JP2003123334A - Magnetic head and recorder furnished with the magnetic head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic head which generates a magnetic field at a very high speed. SOLUTION: A magnetic head 30 is provided with a magnetic coil 34, a magnetic core 35 and a lens which condenses a laser beam upon the magnetic core. The magnetic core 35 is irradiated with the laser beam which is pulse- modulated according to recorded information. The magnetic core 35 is instantly heated up to the Curie temperature or higher and looses magnetism. Thus the magnetic core 35 does not function and does not generate a magnetic field any more even when an electric current is supplied to a magnetic coil 34. The magnetic core 35 functions when the magnetic core is not irradiated with the laser beam and the magnetic field is generated. The magnetic field modulated at a high speed is generated by the magnetic core 35 by modulating the laser beam at a high speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head for applying an external magnetic field to a recording medium and a recording apparatus equipped with the same, and more particularly to a magnetic head capable of controlling the applied external magnetic field at high speed. The present invention relates to a head and a recording device including the head.

[0002]

2. Description of the Related Art In recent years, with the spread of the Internet and the speeding up of computers, the information handled has become more diverse.
The amount of information is also increasing dramatically. Therefore, in the field of magnetic recording such as a magnetic recording medium and a magneto-optical recording medium, high density recording, large capacity and high speed recording are required.

Various recording technologies have been proposed in order to meet such demands. As one example, the magneto-optical recording technology used in the magneto-optical disk and the magnetic recording technology used in the magnetic disk are proposed. A technique (hereinafter referred to as heat-assisted magnetic recording) of forming a fine magnetic domain in a recording layer having a high coercive force by fusion is known. In the thermally assisted magnetic recording, when reproducing recorded information, a leakage magnetic field from the magnetic recording medium is detected by using a reproducing element mounted on a magnetic head, as in the case of reproducing a conventional magnetic disk.
The use of this heat-assisted magnetic recording enables magnetic recording resistant to thermal fluctuations, and therefore expectations for heat-assisted magnetic recording are increasing.

On the other hand, the density of magneto-optical recording media is also being increased, and various recording media realizing high density recording such as magnetic super resolution (MSR) and magnetic domain expansion reproduction (MAMMOS) have been developed. There is.

[0005]

By the way, in the data communication field, there has been a shift from electrical data communication to optical data communication,
It is possible to transmit a large amount of data at extremely high speed. Currently 100 Gb for optical data communication
Data can be transmitted at a transmission rate of ps (gigabit / second). On the other hand, in magnetic recording, the data transfer rate to the recording medium is currently about 700 to 800 MHz at maximum, which is extremely slower than the transmission rate of optical data communication. Thus, there is a large gap between the data transfer rate of optical data communication and the data transfer rate of a recording medium.

In both recording methods of heat-assisted magnetic recording and magneto-optical recording, it is necessary to apply an external magnetic field to the medium during recording. A magnetic head is usually used as a magnetic field applying unit to the recording medium. In order to improve the data transfer rate to the recording medium, it is necessary to drive the magnetic head at high speed to increase the recording frequency and to switch the external magnetic field at high speed. However, in order to generate an external magnetic field sufficient for recording from the magnetic head, it is necessary to increase the inductance of the magnetic head, which makes it difficult to switch the magnetic field at high speed.

The present invention has been made to solve the problems of the prior art, and an object thereof is to provide a magnetic head capable of switching a magnetic field at an extremely high speed.

[0008]

According to the present invention, there is provided a magnetic head for applying a magnetic field to a recording medium, the magnetic head comprising a magnetic material, and a magnetic field generating section for generating a magnetic field; A heating means for heating the part;

The magnetic head of the present invention controls the magnetic field generated by the magnetic field generating section by heating the magnetic material forming the magnetic field generating section. That is, it is possible to interrupt the generation of the magnetic field from the magnetic field generation unit by heating the magnetic field generation unit to, for example, the Curie temperature of the magnetic material or more to eliminate the magnetization of the magnetic material, while heating the magnetic field generation unit. The magnetic field can be generated from the magnetic field generation unit by stopping and cooling the magnetic material below the Curie temperature to restore the magnetization of the magnetic material. By controlling the heating of the magnetic field generator according to the recorded information, the magnetic field generated from the magnetic head can be controlled according to the recorded information. Since the disappearance of the magnetization of the magnetic material and the responsiveness of reproduction due to heating are extremely fast, it is possible to generate a high frequency modulated magnetic field by switching the heating and cooling operations of the magnetic field generator at high speed.

The magnetic head of the present invention may be provided with a magnetic coil, and a magnetic core may be provided inside the magnetic coil as a magnetic field generating portion. In this case, the magnetic field generated from the magnetic core can be controlled by heating the magnetic core with the heating means.

In the present invention, a laser light source or a heater can be used as a specific means for heating the magnetic material of the magnetic field generating portion to the Curie temperature or higher, and the laser light source is particularly preferable. By irradiating the magnetic core with the laser light emitted from the laser light source, the magnetic material can be instantly heated to the Curie temperature or higher. At this time, the external magnetic field can be turned on and off at an extremely high speed by irradiating the laser light in a pulsed manner. The reason will be described below.

