.

[0002]

2. Description of the Related Art Conventionally, as a magnetic recording medium, a magnetic continuous film sputter-deposited on a substrate has been used. Recording is performed on the magnetic continuous film by irradiation with a magnetic head or a laser beam. In the case of a magnetic head, the magnetic field
In the case of laser light, high densification has been achieved by reducing the regions where the temperature rises upon irradiation.

In a conventional magnetic recording medium, the magnetic material is continuous and there is no restriction on the recording position. As for the recording method, for example, I Triple E Transaction on Magnetics, Vol. 35 (199)
9 years) pp. 695 to 699 (IEEE Trans. Magn. 35)
(1999) pp. 695-699), a method of shaving a magnetic head with a focused ion beam to localize a magnetic field is known.
In this method, it is considered that the size of the recording bit can be limited by the processing size of the head.

[0004] For example, Japanese Patent Application Laid-Open No. 51-107121 discloses a method of performing writing by applying an external magnetic field simultaneously with light irradiation. Further, Japanese Patent Application Laid-Open No. H8-249751 proposes a method of performing recording by relatively moving the position of a medium and light for heating. In this method, it is possible to record a recording mark smaller than the diameter of the light by synchronizing the movement of the light spot and the period of the application of the magnetic field.

However, as the density increases, the volume of the magnetic material per bit decreases, and generally, problems such as a reduction in the ratio of signal to noise and a phenomenon of resistance to thermal fluctuation occur.
It has been pointed out that it is difficult to further increase the density of the conventional magnetic continuous film. to solve this problem,
In a magnetic recording medium, a recording method for achieving high-density recording by periodically arranging magnetic fine particles and recording one bit per particle is described in, for example, Journal of Applied Physics 76 (1994), p. 6673. 6675 (J. Appl. Phys. 76 (1994) pp6673-6675)
And Japanese Patent Laid-Open No. Hei 10-233015. Such a medium is considered to be effective for high-density recording because the thermal stability of recording bits is high and noise can be reduced by adjusting the size, shape, and magnetic characteristics of each magnetic fine particle.

However, in such a medium in which magnetic fine particles are arranged, it is known that the dispersion of the switching magnetic field of each fine particle exists, for example, from Journal of Applied Physics 85 (1999) pp. 8327 to 8331.
Page (J. Appl. Phys. 85 (1999) pp. 8327-8331).

[0007]

In the conventional recording on a continuous film, it was possible to record at an arbitrary position on the continuous film. Therefore, it was not necessary to strictly control the recording position. When recording is performed on magnetic particles that are arranged in isolation, magnetic information cannot be written in the non-magnetic portion between the magnetic particles, so the position of the particles must be accurately aligned with the recording position. is there.

In a recording system in which light and a magnetic field are superimposed and heated, the recording density and the recording speed must be such that when writing to adjacent bits, the previously recorded bits must be sufficiently cooled. Has limited the recording speed.

SUMMARY OF THE INVENTION The present invention provides a recording method for recording information on a target fine magnetic particle on a magnetic recording medium having an arrangement of magnetic fine particles and not affecting other bits. And a recording device using the same.

[0010]

In order to achieve the above object, the position of fine particles is detected by using a magnetic sensor having a fixed position relative to a recording head, and recording is performed on the fine particles based on the information. Perform According to the above configuration, it is possible to select a bit to be recorded and to perform magnetization reversal. Further, when recording is performed on a recording medium in which fine particles are regularly arranged as described above, it is possible to perform recording on one particle by superimposing and applying light and magnetism.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIGS. 1A and 1B show an example of a magnetic recording apparatus for realizing a recording system according to the present invention. FIG. 1A is a plan view schematically showing a magnetic recording apparatus, and FIG. 2B is a cross-sectional view showing a recording unit and a part of a recording medium in an enlarged manner.

The recording medium 100 is driven to rotate by a motor (not shown), and a GMR head 106 for reading signals and a recording head 107 for generating a recording magnetic field are arranged facing the recording surface of the recording medium 100. These heads are held at the distal end of an arm 105, and the arm 105 is controlled by a moving mechanism 110 so that the distal end can move in a required range of the recording medium 100.
Therefore, the GMR head 106 and the recording head 10
The relative position of 7 is fixed, and its separation distance is measured in advance.