To improve the data transfer rate in magnetic recording, the modulation frequency of the magnetic field generated by the magnetic head must be increased. For example, in order to obtain the same transfer rate of 100 Gbps as in optical data communication, it is necessary to increase the modulation frequency of the magnetic field generated by the magnetic head to 100 GHz (gigahertz). However, in general,
Co and F used in the recording layer of magnetic disks
When a magnetic field having a modulation frequency of 1 GHz or higher is applied to a magnetic material containing a ferromagnetic element such as e or Ni, the magnetic energy of the high frequency magnetic field is absorbed by the ferromagnetic element such as Co, Fe or Ni in the recording layer. It is known that a phenomenon called ferromagnetic resonance occurs. Therefore, in magnetic recording, it has been considered that magnetization reversal of the recording layer does not occur due to such ferromagnetic resonance, and information cannot be recorded in the recording layer at a transfer rate of 1 Gbps or higher. Further, the phenomenon of the ferromagnetic resonance also occurs in the magnetic pole of the magnetic head for generating the magnetic field for recording. For this reason, it has been considered that there is a limit to writing information on a magnetic recording medium at high speed.

However, the inventors of the present invention, after orienting the magnetic moment of the GdFeCo amorphous film in a predetermined direction, apply a magnetic field to the amorphous film in the opposite direction to the direction of the magnetic moment from the outside. Laser light with a wavelength of 800 nm 10
0fs (100 × ^{10 -15} sec) was between irradiated, as shown in FIG. 13, after irradiation 500fs (500 × 10 ^-
It was found that the magnetic moment M _up or M _down became zero in ¹⁵ seconds) and the magnetic moment disappeared. It was also found that the magnetic moment that appeared when the portion of the amorphous film irradiated with the laser light was cooled was inverted in the direction of the magnetic field applied from the outside. This result shows that the magnetization of the magnetic material is 500 fs (half of 1 ps).
This means that the magnetization of the magnetic material can be expressed in a time shorter than 1 ps, considering the time until the laser light irradiation part is cooled and the magnetization appears. That is, under a magnetic field of constant intensity, the magnetic material is irradiated with light having an intensity of 6 mJ / cm ² or more at a cycle of 1 ps, which is 1 TH.
It was found that by modulating the laser beam with a frequency of z (terahertz) and irradiating the magnetic substance, the onset and disappearance of the magnetization of the magnetic substance can be switched at high speed.

Therefore, in the present invention, the magnetic field generated from the magnetic field generating section is controlled by irradiating the magnetic material forming the magnetic field generating section of the magnetic head with a laser beam which is modulated in a pulsed manner at high speed.

For example, when the magnetic head is composed of a magnetic coil, while applying a constant magnetic field to the magnetic core of the magnetic coil, the magnetic core is irradiated with pulse-modulated laser light at a frequency of 1 GHz or higher. In this way, when the magnetic core is instantaneously irradiated with laser light at a predetermined intensity, the magnetic material forming the magnetic core instantaneously loses its magnetization and loses its function as a magnetic core, causing a current to flow through the magnetic coil. However, almost no magnetic field is generated from the magnetic core. After a lapse of a predetermined time after the laser light is instantaneously irradiated, the magnetic material forming the magnetic core becomes magnetized. At this time, by continuing to flow an electric current through the magnetic coil to generate a constant magnetic field in the magnetic core, the magnetic material forming the magnetic core has its magnetic moment directed in the direction of the magnetic field of the magnetic coil and functions as a magnetic core. Come to do. In this way, the magnetic field generated from the magnetic core of the magnetic coil can be turned on and off at high speed. By using such a magnetic head, the magnetic field applied to the recording medium can be turned on and off at high speed, so that magnetic recording at a data transfer rate of 1 Gbps or higher can be realized.

In the present invention, when the magnetic head is formed by using the magnetic coil, the magnetic material forming the magnetic core of the magnetic coil may include a soft magnetic material. Examples of such soft magnetic material include CoFeNiSiB, FeTaC, and CoF.
eSiB or the like can be used. The periphery of the magnetic core is preferably covered with an insulator, and the magnetic coil is preferably formed through the insulator. For the insulator, for example, SiN, SiO or the like can be used.

Further, it is desirable to form a heat dissipation material near the magnetic core of the magnetic coil. Thereby, the magnetic core heated by the laser light irradiation can be rapidly cooled.
The heat dissipation material is preferably an Al alloy, Au or Ag or an alloy thereof, such as AlTi or AlTiS.
i, AlNi, AlTa, AlPt, AlCu, Au,
Ag or the like can be used.

In the present invention, the magnetic material forming the magnetic field generating portion preferably has a Curie temperature in the range of 80 ° C to 300 ° C. This allows the magnetic material to be heated to such a temperature with a practical laser output.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the recording method according to the present invention will be specifically described, but the present invention is not limited thereto.

FIG. 1 shows a schematic sectional view of an information recording medium used in the examples described later. The information recording medium 10 includes a backing layer 2, a magnetic layer (recording layer) 3 and a protective layer 4 on a substrate 1. In FIG. 1, the substrate 1 is an arbitrary substrate such as a resin material such as polycarbonate or amorphous polyolefin molded into a desired shape, a glass substrate formed into a desired shape, or a metal substrate such as aluminum. Can be used. The backing layer 2 is a layer for efficiently dissipating heat to the outside during recording, for example, A
It is formed using u, Ag, Cu, Al, Pd, Rh, or an alloy thereof. The magnetic layer 3 is a layer for recording information, and is, for example, TbFeCo, DyFeC.
o, it can be amorphous film and the rare earth and transition metals, such as TbDyFeCo, Pd / Co multilayer film, PtCo alloy, also be used other known magnetic recording materials such as L1 ₀ type magnetic alloy. The protective layer 4 is a layer for protecting the backing layer 2 and the magnetic layer 3 formed on the substrate 1 from chemical adverse effects such as corrosion. For example, SiN, carbon, AlN, Si
O, ZnS, is formed from ZnS-SiO _2. The layers 2 to 4 can be formed by a dry process such as continuous sputtering using a magnetron sputtering device.

Next, the recording apparatus of the present invention will be described. FIG. 2 shows a schematic configuration diagram of the recording apparatus. Recording device 2
00 is mainly the signal generator 21 and the laser controller 2.
2, a laser light source 23, a magnetic head 30, and an information recording medium 10. In the recording device 200 of FIG. 2, the information recording medium 10 has the magnetic head 3 on the surface on which the magnetic layer 3 exists.
It is mounted in the recording device so that 0 is positioned, and is rotated at a predetermined rotation speed by a rotation driving device (not shown).

The laser control device 22 can control the laser light emitted from the laser light source 23 to be pulsed light which is intermittent at regular intervals based on the recording signal from the signal source 21. For example, if the recording signal of the signal source 21 is 1 Gb
In the case of the speed of ps to 1000 Gbps, the laser control device 22 can perform control so that the time interval between the rise and the fall of the pulsed laser light is 100 fs to 100 ps. As a means for pulsing the laser light, instead of the laser control device 22, for example, a chopper may be provided on the light emission side of the laser light source 23.

The laser light source 23 has, for example, a wavelength of 200n.
It can be configured by using a semiconductor laser having m to 1400 nm and an output of 5 mW to 50 mW. When forming a minute recording mark in the magnetic layer of the information recording medium, since the spot diameter by the laser light is proportional to the wavelength of the laser light,
It is preferable that the wavelength of the laser light is short. When recording data, the laser light source 23 is set by the laser control device 22 to 1
It is possible to emit pulsed light that is turned on and off at a clock frequency of GHz to 1 THz. The light emitted from the laser light source 21 is reflected by the mirror 28 toward the magnetic head 30.

In FIG. 2, a magnetic head according to the present invention shown in the following embodiments can be used as the magnetic head 30. An embodiment of a magnetic head of the present invention will be described with reference to the drawings.

[0025]

Embodiment 1 FIG. 3 is a schematic configuration diagram of a magnetic head of this embodiment.
Shown in. FIG. 3A shows a magnetic head 30 with a slider 32.
It is a schematic sectional drawing when it cut | disconnects in the longitudinal direction. The magnetic head 30 mainly includes a slider 32 and a lens 33 as shown in FIG. The slider 32 is for flying above the recording medium 10, and has a structure capable of stably flying while the recording medium 10 is rotating.
The protective film 13 is formed on the bottom surface of the slider 32,
It is possible to avoid damage to the magnetic head 30 caused by the contact of the magnetic head 30 with the recording medium 10.
Diamond-like carbon was suitable as the material for the protective film 13 from the viewpoint of strength.

A circular through hole is formed in the slider 32, and a cylindrical magnetic core 35 is fitted in the through hole. The outer periphery of the magnetic core 35 is covered with a non-magnetic heat control film 36, and the magnetic coil 34 is provided outside the non-magnetic heat control film 36.
Are formed. The magnetic core 35 is a soft magnetic material and is made of a material that reaches the Curie temperature when irradiated with the laser beam 39. In this embodiment, a CoFeNiSiB type amorphous material known as a high frequency magnetic core material is used, and a coercive force of 180 mA / m at a Curie temperature of about 210 ° C.
The magnetic core 35 of a soft magnetic material having a certain degree was formed. If the material used for the magnetic core 35 is a soft magnetic material and reaches the Curie temperature when irradiated with the laser beam 39, CoF
The material is not limited to the eNiSiB-based amorphous material.

The non-magnetic heat control film 36 covering the outer periphery of the magnetic core 35 can accelerate the cooling of the magnetic core 35 after the irradiation of the laser light 39 to the magnetic core 35 is stopped. It is preferable that the non-magnetic heat control film 36 has a multilayer film structure. For example, SiN is used for a portion that directly covers the outer periphery of the magnetic core 35, and the outside thereof is a metal film such as an Al alloy having a high thermal conductivity. Can be coated. As the Al alloy, for example, an AlTi alloy containing Ti or the like can be used. The magnetic coil 34 can have various shapes as shown in FIG. 4A or 4B. The lens 33 arranged directly above the magnetic core 35 can heat the magnetic core 35 to a desired temperature by condensing and irradiating the laser light emitted from a laser light source (not shown) on the magnetic core 35.

Further, in FIGS. 3 (a) and 3 (b),
The recording head is configured such that a heating laser beam is continuously irradiated from a laser light source (not shown) to the magnetic head from the front side in the traveling direction of the recording medium. A predetermined area can be heated. The magnetic head can pass through the area heated by the laser light irradiation, and a magnetic field can be applied to the heated area of the recording medium by the magnetic head.