A recording medium 100 has a diameter 30 having a perpendicular anisotropy due to crystal anisotropy on a substrate 101, for example.
The magnetic fine particles 102 having a columnar shape of nm are regularly arranged, and the space between the magnetic fine particles is filled with a non-magnetic material 103. The distance between the centers of the magnetic fine particles 102 is slightly different depending on the track, but is approximately 50 nm. The distance between the centers of the tracks is also approximately 50 nm. Thus, the particle density corresponds to about 250 gigabits per square inch. Also,
In addition to the magnetic fine particles for recording the information arbitrarily required by the user, a magnetic material for tracking is arranged, and the tracking is performed based on a signal from the magnetic material. Of course, in the present invention, it goes without saying that the perpendicular anisotropy of the magnetic fine particles of the recording medium is not limited to the perpendicular anisotropy caused by the crystal anisotropy, but can be applied to any case of the perpendicular anisotropy.

The surface of the recording medium 100 is covered with a protective film 104. This recording medium has a disk shape, rotates at 10,000 rpm about the center of the disk as a rotation axis, and can move relatively to the recording head 107 and the like. The recording head 107 is attached to a slider, and is controlled so that the distance from the recording medium surface is constant.

To record information, first, the GMR head 106
Is sent to the magnetic particle position detecting device 108 based on the signal from As will be apparent from the following description, in the recording medium to which the present invention is applied, the magnetic fine particles 10
2 are independent, each magnetic particle 102 always has a signal corresponding to “1” or “0”. When the recording medium is initialized, all the magnetic fine particles 102 are "1" or "0". Therefore, no matter where the GMR head 106 is located, the GMR head 106 is set to “1” or “0” at the position corresponding to the magnetic fine particles 102.
Can be detected. When receiving the signal from the GMR head 106, the magnetic fine particle position detecting device 108 determines the recording head 107 and the magnetic fine particle 102 based on the relationship between the relative distance between the GMR head 106 and the recording head 107 and the size of the magnetic fine particle 102. However, it is possible to know the timing of coming to the next opposing position. A write timing signal is sent to the magnetic coil driving device 109 in accordance with this timing, and recording is performed on the magnetic fine particles 102 from the recording head 107. At this time, the magnetic fine particle position detecting device 108 preferably reads signals from the plurality of magnetic fine particles 102, performs a maximum likelihood decoding process, and considers a variation in the arrangement of the magnetic fine particles 102.

Since the distance between the magnetic fine particles 102 and the linear velocity of the recording head 107 may be different for each track of the recording medium, the magnetic fine particle position detecting device 108 uses the track number and the track By referring to the distance between the magnetic fine particles 102, the center of the magnetic fine particles can always be detected.

A write timing signal from the magnetic fine particle position detecting device 108 is transmitted to the magnetic coil driving device 109, and when the recording head 107 comes to the position of the magnetic fine particle 102 to be recorded, the magnetic coil driving device 10
9, the output is adjusted and a necessary external magnetic field is applied. At this time, the recording head 107
The application of the magnetic field may be started as early as possible without affecting the other recording bits so as to generate the maximum magnetic field when passing through the center of FIG. This can be easily realized by how to generate a write timing signal corresponding to the detection of the magnetic fine particles 102. This makes it possible to accurately record on the target magnetic fine particles 102. It should be noted that information is reproduced by GMR in the same manner as a conventional recording device.
This is performed by detecting the magnetization direction of the magnetic fine particles 102 using the head 106.

In this embodiment, instead of the GMR head 106, another magnetic sensor having the required sensitivity and resolution may be used. Further, the relative movement between the recording medium 100 and the GMR head 106 does not depend on the rotation of the disk, but may use a translation mechanism using a piezo element or a linear motor. In this embodiment, the same head is used for signal reproduction and position detection, but different heads may be used. In this case, it is necessary to know the relative position between the recording head 107 and the position detection head.