Next, the principle of high-speed switching by applying an external magnetic field by the magnetic head 30 will be described. Magnetic head 3
By driving 0 with a driver (not shown), a direct current is passed through the magnetic coil 34. The current passed through the magnetic coil is controlled by such a driver. If a direct current is passed through the magnetic coil 34 without irradiating the magnetic core 35 of the magnetic head 30 with the laser light 39, an external magnetic field H ₊ can be generated from the magnetic coil 34 as shown in FIG. 3B. . At this time, the magnetic core 35 is below the Curie temperature because it is not irradiated with the laser light 39, and functions as a soft magnetic material. As a result, it becomes possible to apply the external magnetic field H _{+ having} a magnetic field strength sufficient for recording on the recording medium 10. A perpendicular magnetic recording medium was used as the recording medium 10. Here, as shown in FIG. 3A, the laser light 39 is transmitted through the lens 33 to the magnetic core 3
When irradiated to 5, the soft magnetic material of the magnetic core 35 reaches the Curie temperature and loses its function as a magnetic core. Therefore, even if a direct current flows through the magnetic coil 34, an external magnetic field having a sufficient magnetic field strength cannot be applied to the recording medium, and if the flying height of the magnetic head 30 is appropriate, the external magnetic field reaches the recording medium 10. The absolute value of the magnetic field decreases.

After that, when the irradiation of the laser light 39 to the magnetic core 35 is stopped, the heat escapes to the non-magnetic heat control film 36 covering the magnetic core 35, the temperature of the magnetic core 35 is rapidly cooled, and the Curie is cured. It will be below the temperature. The function of the soft magnetic body of the magnetic core 35 having the Curie temperature or lower is restored again, and it becomes possible to apply an external magnetic field having sufficient magnetic field strength to the recording medium. In this way, by switching on / off of the laser light applied to the magnetic core 35 at high speed, the application of the external magnetic field from the magnetic head 30 can be switched at high speed. That is, as shown in FIG. 5A, the laser light 7 is turned on and off while being irradiated in a pulsed manner, and as shown in FIG.
_DC is applied to the magnetic coil 4. As shown in FIGS. 5A and 5C, the magnetic field generated from the magnetic head when laser light is irradiated is zero, and when the laser light irradiation is stopped, the magnetic head is directed downward from FIG. 3B. External magnetic field H
₊ Is generated. This makes it possible to switch the magnetic field generated from the magnetic head as shown in FIG. In FIG. 3B, it is assumed that the magnetization of the recording layer of the recording medium is initialized upward, and if the recording direction is downward in the figure, a magnetic field is generated from the magnetic head when the laser light irradiation is stopped. A downwardly magnetized recording mark is formed on the recording layer, and information is recorded on the recording layer. Therefore, by controlling the laser beam 39 irradiating the magnetic core with a driver (not shown) so as to correspond to the channel bit of the information desired to be recorded, extremely high-speed recording becomes possible.

In this embodiment, the magnetic head 30 is used to record a signal on the information recording medium 10 having a diameter of 300 mm. At the time of recording, while applying an electric current to the magnetic coil 34 of the magnetic head 30 to generate an external magnetic field having an intensity of 200 [Oe], the laser light pulse-modulated at a frequency of 10 GHz according to the recorded information is 6 mJ / cm ^2. Strength of magnetic core 3
Irradiate 5. As a result, the magnetic core 35 of the magnetic head 30
From the above, since a magnetic field is generated according to the recorded information, the magnetic field is applied to the recording medium and a magnetic mark is formed on the recording layer.
At this time, the pulse width of the pulsed light with which the magnetic core 35 is irradiated is 1
00fs (femtosecond), pulse interval is 100ps
Set to (picoseconds). Further, the recording medium 10 is driven by a rotation driving device (not shown) to rotate the recording medium 10 with respect to the magnetic head 30 at 18000 rpm. Then
After positioning the magnetic head 30 at the position of φ260 mm,
Record the recording signal. As a result, a magnetic mark of about 25 nm was formed on the recording layer, and a recording signal could be recorded on the recording layer at high speed.

[0032]

Second Embodiment A magnetic head of this embodiment is shown in FIGS. FIG. 6A is a schematic sectional view of the magnetic head 60, and FIG. 6B is a plan view of the magnetic head 60 seen from above. The magnetic head 60 used in this embodiment has a magnetic core 35.
Is a cylindrical magnetic core 6 having a diameter extremely smaller than the spot diameter 68 of the laser light focused by the lens 33.
5 is mounted, and a transparent dielectric 64 is provided around the magnetic core 65.
Are formed. The magnetic head 60 has a magnetic core 65.
Since the periphery of is surrounded by the transparent dielectric 64, the laser light condensed by the lens 33 can be transmitted through the transparent dielectric 64 and reach the recording medium 10 located immediately below the magnetic head 60. . Therefore, the laser beam 39 can heat not only the magnetic core 65 but also a predetermined area of the recording medium 10. Further, the magnetic head 60 is
A permanent magnet 61 is mounted for offsetting the external magnetic field during laser irradiation. The permanent magnet 61 has an annular structure, and the magnetic coil 34 is positioned inside the permanent magnet 61. The permanent magnet 61 is arranged such that its center substantially coincides with the center of the magnetic core 65, and can generate an upward magnetic field in the drawing at the position of the magnetic core 65. Magnetic coil 3
As shown in FIG. 6B, 4 was formed in an elliptical shape in order to reduce crosstalk from adjacent tracks. Magnetic core 6
The position of 5 is the beam from the spot center in consideration of the fact that the thermal center generated by laser light irradiation when the magnetic head is relatively moved with respect to the recording medium is displaced rearward from the spot center in the beam traveling direction. It was formed so as to be shifted backward with respect to the traveling direction.

Since the magnetic head has the above-described structure, it is possible to use a heat-assisted magnetic recording medium or a magneto-optical recording medium as the recording medium 10. That is, since the diameter of the magnetic core 65 is extremely smaller than that of the spot diameter 68 and the periphery of the magnetic core 65 is surrounded by the transparent dielectric 64, the laser light 39 passes through the transparent dielectric 64 and then
It is possible to reach the recording medium 10 and heat a predetermined area of the recording medium 10. This makes it possible to locally reduce the coercive force of the laser light irradiation portion of the recording medium 10 and perform recording by applying an external magnetic field having a relatively weak magnetic field strength. As shown in FIG. 6A, the laser light 39 is passed through the magnetic core 65.
However, the external magnetic field generated from the magnetic coil 34 itself becomes small because the magnetization of the magnetic core 65 disappears.
Since the external magnetic field in the opposite direction is applied from the permanent magnet 61,
An offset of the external magnetic field at the recording position of the recording medium 10 can be realized.

On the other hand, as shown in FIG.
When there is no laser light irradiation on the magnetic core 65, the magnetic core 65 functions, and the external magnetic field is applied to the recording medium in the direction opposite to that when the laser light is irradiated. That is, the external magnetic field application from the magnetic head can be switched at high speed by switching on / off of the laser light applied to the magnetic core 65. For example, when the laser light is turned on and off as shown in FIG. 7A while being pulsed, and the direct current I _{DC is} passed through the magnetic coil as shown in FIG. 7B, as shown in FIG. 7C. When the laser light is on, a magnetic field H ₋ is generated from the magnetic head due to the external magnetic field offset by the permanent magnet 61, and when the laser light is off, a magnetic field H ₊ is generated from the magnetic head. This makes it possible to switch the magnetic field generated by the magnetic head as shown in FIG.

As described above, the magnetic head of this embodiment can switch the direction of the external magnetic field at the recording position of the recording medium by the external magnetic field offset by the permanent magnet 61. The magnetic field H ₊ of FIG. 7C shows a downward magnetic field in FIGS. 6A and 6C, and the magnetic field H ₋ of FIG.
An upward magnetic field is shown in (a) and (c).
When the recording direction is upward in FIGS. 6A and 6C, an upward magnetic field H ₋ is generated from the magnetic head when the laser beam is irradiated, and a recording mark with upward magnetization is formed in the recording layer. Information is recorded on the layers. The magnetic head used in the present embodiment is capable of high density recording because the diameter of the magnetic core 65 is very small, and can switch the external magnetic field at high speed, so that extremely high speed and high density recording is possible. Is possible.

In this embodiment, a signal is recorded on the information recording medium 10 having a diameter of 300 mm by using the magnetic head 60. At the time of recording, while applying an electric current to the magnetic coil 34 of the magnetic head 60 to generate an external magnetic field having an intensity of 200 [Oe], laser light pulse-modulated at 6 GHz at a frequency of 10 GHz is 6 mJ / cm ² The magnetic core is irradiated with the intensity of. As a result, a magnetic field having a polarity corresponding to the recorded information is generated from the magnetic core of the magnetic head. Further, the laser light passes through the transparent dielectric existing around the magnetic core and heats the magnetic field application portion of the recording medium at a desired temperature. At this time, the pulse width of the pulsed light applied to the magnetic core is 100 fs (femtoseconds), and the pulse interval is 100 ps (picoseconds).
Further, the recording medium 10 is driven by a rotation driving device (not shown) to move the recording medium 10 to the magnetic head 60 by 180 degrees.
Rotate at 00 rpm. Then, the magnetic head 60 is
After positioning at the position of 290 mm, the recording signal is recorded. As a result, a magnetic mark of about 30 nm was formed on the recording layer, and a recording signal could be recorded on the recording layer at high speed.

[0037]

Third Embodiment FIG. 8 shows a schematic diagram of a magnetic head of the present embodiment. The magnetic head 80 shown in FIG.
1, a magnetic core 82, an optical waveguide member 83, and a lens 84. Although not shown in FIG. 8, the magnetic coil 81 and the magnetic core 8
2, the optical waveguide member 83 and the lens 84 are the same as those in the first and second embodiments.
The magnetic head can be incorporated in the slider in the same manner. In FIG. 8, the magnetic core 82 is made of a soft magnetic material. Further, as shown in FIG. 8, the magnetic core 82 is formed in a multi-stage shape such that the outer diameter of the upper portion 82a thereof is larger than the outer diameter of the middle portion 82b. The magnetic coil 81 is wound around the middle portion 82a of the magnetic core 82. The lower portion 82c of the magnetic core 82 is tapered.