FIG. 2 schematically shows a difference between a signal from a recording medium to which the present invention is applied and a signal from a conventional magnetic continuous film. FIG. 2A schematically shows a cross-sectional view of a medium in which the magnetic fine particles 102 are arranged inside the non-magnetic substance 103, and the thick arrows indicate the magnetization directions of the fine particles. FIG.
(B) shows a signal when the information of the medium is detected by the GMR head. The signal reaches a peak at a portion corresponding to the center of each magnetic fine particle. It can also be seen that independent signals are generated when the magnetization of the adjacent magnetic fine particles is in the same direction or in the opposite direction. If the resolution of the GMR head is not sufficiently high, the position and height of the peak may be slightly different from this figure. However, as described above, an accurate bit position is determined by the maximum likelihood decoding process and distance information between recording bits. It is possible to decide. FIG. 2C is a schematic diagram when similar information is recorded on the magnetic continuous film 204. In this case, the bits are not independent, so
Although there is no partition as shown in the figure, a bit partition line is shown in the sense that there is information for each bit. Thick arrows indicate the magnetization direction of the fine particles. FIG. 2 (d)
Indicates a signal extracted when information recorded on the magnetic continuous film 204 is reproduced by the GMR head. When the magnetization of the adjacent bits is in the opposite direction, a peak occurs at the center of the recording bit, but when the magnetization of the adjacent bits has the same direction, no change occurs in the signal. Therefore, the center position of the bit cannot be determined from the signal waveform itself.

Embodiment 2 In Embodiment 1, the GMR head 106 and the recording head 1
Although the positional relationship information of 07 is measured in advance, in this embodiment, the relative positional relationship does not have to be measured in advance. FIG. 3 shows a disk 10 to which this embodiment can be applied.
It is a schematic diagram which shows the top view of 0. Magnetic disk 100
Is composed of a recording region 301 in which magnetic fine particles are arranged, a magnetic continuous film region 302 that is not patterned in a portion other than the recording region 301, and a bump 303. This embodiment is characterized in that a magnetic continuous film area 302 is prepared in addition to the original recording area 301.

Before using the magnetic recording apparatus, the magnetic continuous film 30
2, a specific recording pattern is written using the recording head 107. After that, the written recording pattern is detected by the GMR head 106. Here, the recording pattern is desirably a simple pattern in which the direction of magnetization is alternately changed to upper, lower, upper, lower, and upper so that a peak shift does not occur due to superposition of a signal. The interval between the recording head 107 and the GMR head 106 can be obtained from the time of a series of processing from writing to reading and the moving speed of the disk 100. After this interval is obtained, recording on the fine particles in the recording area 301 can be performed as in the first embodiment.

Incidentally, the magnetic continuous film region 302 is not necessarily required to be at the outermost periphery of the disk. Further, the continuous portion does not need to extend over one round, but only needs to have a length necessary to know the distance between the recording head and the position detection head. Example 1
In this example, the GMR head 106 was fixed in front of the recording head 107.
May be arranged before the.

Example 3 In Example 1, recording was performed by arranging fine particles having perpendicular anisotropy caused by crystal anisotropy on the recording medium 100. The present invention can also be applied to a case where recording is performed using a recording medium 100 in which fine particles having in-plane anisotropy are arranged instead of fine particles having in-plane anisotropy. This embodiment is shown in FIG.

FIG. 4A is a schematic diagram showing a part of an array of fine particles 401 having in-plane anisotropy when the recording medium 100 is viewed from above, and the bold arrows inside indicate the magnetization. Indicates the direction. FIG. 4B shows the bit sequence as a GMR head 1
06 is a signal when reproduced. Magnetic fine particles 401 having in-plane anisotropy are periodically arranged on a substrate,
A and B are the width of the magnetic fine particles 401 themselves and the interval between the adjacent magnetic fine particles 401, and are arranged so that A ≠ B.