The optical waveguide member 83 is made of a material having optical transparency.
Fee, eg GeO_TwoAnd P_TwoO₅, B _TwoO_ThreeEtc.
SiO_TwoAre formed from. The optical waveguide member 83 is shown in FIG.
As shown in FIG. 8, the outer diameter of the upper part 83a is lower than the lower part 83b.
Is formed in a multi-stage shape so that it is larger than the outer diameter of
It

When pulsed laser light enters the magnetic head 80 from the laser light source 23 of the recording apparatus shown in FIG. 2, the laser light is condensed by the lens 84, and then the magnetic core 82 and the optical waveguide member 83. Pulse irradiation of the upper surface of. Figure 8
As shown in (a), when the magnetic core 82 is irradiated with the laser light, the entire magnetic core 82 is heated, and the soft magnetic material forming the magnetic core 82 is heated to the Curie temperature or higher. As a result, even if a current is supplied to the magnetic coil 81, no magnetic field is generated from the tip portion 82d of the magnetic core 82. In addition, the laser light incident from above the optical waveguide member 83 is
Exits from the tip portion 83c through the inside of the. The laser light emitted from the tip portion 83c of the optical waveguide member 83 heats the magnetic layer of the information recording medium 10 to a predetermined temperature.

As shown in FIG. 8B, when the laser light is not applied to the magnetic core 82, the soft magnetic material forming the magnetic core 82 exhibits magnetization and functions as a magnetic core. The magnetic coil 81 causes a magnetic field H from the tip 82d of the magnetic core 82.
Occurs. At this time, the optical waveguide member 83 is not irradiated with the laser light, so that the magnetic layer of the recording medium is not heated.

Depending on the relative moving speed of the magnetic head with respect to the information recording medium, the center of the heat spot generated in the magnetic layer of the information recording medium by the laser light irradiation from the optical waveguide member 83 is closer to the center of the laser light than the center of the light spot. It shifts backward with respect to the traveling direction. Therefore, the rotational speed of the information recording medium is adjusted so that the magnetic field generated from the magnetic core when the laser light irradiation to the magnetic core is stopped is applied to the center of the heat spot generated in the magnetic layer of the information recording medium by the laser light irradiation. By adjusting, information can be recorded on the information recording medium. Alternatively, even if the information recording medium is not irradiated with laser light, information may be recorded on the information recording medium by applying a magnetic field generated from the magnetic core when the irradiation of the laser light onto the magnetic core is stopped.

[0042]

Fourth Embodiment FIG. 9 shows a schematic view of another embodiment of the magnetic head according to the present invention. The magnetic head 90 uses a DC power source 9
1, a magnetic coil 92, a magnetic core 93, and a lens 94. Although not shown in FIG. 9, the magnetic coil 92 and the magnetic core 9
The lens 3 and the lens 94 can be incorporated in the slider as in the magnetic heads of the first and second embodiments. The magnetic core 93 is
It is formed of a rod-shaped soft magnetic material. The tip 93a of the magnetic core 93 is tapered. As the soft magnetic material forming the magnetic core 93, a material that reaches the Curie temperature when irradiated with laser light is used. In this example, CoFeN
It was formed using iSiB.

As shown in FIG. 9A, the magnetic core 93 has
The pulse-modulated laser light emitted from the laser light source 23 of the recording apparatus shown in FIG. 2 is obliquely applied to the magnetic core 93. By the irradiation of such pulsed laser light, the entire magnetic core 93 is instantaneously heated to the Curie temperature or higher only when the laser light is instantaneously irradiated, and the function as the magnetic core is lost. Therefore, even if current is supplied to the magnetic coil 92 from the DC power supply 91, no magnetic field is generated from the tip portion 93a of the magnetic core 93.

After the irradiation of the laser beam, the soft magnetic material forming the magnetic core 93 is cooled and becomes lower than the Curie temperature, so that the function as the magnetic core is restored. At this time, if a current is supplied to the magnetic coil 92 from the DC power source 91, a recording magnetic field is generated from the tip portion 93a of the magnetic core 93, as shown in FIG. It becomes possible to record information. As described above, also in the magnetic head of this embodiment, the on / off of the magnetic field generated from the magnetic head can be switched at high speed by switching the laser light on / off at high speed.

[0045]

Fifth Embodiment FIG. 10 shows still another embodiment of the magnetic head according to the present invention. The magnetic head 100 includes a first magnetic coil 101, a second magnetic coil 102, a magnetic core 103, a first lens 104 and a second lens 105. Although not shown in FIG. 10, the first magnetic coil 101, the second magnetic coil 102, the magnetic core 103, the first lens 104, and the second lens 105 are provided on the slider similarly to the magnetic heads of the first and second embodiments. Can be incorporated. The magnetic core 103 has a first
The magnetic coil 101 and the second magnetic coil 102 are wound. The first lens 104 can focus laser light from a laser light source (not shown, which is different from the laser light source 23 in FIG. 2) and irradiate the magnetic core 103. The first lens 104 is arranged so that the condensed laser light is obliquely applied to the magnetic core 103. Further, the laser light focused by the first lens 104 is simultaneously irradiated onto a predetermined area of the information recording medium, and the light irradiation area of the information recording medium can be heated to a predetermined temperature. The laser light with which the magnetic core 103 is irradiated is modulated in a pulse shape at a constant cycle in synchronization with the channel clock. As the laser light source for the laser light with which the magnetic core 104 is irradiated, a light source different from the laser light source of the recording apparatus shown in FIG.

The first magnetic coil 101 is connected to the resistor R1 and the DC power supply 106, and the second magnetic coil 102 is connected.
Is connected to the resistor R2 and the DC power supply 107. The polarity of the magnetic core 103 when the direct current is supplied from the direct current power supply 106 only to the first magnetic coil 101 and the polarity of the magnetic core 103 when the direct current is supplied from the direct current power supply 107 only to the second magnetic coil are opposite to each other. The polarities of the DC power supplies 106 and 107 are set to opposite polarities so as to have polarities. The DC power supplies 106 and 107 constantly supply currents to the first magnetic coil 101 and the second magnetic coil 102, respectively.

The second lens 105 can focus the laser light emitted from the laser light source shown in FIG. 2 on the resistors R1 and R2 and irradiate them simultaneously.

The resistor R1 connected to the first magnetic coil 101 has such a characteristic that the resistance becomes high due to heating by the laser light irradiation and becomes low when the laser light irradiation is stopped. On the other hand, the resistor R2 has a characteristic that the resistance value becomes low due to the heating by the laser light irradiation and becomes high when the laser light irradiation is stopped.

As shown in FIG. 10 (a), when the laser beam is irradiated, the resistor R1 has a high resistance, so that almost no current is supplied to the first magnetic coil 101, and the second magnetic coil 1 is not supplied.
The current I2 is supplied only to 02. At this time, the magnetic core 10
A magnetic field H _{2 of a} polarity based on the second magnetic coil 102 is generated from the tip 103 a of No. 3.

On the other hand, as shown in FIG. 10B, when the laser beam irradiation is stopped, the resistance of the resistor R1 becomes low and the first
While the current I1 is supplied to the magnetic coil 101, the resistor R2 has a high resistance, so that almost no current is supplied to the second magnetic coil 102. As a result, a magnetic field H ₁ having a polarity based on the first magnetic coil 101, that is, a magnetic field having a polarity opposite to that at the time of laser light irradiation is generated from the tip portion 103 a of the magnetic core 103. In this way, by turning on / off the irradiation of the laser light to the resistors R1 and R2 respectively connected to the first magnetic coil 101 and the second magnetic coil 102, the tip portions 103a of the magnetic core 103 have different polarities. Magnetic fields can be generated alternately.

The laser light applied to the resistors R1 and R2 is pulsed light from the laser light source shown in FIG.
Since the pulsed light is modulated at high speed according to the recorded information, the magnetic field generated from the magnetic core 103 of the magnetic head is also modulated according to the recorded information.

As described above, the magnetic core 103 is also irradiated with the laser light pulse-modulated so as to be synchronized with the laser light applied to the resistors R1 and R2 at a predetermined intensity. As a result, the magnetization of the magnetic core 103 also disappears instantaneously.
The magnetic moment of the magnetic material forming 03 can be switched at high speed according to the magnetic field generated by the first magnetic coil 101 or the second magnetic coil 102.

By using such a magnetic head, 1
It is possible to generate an alternating magnetic field that is modulated at high speed according to recorded information at a frequency of GHz or higher.

Although the magnetic head according to the present invention has been specifically described with reference to the embodiments, the present invention is not limited to these. In the above-mentioned embodiment, the transmitted signal is guided to the magnetic head through the laser control device and the laser light source to irradiate the magnetic core of the magnetic head. However, as shown in FIG. It is also possible to amplify the light intensity of the pulse signal by a high-speed optical signal amplifier and then guide the amplified optical pulse signal to the magnetic head to irradiate the magnetic core of the magnetic head. Further, instead of the optical signal high speed amplifier, a laser excitation trigger and a high power laser may be used. Further, the optical signal transmitted through the optical fiber may be a multimode optical signal in which information is given to a plurality of wavelengths.

Further, in the magnetic head of the above-mentioned embodiment, the magnetic field generating source for applying the magnetic field to the medium is constituted by using the magnetic coil and the magnetic core. However, as shown in FIG. 12, a rod-shaped permanent magnet is used. You can also In this case, the permanent magnet may be instantaneously heated by irradiating the permanent magnet with pulsed laser light, and the magnetic field strength generated from the permanent magnet may be weakened to the extent that information is not recorded on the medium.

In the above embodiment, the disk-shaped information recording medium is used as a medium for recording information using the magnetic head, but information can be recorded on a tape-shaped or card-shaped information recording medium. it can.

In the above embodiment, the resistors R1 and R connected to the first magnetic coil and the second magnetic coil, respectively.
2 is irradiated with laser light, and the magnetic coil to be operated is switched by utilizing the resistance change of each resistor. However, the invention is not limited to this, and the operation of the first magnetic coil and the second magnetic coil can be performed by laser light irradiation. It is also possible to use a switch such as an optical switch capable of switching.