For an in-plane medium, the GMR head 106
Is generated at the beginning and end of the bit, so that the detection of the magnetic fine particles 401 cannot be determined only by detecting the peak position, and the center position of the bit is not determined. However, a signal of a different sign is always obtained at the beginning and end of the bit. Therefore, when the time C when the signals having different signs of the obtained signals are combined and the width A of the magnetic fine particles 401 correspond to each other, it is assumed that the magnetic fine particles 401 are detected, and the center of the time C is set to the magnetic field. By using the center of the fine particles, the magnetic fine particles 102 of the first embodiment can be handled in the same manner as the detected fine particles.
The interval B between the magnetic fine particles 401 and the time D between signals correspond to each other.

If the magnetic fine particles 401 can be detected, recording can be performed at the bit center position even in the aligned fine particles having in-plane anisotropy, as in the first embodiment.

Embodiment 4 FIGS. 5 (a) and 5 (b) show the same as FIGS. 1 (a) and 1 (b).
Another embodiment of the magnetic recording apparatus of the present invention is shown. FIG. 1A is a plan view schematically showing a magnetic recording apparatus, and FIG. 2B is a cross-sectional view showing a recording unit and a part of a recording medium in an enlarged manner.

In the first embodiment, the recording head 107 and G
In order to know the interval between the MR heads 106, the recording head 107 is disposed on the front side with respect to the traveling direction of the recording medium. On the other hand, in this embodiment, the GMR head 106 is disposed on the front side in the traveling direction of the recording medium 100. As in the first embodiment, cylindrical magnetic fine particles 102 are arranged on a substrate 101 of a recording medium 100, and a non-magnetic material 10
Filled with three. The medium surface is protected by a protective film 104. GMR head 106 and recording head 107
Is fixed to the arm 105 and can move relative to the recording medium 100. In this embodiment, the recording medium 10
Since it is necessary to know the axis position corresponding to the rotation of 0, an encoder 501 is attached to the rotation axis of the drive motor of the recording medium 100. Also, the bit position detecting device 1
08 is provided with a correction signal input terminal 502 for apparently correcting the detection of the bit position, as described later.

FIG. 6A is a diagram showing a detection signal of the GMR head 106. The horizontal axis represents time, and the vertical axis represents signal magnitude. FIG. 6B shows a state in which the GMR head 106 detects the magnetic fine particles 102 from the axial position (time point) where the magnetic fine particles 102 are detected.
Shows the deviation Δθ of the axis position (time) until the magnetization reversal is performed, the horizontal axis represents time, and the vertical axis represents the magnitude of the deviation of the axis position (time).

In order to know the distance between the recording head 107 and the GMR head 106, the entire medium is magnetized in one direction in advance. First, with respect to this medium, at the axial position (time point) at which the GMR head 106 detected the magnetic fine particles 102, 1
The magnetization reversal of the magnetic fine particles 102 is performed by the recording head 107 over several bits on one track. in this case,
As a matter of course, a pulse-like magnetization reversal signal corresponding to the interval between the magnetic fine particles 102 is given. After providing the magnetization reversal signal, when it is detected from the signal of the encoder 501 of the rotation axis of the drive motor that the disk has returned to the axis position where recording has been performed by making one rotation, the GMR head 106 is used. The recording state of the magnetization reversal signal is measured. Recording head 1
When the signal of the magnetization reversal by 07 does not completely match the position of the magnetic fine particles 102, it means that the recording magnetic field has been applied on the non-magnetic material 103, and the magnetization state does not change from the initial magnetization state. Signal period shown in T ₁ of the FIGS. 6 (a) is assumed to correspond thereto.

Next, by giving a signal of a predetermined magnitude to the slightly shifted position on the same track of the disk, that is, the correction signal input terminal 502, the signal of the encoder 501 is apparently corrected, and At the slightly shifted upper position, the GMR head 106 detects the magnetic fine particles 102, and the magnetization of the magnetic fine particles 102 is inverted.

When this operation is repeated while the magnitude of the signal applied to the correction signal input terminal 502 is changed little by little, the magnetization reversal by the GMR head 106 causes
There is a time when it is performed at the 02 position. T in FIG. 6 (a)
It is assumed that the signal in the period shown in ₂ corresponds to this. At this time, the magnitude of the signal applied to the correction signal input terminal 502 is Δθ ₂ . When this operation is further repeated, FIG.
As the period of the signal shown in T ₃ of (a), the same signals being manifested as the first state. At this time, the correction signal input terminal 50
2 is Δθ ₃ . If this operation is continued while increasing the correction signal, the GMR
The magnetization reversal by the head 106 is repeated, and FIG.
The signal shown in FIG.

In FIG. 6, the description starts from a state where no magnetization reversal occurs at first, but this does not matter if any state appears first. In any case, if the signal supplied to the correction signal input terminal 502 is shifted little by little, a point in time when the signal returns to the initial state always appears.

When the deviation Δθ of the axial position (time) required for the magnetization reversal of the magnetic fine particles 102 is known in this way, the recording head 107 and the GMR are determined from the linear velocity of the recording unit at this time.
The distance of the head 106 can be known. In the present embodiment, the portion of the continuous magnetic film shown in the second embodiment becomes unnecessary,
Further, since the recording can be performed by the recording head 107 immediately after the position is detected by the GMR head 106, an improvement in the positional accuracy can be expected. In the above description, recording, signal reproduction, position detection, and fine adjustment are repeatedly performed for each round of the disk. However, while changing the signal to be applied to the correction signal input terminal 502 little by little for each portion within one round, The recording may be repeatedly performed, and thereafter, the reproduction and the position detection by the GMR head may be collectively performed. In this way, the recording head 10
It is possible to shorten the detection time of the distance between the GMR head 7 and the GMR head 106.

FIG. 7 is a schematic view of the recording medium 100 as viewed from above. As shown in the figure, the recording medium 100 includes magnetic fine particles 102 arranged on a substrate and a portion 603 having tracking information. Although the recording medium 100 is concentrically divided into a plurality of recording zones, two recording zones 604 and 605 are shown in the figure for simplicity. Compared with the recording zone 605 near the inner periphery of the disk, the number of magnetic particles per round is larger in the recording zone 604 near the outer periphery. Thereby, a substantially uniform linear recording density can be achieved over the entire area of the disk. Accordingly, the number of magnetic portions 603 that carry tracking information is increased in the recording zone on the outer peripheral side. Incidentally, reference numeral 606 denotes a bump of the disk.

In the fourth embodiment, the encoder 501 described above can be omitted by focusing on the magnetic portion 603 that carries tracking information. That is, a different number is assigned to the magnetic portion 603 that carries the tracking information for each track and sector, and the position on the disk can be determined by detecting the information with the GMR. Therefore, the position information on the disk obtained by the encoder 501 can be replaced by a signal obtained from the magnetic portion 603 that carries tracking information.

Embodiment 5 FIG. 8 shows another embodiment of the magnetic recording apparatus of the present invention. This embodiment includes a GMR head 106 for reading a signal,
The configuration relating to the magnetic head 107 for generating a magnetic field, the arm 105 for holding these, and the recording medium 100 can be applied to the above-described embodiments. In addition,
In this embodiment, as will be described later, near-field light irradiation is performed to control the temperature of the magnetic fine particles 102, so that the substrate 101 and the nonmagnetic material 103 are optically transparent substances such as glass. good. In the present embodiment, in addition to the above, the laser beam source 707 for heating the recording bit (the magnetic fine particles 102), a collimating lens 710, and an optical fiber 708 for guiding light are provided. The tip of the optical fiber is coated with a metal coating, and near-field light oozes out from an opening opened in the center of the coating. The irradiation position of the irradiation light 709 is adjusted so as to be directly below the magnetic head 107. Further, as in the previous embodiment, the relative positions of the GMR head 106 and the magnetic head 107 are fixed, and the distance is measured in advance.

In this embodiment, the reproduction of information is performed by using the GMR head 106 as in the conventional recording apparatus.
02 is detected by detecting the magnetization direction. When writing the information, when the irradiation position of the irradiation light 709 comes directly below the magnetic fine particles 102 to be written, the output is adjusted by the laser driving device 712 to irradiate the irradiation light 709, so that the writing is necessary. The temperature of the magnetic body is raised to the temperature, and at the same time, the magnetic head 107 is moved by the magnetic coil driving device 109.
And apply the required external magnetic field. The magnetic fine particles 10 are set so that the magnetization of the recorded bit reaches saturation.
An external magnetic field is applied from the time when the temperature of Step 2 is sufficiently high to a temperature at which the magnetization direction is not easily inverted. Writing of one recording bit is completed, and writing of the next bit is performed while the temperature is sufficiently cooled. Note that since the substrate 101 and the nonmagnetic material 103 are made of an optically transparent material such as glass, the irradiation light is transmitted therethrough, and the temperature rise by laser light irradiation is smaller than that of the magnetic fine particles 102. In addition, the non-magnetic material 10
No. 3 has a lower thermal conductivity than the magnetic fine particles 102, so that only the irradiated fine particles are more likely to be selectively heated and the heat is hardly transmitted to the other magnetic fine particles 102 as compared with the conventional recording on a continuous film. Therefore, high-speed recording can be performed as compared with the case where recording is performed by superimposing light and a magnetic field on a continuous film as in JP-A-10-233015. In general, the substrate 10
By using a material having a higher thermal conductivity than the non-magnetic material 103 as 1, cooling after recording is rapidly performed, and higher-speed recording becomes possible. Instead of an optical fiber, a solid immersion lens (for example, Applied Physics Letters 68 (1996), pp. 141-143 (Appl. Phys. Lett. 68 (1996) pp. 141-143)) or a belly small aperture laser (for example, Applied
Physics Letters 75 (1999) pp. 1515 to 1517 (Appl. Phys. Lett. 75 (1999) pp. 1515-1)
Other light sources capable of local heating, such as 517)), may be used.

Embodiment 6 In the embodiment shown in FIG. 8, even when the spot diameter of the irradiation light 709 is larger than the period of the arrangement of the magnetic fine particles 102, the period of the magnetic field application and the moving speed are adjusted to adjust the moving speed. As shown in (1), recording can be performed at a cycle equal to or less than the spot diameter. FIG. 9 (a)-
(C) shows the magnetic fine particles 1 obtained when such recording is performed.
FIG. 2 is a schematic diagram showing a state of magnetization of No. 02. Reference numeral 802 denotes the size of the spot of the irradiation light 709. In the figure, the irradiation light 7
An example in which three magnetic fine particles 102 are covered by the spot 09 is shown. Black portions indicate downward magnetization, and white portions indicate upward magnetization.

In FIG. 9A, the magnetic fine particles 102 are all downward and have the same magnetization direction. When the recording medium is irradiated with the light spot 802 and an upward external magnetic field is applied at the same time, only the magnetization of the heated fine particles is inverted and the magnetic particles are directed upward. In this example, as shown in FIG. 9B, since the light spot 802 covers three of the magnetic fine particles 102,
The magnetic fine particle group 803 has reversed magnetization. Next, FIG.
As shown in (c), the light spot 802 is irradiated while the disk is moved by one of the magnetic fine particles 102,
Apply a downward external magnetic field. As a result, only the magnetic particles 805 out of the magnetic particles 803 maintain the upward magnetization, and the magnetic particles 804 have the downward magnetization. In this way, by controlling the light spot and the disk so as to be shifted by a distance corresponding to one size of the magnetic fine particles 102, it is possible to control the magnetization direction of the small fine particles even with a large light spot. In addition, as described above, 2
In the case of writing information by two times of light irradiation and magnetic field modulation synchronized with it, the shape of the bit as a recording result should be a crescent shape as shown in JP-A-8-249751, but as in the present invention, When the magnetic fine particles 102 are independent, the recording conforms to the shape of the magnetic fine particles 102. However, the shape of the light spot and the shape of the magnetic fine particles need not exactly match. Further, the composition and the shape may be such that the temperature distribution is relatively uniform and the magnetization of the fine-grained natural body is reversed.
It may be rectangular as shown in FIG. As described above, when a medium in which the shape of the magnetic fine particles is rectangular in which the direction perpendicular to the track direction is long is produced, a signal / signal detected by the GMR head is used.
Reproduction with a large noise ratio becomes possible.

Embodiment 7 FIG. 10 shows another embodiment. This embodiment is essentially the same as Embodiment 5 in which writing is performed by controlling the temperature of the magnetic fine particles 102 by irradiating the irradiation light 709 described with reference to FIG. 8, but the magnetic head 107 is moved to the main body side. The difference is that a magnetic field is applied to the coil 906 in a fixed form and the tip of the optical fiber 708 is fixed to the arm 105. In the fifth embodiment, the irradiation light 70
9 was irradiated from below the substrate 101 of the disk 100, it was necessary to use an optically transparent substance for the substrate 101. In this embodiment, since the irradiation light 709 is irradiated from above the disk 100, Such restrictions are eliminated. When the size of the spot of the irradiation light 709 can be made substantially the same as the size of the magnetic fine particles 102, a large coil 906 that can apply a uniform magnetic field over a relatively wide area is used. To apply an external magnetic field. Therefore, unlike the magnetic head 107, there is no need to finely process the coil 906.

It should be noted that, instead of the GMR head 106, another magnetic sensor having the required sensitivity and resolution may be used. For example, the tunneling magnetoresistance effect (TM
R) or a head using the colossal magnetoresistance effect (CMR).

In place of the optical fiber 708 having an opening, another optical system which can be locally heated, such as a solid immersion lens, may be used. In addition, as a heating means, heating may be performed locally by bringing an electric current from a probe such as a scanning tunneling microscope or an atomic force microscope or by bringing a heated probe close thereto, without using light. The relative movement between the recording medium and the GMR head 705 does not depend on the rotation of the disk, but may be a moving mechanism using a piezo element or a linear motor. Further, by using in combination with a medium as disclosed in JP-A-10-233015, it is possible to secure stable retention of recording and easiness of rewriting.

[0044]

According to the present invention, the magnetization direction of any fine particles on the substrate can be controlled. Therefore, by using the magnetization direction of the fine particles as a unit of information, the present invention can provide a recording medium, a recording device, and a recording method effective for recording information.

[Brief description of the drawings]

FIGS. 1A and 1B are diagrams showing an example of a magnetic recording apparatus according to the present invention, in which FIG. 1A is a plan view schematically showing a magnetic recording apparatus, and FIG. Sectional drawing which expands and shows a part.

FIG. 2 is a schematic diagram showing a difference between a signal from a recording medium to which the present invention is applied and a signal from a conventional magnetic continuous film.

FIG. 3 is a schematic diagram showing a plan view of a disk to which the second embodiment of the present invention can be applied.

FIG. 4A is a schematic diagram showing a part of an array of fine particles having in-plane anisotropy when the recording medium of Example 3 is viewed from above, and FIG. FIG. 4 is a schematic diagram showing a signal waveform when reproduced in FIG.

5A is a plan view schematically illustrating a fourth embodiment of the present invention, and FIG. 5B is a cross-sectional view illustrating a recording unit and a part of a recording medium in an enlarged manner.

6A is a diagram illustrating a detection signal of the GMR head according to the fourth embodiment illustrated in FIG. 5; FIG. 9 is a diagram showing a deviation Δθ of an axis position (time) until the operation is performed.

FIG. 7 is a schematic diagram showing a plan view of another embodiment of the disk to which the fourth embodiment of the present invention can be applied.

FIG. 8 is a block diagram illustrating a configuration of a magnetic recording apparatus according to a fifth embodiment of the present invention.

FIGS. 9A to 9D are conceptual diagrams illustrating that recording can be performed normally even when the size of the light spot in the fifth embodiment shown in FIG. 8 is larger than the magnetic fine particles.

FIG. 10 is a block diagram showing a configuration of a magnetic recording apparatus according to a sixth embodiment of the present invention.

[Explanation of symbols]

100: recording medium, 101: substrate, 102: magnetic fine particles, 103: non-magnetic material, 104: protective film, 105: arm, 106: GMR head, 107: recording head, 10
8: magnetic fine particle position detecting device, 109: magnetic coil driving device, 110: moving mechanism, 201: magnetic fine particle, 20
2: non-magnetic material, 204: recording bit in continuous magnetic continuous film, 3
01: magnetic fine particle array region, 302: magnetic continuous film region,
303, 606: bumps, 401: magnetic fine particles having in-plane anisotropy, 501: encoder, 502: correction signal input terminal, 603: portion having tracking information, 60
4: recording zone, 605: recording zone, 707: laser source, 708: optical fiber, 709: irradiation light, 71
0: lens, 802: light spot, 803: group of fine particles with reversed magnetization, 804: group of fine particles with reversed magnetization, 805:
Fine particles with reversed magnetization, 906: coil.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hideo Matsuyama 1-280 Higashi-Koigakubo, Kokubunji-shi, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd. Central Research Laboratory F-term (reference) 5D031 AA04 CC20 EE07 EE08 HH20 5D033 AA10 BB01 BB14 CA09 5D091 AA08 CC05 CC17 CC26 GG40 HH20

Claims (12)

[Claims] 1. A recording medium on which isolated magnetic fine particles are arranged, a magnetic sensor for detecting the position of the magnetic fine particles, a means for reversing the magnetization of the magnetic fine particles, and a means for reversing the magnetic sensor and the magnetization An arm for holding the means, and a magnetic recording apparatus comprising means for relatively moving the arm and the recording medium,
Determined from the signal of detecting the presence of the magnetic fine particles of the magnetic sensor, the relative positional relationship between the magnetic sensor and the means for reversing the magnetization of the magnetic fine particles, and the relative speed between the recording medium and the magnetic sensor. A magnetic recording apparatus characterized in that magnetization is performed by means for reversing the magnetization of the magnetic fine particles in order to reverse the magnetization of the magnetic fine particles to be recorded at a given timing. 2. The recording medium according to claim 1, further comprising a continuous recording surface provided on a part of said recording medium, wherein said magnetic sensor detects magnetization obtained by means for reversing the magnetization of said magnetic fine particles on said recording surface and said recording. 2. The recording apparatus according to claim 1, wherein a relative positional relationship between the magnetic sensor and a means for reversing the magnetization of the magnetic fine particles is determined from relative velocity data between the medium and the magnetic sensor. 3. A motor for rotating the recording medium, and means for detecting an axial position of a rotating shaft of the motor, wherein a magnetization operation by means for reversing the magnetization of the isolated magnetic fine particles is performed with respect to the axial position. 2. The recording apparatus according to claim 1, wherein the relative positional relationship between the magnetic sensor and the means for reversing the magnetization of the magnetic fine particles is determined by shifting the magnetic sensor and evaluating the result. 4. The recording medium has a portion having tracking information on a recording surface side thereof, and replaces data of means for detecting an axial position of a rotation axis of a motor for rotating the recording medium, instead of data of the recording medium. 4. The recording apparatus according to claim 3, wherein the recording apparatus uses tracking information. 5. The magnetic recording apparatus according to claim 1, wherein the magnetic fine particles of the recording medium have perpendicular anisotropy or in-plane anisotropy. 6. A method according to claim 1, wherein the means for reversing the magnetization of the magnetic fine particles is a light spot for controlling a temperature of the magnetic fine particles and a magnetization signal acting on the isolated magnetic fine particles of the recording medium. The magnetic recording device according to any one of the above. 7. The magnetic recording apparatus according to claim 6, wherein one of the means for giving the magnetization signal and the means for giving a light spot is held by the arm, and the other is held by the main body. 8. The size of a light spot for controlling the temperature of the magnetic fine particles is a size that covers a plurality of isolated magnetic fine particles, and writing is performed by setting a spot by a distance corresponding to the size of the magnetic fine particles. 8. The magnetic recording apparatus according to claim 1, wherein the magnetic recording is performed while moving. 9. The method according to claim 1, wherein heating is performed locally from a sharply pointed probe in place of a light spot for controlling the temperature of the magnetic fine particles. Magnetic recording device. 10. The non-magnetic material surrounding the substrate and the magnetic material of the recording medium is an optically transparent material.
The magnetic recording device according to any one of the above. 11. The non-magnetic material surrounding the magnetic fine particles is a substance having a lower thermal conductivity than the fine particles.
The magnetic recording device according to any one of the above. 12. The magnetic recording apparatus according to claim 6, wherein the shape of the magnetic fine particles is a rectangular shape whose direction perpendicular to the track direction is long.