[0058]

According to the magnetic head of the present invention, the magnetic core of the magnetic coil is irradiated with a pulsed laser beam to instantaneously heat the magnetic core to the Curie temperature or higher, thereby rapidly generating a magnetic field from the magnetic core. Because it can be switched
The magnetic field applied to the information recording medium can be switched at extremely high speed. A recording device having such a magnetic head can write information on a recording medium at an extremely high data transfer rate.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an example of an information recording medium on which information is recorded by a recording method of the present invention.

FIG. 2 is a schematic configuration diagram of a recording apparatus for carrying out the recording method of the present invention.

FIG. 3 is a conceptual diagram illustrating the configuration of the magnetic head according to the first embodiment of the present invention and the principle of high-speed switching when an external magnetic field is applied.

4 is a schematic diagram showing a specific example of the shape of a magnetic coil 4 of the magnetic head of FIG.

5 is an explanatory diagram for explaining the relationship between the laser light with which the magnetic core of the magnetic head of FIG. 3 is irradiated, the current flowing through the magnetic coil, and the temporal change of the external magnetic field generated from the magnetic head.

FIG. 6 is a conceptual diagram illustrating a configuration of a magnetic head according to a second embodiment of the present invention and a principle of high-speed switching for applying an external magnetic field.

7 is an explanatory diagram for explaining the relationship between the laser light with which the magnetic core of the magnetic head of FIG. 6 is irradiated, the current flowing through the magnetic coil, and the temporal change of the external magnetic field generated from the magnetic head.

8A and 8B are schematic diagrams of a magnetic head used in Example 3, FIG. 8A illustrates a case where a magnetic core is irradiated with laser light, and FIG. 8B illustrates a magnetic core including laser light. Is not irradiated.

9A and 9B are schematic views of a magnetic head used in Example 4, FIG. 9A shows a case where a magnetic core is irradiated with laser light, and FIG. Is not irradiated.

FIG. 10 is a schematic diagram of a magnetic head used in Example 5, FIG. 10 (a) shows a case where a resistor is irradiated with laser light, and FIG. 10 (b) shows a resistor with laser light. Is not irradiated.

11 is another configuration example of the recording apparatus shown in FIG.

FIG. 12 is a schematic diagram of a magnetic head using a permanent magnet as a magnetic field generation source for generating a magnetic field.

FIG. 13 is a graph showing how the magnetic moment disappears after laser light irradiation for 100 fs.

[Explanation of symbols]

1 substrate 2 backing layer 3 Magnetic layer 10 Information recording medium 21 signal source 22 Laser control device 23 Laser light source 25 magnetic coils 26 Objective Lens 28 mirror 200 recording device 30, 60, 80, 90, 100 Magnetic head

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroyuki Awano             Hitachima, 1-88, Torora, Ibaraki City, Osaka Prefecture             Within Kucsel Co., Ltd. F-term (reference) 5D075 AA03 CF03 CF04                 5D091 CC24 CC30 DD03 HH20

Claims (15)

[Claims] 1. A magnetic head for applying a magnetic field to a recording medium, comprising: a magnetic material; a magnetic field generating section for generating a magnetic field; heating means for heating the magnetic field generating section; A magnetic head. 2. The magnetic head according to claim 1, wherein the heating means heats the magnetic material forming the magnetic field generating portion to a Curie temperature or higher. 3. The magnetic head according to claim 1, further comprising a magnetic coil, wherein the magnetic field generating section is a magnetic core provided inside the magnetic coil. 4. The magnetic head according to claim 1, wherein the heating unit is a laser light source for irradiating the magnetic field generating unit with laser light. 5. The magnetic head according to claim 4, further comprising a laser control device that controls irradiation of the laser light according to recording information to control a magnetic field generated from a magnetic field generation unit. 6. The laser controller controls the laser light to be 1
The magnetic head according to claim 5, wherein pulse modulation is performed at a frequency of GHz or higher. 7. A light transmission section is further provided, the laser beam is irradiated onto the light transmission section, and the laser beam is irradiated onto the recording medium through the light transmission section. The magnetic head described. 8. The magnetic head according to claim 1, wherein the magnetic material contains a soft magnetic material. 9. The magnetic head according to claim 1, wherein an insulator is coated around the magnetic field generating portion. 10. The magnetic head according to claim 1, further comprising a heat dissipation member provided near the magnetic field generation unit. 11. The Curie temperature of the magnetic material is 80 ° C.
The magnetic head according to claim 1, wherein the magnetic head is in the range of ˜300 ° C. 11. 12. The magnetic head according to claim 4, further comprising a laser light source for irradiating the recording medium with laser light, in addition to the laser light source. 13. The magnetic coil includes two types of magnetic coils, a first magnetic coil and a second magnetic coil, and further includes a first switching device connected to the first magnetic coil; and a second magnetic coil. A second switching device which is operated; a first switch according to recorded information
A laser light source for simultaneously irradiating the switching device and the second switching device with laser light; and when the first switching device and the second switching device are irradiated with laser light, a magnetic field is generated only from the first magnetic coil. The magnetic head according to claim 3, wherein the magnetic field is generated only from the second magnetic coil when the first switch and the second switch are not irradiated with the laser light. 14. The magnetic head according to claim 13, wherein the first switching device and the second switching device are resistors having different resistance values. 15. A recording device comprising the magnetic head according to claim 1. Description: