JP4049196B2 - Optically assisted magnetic head and optically assisted magnetic disk device - Google Patents

Description

  The present invention relates to an optically assisted magnetic head and an optically assisted magnetic disk device, and more particularly to an optically assisted magnetic head and an optically assisted magnetic disk device that are capable of high-density recording and have improved light utilization efficiency and reliability.

  In recent years, the recording density of hard magnetic recording devices (HDD) has been increasing at an annual rate of 100%, and has exceeded 60 Gbpsi in the experimental stage. However, due to the superparamagnetic effect and the difficulty of narrowing the gap width of the magnetic head, the limit of the recording density of a conventional HDD is soon seen, and 100 to 300 Gbpsi is said to be the limit. In addition, optically assisted magnetic recording is expected to exceed that limit.

  Here, the superparamagnetic effect is a phenomenon in which recorded information is lost because the magnetization of the target magnetic domain is disturbed by the magnetic field formed by the adjacent magnetic domain. To prevent this, one means is to use a magnetic medium having a large magnetization, but recording cannot be performed with a normal magnetic head. As means for solving this, optically assisted magnetic recording has been proposed. In this method, recording is performed when the recording medium is heated to near the Curie temperature by laser irradiation and the magnetization thereof is lowered.

  In this optically assisted magnetic recording, only the portion heated by the laser beam is recorded. Therefore, by making the spot diameter of the laser beam small, it becomes possible to record a width narrower than the width of the magnetic gap. Suitable for increasing recording density. In order to achieve a recording density of 100 Gbps or more, the track width needs to be 0.1 μm or less. In order to obtain a light spot of this size, it is essential to use near-field light. As a conventional optically assisted magnetic recording / reproducing head using this method, for example, an optical waveguide integrated with a magnetic head is known (see Non-Patent Document 1).

FIG. 11 shows the conventional magneto-optical head. This optically assisted magnetic head 1 includes an optical waveguide 5, a magnetoresistive sensor using a magnetoresistive effect for reproduction, that is, a GMR (Giant-magnetoresistive) sensor 3, and a thin film magnetic transducer 4 on the rear end surface 2 a of the flying slider 2. The layers are laminated in order, and an optical waveguide lens is formed in the optical waveguide 5 to reduce the light spot at the waveguide exit end 5c, thereby aiming at higher density. In this method, the magnetic recording layer 6 a formed on the substrate 6 b of the magnetic disk 6 is heated by the near-field light 7 a emitted from the emission end 5 c of the optical waveguide 5, and then recorded by the leakage magnetic field of the thin film magnetic transducer 4. Is. Reference numeral 2b denotes an air bearing surface that flies over the magnetic recording layer 6a.
Tech-Dig. Optical Datastorage 2000, PD-23 (2000)

  However, according to the conventional optically assisted magnetic head, since the GMR sensor 3 is arranged between the optical waveguide 5 and the thin film magnetic transducer 4, the magnetic gap between the emission end 5c of the optical waveguide 5 and the thin film magnetic transducer 4 is reduced. Since the position is far away, the magnetic recording layer 6a of the magnetic disk is heated by the near-field light 7a emitted from the emission end 5c of the optical waveguide 5, and then recorded by the magnetic field in the magnetic gap portion of the thin film magnetic transducer 4 after a considerable delay. Therefore, there is a problem that the heating part is cooled by the thermal diffusion between them, and the utilization efficiency of the laser beam is deteriorated.

  In addition, since the thermal gradient becomes gentle, there is a problem that the recording part tends to spread. Furthermore, there is a problem that the GMR sensor 3 is easily heated by the laser light, the sensitivity of the GMR sensor 3 is affected by thermal fluctuation, and the reproduction output is unstable or the GMR sensor 3 that is relatively heat-sensitive deteriorates.

  In addition, this optically assisted magnetic head performs solid immersion type condensing with a lens in the optical waveguide. With this condensing method, a small light spot can be formed by the refractive index of the core. . However, it is at most about a half of the light spot diameter in the atmosphere, and even when a blue laser (wavelength 405 nm) is used, the limit is about 0.2 μm, and there is a limit to recording at high density.

  In addition, in this optically assisted magnetic head, it has not been proposed how to introduce laser light into the optical waveguide. Usually, the coupling efficiency between the laser and the optical waveguide is poor, and a large optical element is required to increase it, so special measures are required, and if the head height increases, the total volume increases. There is a problem that the recording density is lowered. For non-commutative disks such as HDDs, volume recording density is an important measure, and it is fatal to reduce this.

  Accordingly, it is an object of the present invention to provide an optically assisted magnetic head and an optically assisted magnetic disk apparatus capable of high-density recording and having improved light utilization efficiency and reliability.

In order to achieve the above object, the present invention provides a flying slider that floats by rotation of a disk having a recording medium, and a laser beam that is provided on the flying slider, introduces a laser beam from a semiconductor laser, and emits the recording medium from an emission end. an optical waveguide for heating the recording medium to emit near-field light, provided in the floating slider, having between a pair of pole tip of the magnetic circuit portion of the recording medium heated by the near-field light and a thin film magnetic transducer for recording information by a magnetic field formed in the magnetic gap, the magnetic gap is formed in the laser beam emitting position location of the exit end of the optical waveguide, wherein the magnetic circuit, the optical waveguide A pair of parallel yokes extending in parallel; an upper yoke connecting ends of the pair of parallel yokes away from the recording medium; and the pair of parallel yokes Providing light-assisted magnetic head is characterized in that a pair of lower yoke for connecting the pair of pole tip and the recording medium side of the end portion of the over click.
With this configuration, the distance between the position of the near-field light and the magnetic field formed by the thin film magnetic transducer is the shortest. Therefore, since recording is performed at the same time or immediately after heating by near-field light, the influence of thermal diffusion can be ignored, and the utilization efficiency of laser light can be improved. In addition, since the heating part does not spread due to thermal diffusion, the recording part can be narrowed and the density can be increased. Furthermore, since the heating of the magnetoresistive sensor can be reduced, the sensitivity of the magnetoresistive sensor is not affected by heat, and the reliability is high, the SN ratio is high, and a long life is possible.

To achieve the above object, the present invention provides an optically assisted magnetic disk apparatus for recording information by scanning an optically assisted magnetic head with a swing arm on a rotating disk having a recording medium. The head is provided on the flying slider that floats by the rotation of the disk and the flying slider, introduces laser light from a semiconductor laser, and emits near-field light from the emitting end to the recording medium. Information is recorded by a magnetic field formed in a magnetic gap provided between a pair of magnetic pole tips of a magnetic circuit on a portion of the recording medium that is provided on the floating waveguide and heated by the near-field light, and is provided on the flying slider. and a thin film magnetic transducer, said magnetic gap, is formed on the laser beam emitting position location of the exit end of the optical waveguide The magnetic circuit includes a pair of parallel yokes extending parallel to said optical waveguide, and an upper yoke which connects the ends remote from the recording medium of the pair of parallel yokes, the recording medium of the pair of parallel yokes An optically assisted magnetic disk apparatus comprising a pair of lower yokes connecting the end portions on the side and the pair of magnetic pole tip portions is provided.
With this configuration, it is possible to use an optically assisted magnetic head that is compact, lightweight, and capable of forming a minute light spot, and a high-density optically assisted magnetic disk device can be provided.

  According to the present invention, the distance between the position of the near-field light and the magnetic field formed by the thin film magnetic transducer is the shortest. Therefore, since recording is performed at the same time or immediately after heating by near-field light, the influence of thermal diffusion can be ignored, and the utilization efficiency of laser light can be improved. In addition, since the heating part does not spread due to thermal diffusion, the recording part can be narrowed and the density can be increased.

  1A to 1D show an optically assisted magnetic head according to a first embodiment of the present invention. (A) is a front view, (b) is a sectional view in the longitudinal direction of the optically assisted magnetic head in part A, and (c) is viewed from the direction of arrow R in FIG. (A). A side view and the same figure (d) are bottom views.

  As shown in FIG. 1A, the optically assisted magnetic head 1 has an optical waveguide 5, a magnetoresistive sensor 3, and a thin film magnetic transducer 4 integrated on the rear end surface 2a of the flying slider 2, and As shown in b), a metal film 11 in which a rectangular opening 11a for minimizing the size of near-field light formed at the emission end 5c of the optical waveguide 5 is disposed. This optically assisted magnetic head 1 floats on the magnetic recording layer 6a formed on the substrate 6b of the magnetic disk 6 by the air bearing surface 2b having the concave portion 2c of the flying slider 2 and moves relative to the magnetic recording layer 6a. Information is recorded / reproduced. In the present specification, in the longitudinal direction of the flying slider 2, the side closer to the flying slider 2 is referred to as the lower side and the far side is referred to as the upper side.

  Here, the magnetoresistive sensor 3 uses a normal GMR (Giant-magnetoresistive), and as shown in FIG. 5B, the spin valve film 30 and a pair of left and right electrodes 31a connected to the spin valve film 30. , 31b (however, in FIG. 5B, the electrode 31a is not visible because it is symmetrical to the electrode 31b), and the insulating film 32a formed on both sides of the spin valve film 30 and the electrodes 31a, 31b, 32b and a lower magnetic shield film 33 and an upper magnetic shield film 34 formed so as to sandwich the insulating films 32a and 32b, and the intensity of the magnetic field from the magnetic recording layer 6a crossing the spin valve film 30 is This is detected as a resistance change of the spin valve film 30. The upper magnetic shield film 34 also serves as the lower yoke of the thin film magnetic transducer 4.

  As shown in FIG. 2B, the thin film magnetic transducer 4 includes an upper yoke 40 including an upper magnetic pole 40a, a yoke portion 40b, and an upper yoke joint portion 40c, and includes a lower yoke joint portion 34b and an upper yoke joint portion 40c. By joining, a magnetic circuit 41 composed of the upper magnetic shield film 34 and the upper yoke 40 is formed, and a thin film coil 42 is wound so as to cross the magnetic circuit 41, and between the lower magnetic pole 34a and the upper magnetic pole 40a. A magnetic gap 43 is formed. In FIGS. 4B and 4D, 45a and 45b are insulating films.

  As shown in FIG. 5C, a lead part 42a and a pad 42b are formed at both ends of the thin film coil 42, respectively. The magnetic gap 43 is proportional to the current flowing through the thin film coil 42 supplied from the pad 42b. A magnetic field 44 is generated, and recording is performed on the magnetic recording layer 6 a by the magnetic field 44. When a ferrimagnetic material composed of a transition metal and a rare earth metal is used as a recording medium, the intensity of read magnetization can be increased by heating. In this case, the effect of heating by irradiation is used during reproduction. Therefore, the magnetoresistive sensor 3 is preferably formed on the rear side of the optically assisted magnetic head 1. Thereby, since the signal from only the heated portion of the recording layer 6a can be reproduced, not only the recording sensitivity can be increased, but also the crosstalk from the adjacent track during reproduction can be lowered.

  FIGS. 2A to 2E show details of the optical waveguide 5. The optical waveguide 5 is composed of a dielectric film 50 made of SiN and metal thin films 51 a and 51 b made of Ag arranged above and below the dielectric film 50.

The dielectric film 50 of the optical waveguide 5 shown in FIG. 2A is formed in parallel with a width of several microns from the incident end 5a, and has a tapered portion 5b tapered from a portion corresponding to the magnetic gap 43. The metal thin films 51a and 51b also have the same shape as the dielectric film 50, and have a 30 nm width at the tip. The thicknesses of the dielectric film 50 and the metal thin films 51a and 51b are 50 nm and 30 nm, respectively. Further, the shapes of the upper and lower metal thin films 51a and 51b may be asymmetric. As a result, the optical waveguide has the maximum intensity at the center, the excitation of the cut-off mode (HE ₁₁ mode) 7b can be suppressed, and the widths of the metal thin films 51a and 51b of the tapered portion 5b are reduced to the widths of the magnetic poles 34a and 40a. Therefore, the heating area of the magnetic recording layer 6 a by the optical waveguide 5 can be made narrower than the width of the magnetic gap 43.

  Here, as the material of the metal thin films 51a and 51b, a material having high conductivity such as Al is preferable in addition to Ag because it has high plasmon excitation efficiency, but is not limited thereto, and a magnetic pole material such as permalloy is also used. Is possible. In this case, only the metal film for the magnetic circuit can be used, and the metal film for the optical waveguide can be made unnecessary. However, in this case, it is necessary to reduce the diameter of the light spot at the exit end by forming a solid immersion lens in the optical waveguide. Further, the size of the near-field light can be further reduced by providing an opening, a slit, a metal scatterer, a gap formed by a plurality of metal scatterers, or the like smaller than the size of the near-field light.

  With this configuration, the laser beam incident from the incident end 5a of the optical waveguide 5 propagates through the optical waveguide 5, is collected by the tapered portion 5b, and emits the near-field light 7a from the emitting end 5c. At this time, the surface plasmon mode (HE mode) 7b having the maximum intensity at the interface is excited in the boundary between the metal thin films 51a and 51b and the dielectric film 50 in the optical waveguide 5 as shown in FIG. Is done. This mode is a mode that does not have a cut-off with respect to the cross-sectional size of the optical waveguide 5, and can efficiently propagate through the optical waveguide 5 even if the width and thickness of the optical waveguide 5 are reduced to a wavelength or less.

  The optical waveguide 5 is formed of a photonic crystal, so that a minute spot can be efficiently formed at the emission end 5c.

  An optical waveguide 5 shown in FIG. 2C is obtained by forming an optical waveguide metal thin film 51 b only on one side of the dielectric film 50. In this case, the near-field light 7 a can be brought closer by the magnetic gap 43. The near-field light 7a preferably has the maximum intensity on the metal thin film 51b side.

  In the optical waveguide 5 shown in FIG. 2D, the dielectric film 50 is formed in an L shape, and a plane mirror 53 is formed at a corner, and the laser light incident from the incident end 5a is bent by 90 degrees by the plane mirror 53. It is a thing. As a result, laser light can be incident from the side surface of the head 1, and the height of the head 1 can be reduced accordingly.

  An optical waveguide 5 shown in FIG. 2 (e) is formed by depositing an aspherical mirror 54 having a light collecting property instead of the flat mirror 53 shown in FIG. 2 (d). A parallel beam 7c from a semiconductor laser (not shown) is reflected by the aspherical mirror 54, and near-field light 7a is output from the focal point. Thereby, it can condense without the taper part 5b, and it becomes possible to raise light utilization efficiency.

  However, the spot diameter at the output end 5c formed by the above method is at most about one half of the wavelength, and in order to reduce the spot diameter to less than that, a small opening formed by a metal light shield, a donut-shaped opening, It is necessary to provide a metal scatterer or the like at the output position of the near-field light.

  FIGS. 3A to 3E show examples in which a minute metal body having a minute opening or a slit, a metal scatterer, and a plurality of metal scatterers are arranged at the emission end 5 c of the optical waveguide 5.

  FIG. 3A shows the metal film 11 in which a rectangular opening 11a is formed. By arranging the metal film 11 at the emission end 5 c of the optical waveguide 5, the size of the near-field light can be miniaturized. In this case, since the outgoing light can be increased by making the laser light incident so that the polarization direction 12 of the laser light is parallel to the short side of the rectangle, the size of the outgoing light can be significantly reduced, and thus the outgoing light Efficiency can be increased and recording density can be increased.

  In FIG. 3B, the metal piece 11b is arranged at the emission end 5c. Even such a metal piece can form near-field light.

  FIG. 3 (c) shows the trapezoidal metal films 11c and 11c with the upper bases facing each other. By arranging the polarization direction 12 of the convergent light that irradiates the two metal films 11c and 11c so as to cross the two metal films 11c and 11c, the phase of plasmons excited by the respective metal films 11c and 11c Since both of them work as dipole antennas, the near field generation efficiency can be further increased.

  FIG. 3D shows the same effect as FIG. 3C, although the arrangement of the metal film in FIG. 3C is shifted by 90 degrees.

  FIG. 3 (e) shows an elliptical metal film 11e, 11e having a minor axis that is one third of the major axis, with the major axis tips facing each other. Even an elliptical metal film whose minor axis is one third of the major axis can further improve the efficiency of plasmon excitation, and can further narrow the width of the generated plasmon.

  According to the optically assisted magnetic head of the first embodiment, a minute portion of the magnetic recording layer 6a can be heated by near-field light narrower than the width of the magnetic gap 43, and the coercive force is reduced by the heating. Only a portion can be recorded by the leakage magnetic field 44 from the magnetic poles 34a, 40a, high-density optically assisted magnetic recording is possible, and signal reproduction by the magnetoresistive sensor 3 is possible. As a general feature of optically assisted magnetic recording, it is possible to record on a magnetic recording film with a high coercive force, and since the influence of demagnetization due to the superparamagnetic effect is reduced, a head suitable for high density magnetic recording is provided. can do. Furthermore, the near-field light miniaturization means can be arranged at the output end 5c of the optical waveguide 5 to reduce the size of the output light, thereby increasing the output efficiency and increasing the recording density.

  FIG. 4 is a diagram showing an optically assisted magnetic head according to the second embodiment. In the magneto-optical head 1, in the first embodiment, a semiconductor laser (not shown) is arranged on the flying slider 2, and as a light introduction system to the optical waveguide 5, an optical fiber 9 and a reflecting film on the condensing surface 8a are provided. A combination with an aspherical mirror 8 made of glass on which 8b is deposited is used. That is, when a parallel beam 7c from a semiconductor laser (not shown) is incident on the core 9a of the optical fiber 9, the output light 7d of the optical fiber 9 is condensed on the incident end 5a of the optical waveguide 5 by the condensing surface 8a of the aspherical mirror 8. To do. Thus, when the single-mode optical fiber 9 is used, the diameter is 100 μm including the clad 9b, and the aspherical mirror 8 can be processed to the same size as that, thereby the flying slider 2 The height can be suppressed to about 30% higher than the height of about 300 μm. The near-field light miniaturization means is omitted.

  Further, a semiconductor laser (not shown), which is a light source for making laser light incident on the optical fiber 9, is disposed on the flying slider 2. Thereby, laser light can be incident from the side surface of the optically assisted magnetic head 1, and the size of the optically assisted magnetic head 1 can be reduced. The semiconductor laser may be mounted on a swing arm or suspension for supporting and scanning the optically assisted magnetic head 1. Thereby, the influence of the heat generated by the semiconductor laser on the magnetoresistive sensor 3 and the like can be avoided, high reliability can be maintained, the weight of the head can be reduced, and high-speed scanning can be performed.

  FIG. 5 shows an optically assisted magnetic head according to the third embodiment of the present invention. FIG. 4A is a front view, and FIG. 4B is a diagram showing an emission surface of the semiconductor laser. This optically assisted magnetic head 1 is configured by directly connecting a semiconductor laser 10 to an incident end 5 a of an optical waveguide 5 in the configuration shown in FIG. The size of the active layer 10a of the semiconductor laser 10 is about 2 × 0.1 μm, but the size of the oscillation mode inside the semiconductor laser 10 is widened to about 2 to 3 μm. On the other hand, since the size of the optical waveguide 5 is 3 × 0.11 μm, the metal film 11 having the opening 11a is disposed at the output position of the semiconductor laser 10 so as to match the size. By adjusting the position of the metal film 11 so that the reflected light to the inside of the semiconductor laser 10 and the oscillation mode inside the laser are in phase with each other by the metal film 11, the opening 11 a causes a loss to the semiconductor laser 10. In addition, by aligning the size of the opening 10a with the size of the optical waveguide 5 (3 × 0.11 μm), it is possible to make laser light incident into the optical waveguide 5 with minimum optical loss. Become. A metal film 11 having a minute opening 11a is disposed at the emission end 5c. With this configuration, the size of the output laser light can be further reduced, and recording on a recording medium can be performed at high density.

  According to the optically assisted magnetic head according to the third embodiment of the present invention, a minute portion of the magnetic recording layer 6a can be heated by near-field light narrower than the width of the magnetic gap, and the coercive force is reduced by the overheating. Only the lowered portion can be recorded by a leakage magnetic field in the vicinity of the upper magnetic pole, and high-density optically assisted magnetic recording becomes possible. In addition, as a general feature of optically assisted magnetic recording, it can be recorded on a magnetic recording film having a high coercive force, and the influence of demagnetization due to the superparamagnetic effect can be reduced, making it suitable for high-density magnetic recording. An optically assisted magnetic head can be provided.

  6A and 6B show an optically assisted magnetic head according to a fourth embodiment of the present invention. FIG. 6A is a front view, and FIG. The optically assisted magnetic head 1 has a configuration shown in FIG. 4 in which a semiconductor laser 10 is directly connected to an incident surface 8c of an aspherical mirror 8. Laser light emitted from the active layer 10 a of the semiconductor laser 10 is reflected by the aspherical mirror 8 and guided to the optical waveguide 5. A thin film magnetic transducer 4 and a magnetoresistive sensor 3 are sequentially formed on the optical waveguide 5. Further, a metal film 11 having a minute opening 11 a is disposed at the output end 5 c of the optical waveguide 5. With this configuration, the size of the output laser light can be further reduced, and recording on a recording medium can be performed at high density. Further, it is easy to manufacture and can be miniaturized.

  FIG. 7 shows an optically assisted magnetic head according to a fifth embodiment of the present invention. FIG. 7A is a sectional view showing the main part of the optically assisted magnetic head, and FIG. 7B is a laser beam output surface. The end view of the side, FIG. The optically assisted magnetic head 1 has an optical waveguide 5 and a thin film magnetic transducer 4 integrated on the surface of the optical waveguide 5.

In this embodiment, the optical waveguide 5 includes, for example, an SiO ₂ cladding layer 80 formed on the substrate 60, an SiN core layer 81 formed on the SiO ₂ cladding layer 80, and an SiN core layer 81. It comprises an SiO ₂ cladding layer 82 formed so as to cover it, and an SiO ₂ planarization buried layer 86 formed thereon.

  The thin film magnetic transducer 4 includes a core 24 made of a soft magnetic material such as permalloy, a yoke 27 and a magnetic pole portion 83, a magnetic circuit 41 having a magnetic gap 43 at the output end of the optical waveguide 5, and a core 24 of the magnetic circuit 41. The coil 25 (25a, 25b) wound around the coil 25, a pair of lead wires 28 extending from the coils 25a, 25b, respectively, and a pad 29 provided at the tip of the pair of lead wires 28, respectively. The coil part 21 which consists of Cu thin film arrange | positioned on the upper surface of this. The magnetic gap 43 and the pair of magnetic pole tip portions 84 constitute a gap portion 85.

Next, an example of a method for manufacturing the optically assisted magnetic head 1 will be described. After the optical waveguide 5 is formed on the substrate 60, planarization is performed with an insulating film 87 made of SiO ₂ or the like, and then the thin film magnetic transducer 4 is formed. That is, the lower coil 25a made of a Cu thin film is formed by sputtering and lithography by a normal thin film process, and further flattened and embedded by the insulating film 23, and the core 24, the upper coil 25b, and the yoke 27 made of Cu thin film are connected to the insulating film 26. It is embedded and formed. Thus, the coil part 21 is completed. Thereafter, the magnetic pole portion 83 and the magnetic gap 43 are formed on the waveguide exit end by sputtering and lithography, and the optically assisted magnetic head 1 of the present embodiment is completed. The magnetic pole portion 83 is fabricated so as to be embedded in an insulating film and have both surfaces in the same plane.

  Next, the operation of the fifth embodiment will be described. At the time of recording, the laser beam 10b and the magnetic field can be applied to the same location on the magnetic recording medium (not shown), so the temperature of the recording portion of the magnetic recording medium is increased by irradiation with the laser beam. So-called optically assisted magnetic recording is performed in which the coercive force is lowered and recording is performed with a modulated magnetic field. In the present embodiment, the size of the laser beam 10b is not particularly limited. By irradiation with the laser beam 10b, a recording area of the same size as the laser beam 10b is heated, and recording is performed by a magnetic field generated from the magnetic pole tip 84 located in the heating area. The size of the recording area is about the length of the magnetic pole tip 84 (hereinafter referred to as “gap width”) and the length of the magnetic gap 43 (hereinafter referred to as “gap length”). At the time of reproduction, information recorded on the recording medium is reproduced by converting a change in magnetic flux incident on the magnetic pole portion 83 into a current by the coil 25 when the magnetic gap 43 passes over the leakage magnetic field from the magnetic recording medium. .

  According to the above-described fifth embodiment, since the gap portion 85 of the thin film magnetic transducer 4 is disposed in the optical waveguide 5, a very small magneto-optical element can be provided. In addition, since the magnetic recording medium is heated and heated with near-field light, recording can be performed even on a medium having a high coercive force at room temperature, and the recording stability can be increased. In addition, near-field light can be irradiated to the recording mark during reproduction, so it is possible to increase the reproduction sensitivity by increasing the temperature by using a film such as TeFeCo whose magnetization is weak at room temperature and the magnetization increases by increasing the temperature. is there. In that case, the semiconductor laser may be continuously turned on, or may be turned on in pulses in synchronization with the recording mark position. In the former case, since the synchronization is unnecessary, the lighting circuit can be simplified. In the latter case, the energy efficiency of the laser beam can be increased, and the heating of the emitting portion can be prevented. In addition, the distance from the coil 25 to the magnetic gap 43 can be reduced to about 10 μm or less, and the width of the magnetic pole portion 83 can be increased, so that the magnetic resistance can be lowered. In addition, since the coil 25 is wound around the core 24 in a cylindrical shape, the coil length can be shortened as compared with the case where the coil 25 is wound in a disk shape, so that the electrical resistance can be reduced. Therefore, these enable high-speed and high-density recording.

  FIG. 8 shows the exit end of the optical waveguide of the optically assisted magnetic head according to the sixth embodiment of the present invention. This optically assisted magnetic head 1 is formed by forming a light shield 22 having an opening 90 at the exit end of an optical waveguide and forming a magnetic gap 43 on the light shield 22. Au can be used, but metal materials such as Ag and Al may be used.

  The light shield 22 may be formed so as to be flush with the magnetic pole part 83 and surround the magnetic pole part 83. Thereby, since an opening and the magnetic gap 43 are formed on the same plane, each processing precision can be raised.

  8A to 8F show modified examples of the opening 90 and the gap 43. FIG. FIG. 8A shows an example in which the size of the opening 90 is made slightly larger than the magnetic gap 43, and the opening 90 is widely formed mainly on the recording upstream side A of the magnetic gap 43. For this reason, the output of the laser beam can be made relatively large, and since the magnetic recording medium is heated immediately before the magnetic field in the magnetic gap 43 is applied and the temperature is raised, recording can be performed efficiently.

  FIG. 8B shows an example in which a trapezoidal upper base is made to face the tip of the pole portion 83 and the gap width is narrowed. This makes it possible to make the temperature rising portion of the magnetic recording medium narrower than the gap width. In the magnetic pole tip 84, the magnetic field usually spreads in the peripheral portion, and the recording magnetic field is suppressed by the leakage magnetic field, and it is difficult to narrow the recording track width. However, according to this example, the near field determined by the gap 43 interval. Since the recording width is suppressed by the light, higher density recording is possible. Further, a gap is formed in a direction parallel to the recording track of the recording medium, and recording can be performed while erasing previously recorded marks, thereby enabling high-density recording. Further, when the gap is arranged so as to be rotated by 90 degrees, the gap is formed in the direction perpendicular to the recording track of the recording medium, and the recording width is suppressed by the near-field light determined by the gap 43, so that High-density recording is possible.

  FIG. 8C shows an example in which a minute metal body 91 smaller than the size of the opening 90 is formed in the opening 90. By forming the opening 90 coaxially with respect to the minute metal body 91 in this manner, propagating light can be emitted even when the size of the opening 90 is as small as 1/10 of the wavelength of the laser, and the intensity of the laser light is increased. Can do. Further, the near-field light can be scattered by the center minute metal body 91 or the near-field light emitted from the plasmon excited in the minute metal body 91 can be used for raising the temperature of the recording medium, and also has a higher intensity. It becomes possible to use the laser beam.

  FIG. 8D shows an example in which a pair of magnetic pole tips 84 and 84 are formed so as to oppose each other, whereby the magnetic gap 43 and the magnetic pole tips 84 can be processed more finely, and the magnetic field application range is narrowed. be able to. The opening 90 may be formed large so as to include the magnetic gap 43 or may be formed inside the magnetic gap 43. As a result, the recording range can be further narrowed, and the density can be increased.

  8E and 8F, an opening 90 is provided in the vicinity of one of the pair of magnetic pole tips 84, 84, and only the magnetic recording medium in the vicinity of the magnetic pole tip 84 is heated and heated, and the other magnetic pole tip is heated. The temperature rise around the portion 84 is suppressed as much as possible. The magnetic field in the gap perpendicular direction (perpendicular to the paper surface) under the magnetic gap 43 is maximum at each magnetic pole tip 84, and the magnetic field directions at each magnetic pole tip 84 are opposite to each other. Therefore, with this configuration, only a part of the recording medium through which one direction of the magnetic field passes can be heated, optically assisted magnetic recording in a minute region is possible, and the density can be further increased. In this configuration, since the magnetic field uses only a portion perpendicular to the recording medium, a substantially unipolar magnetic pole is formed, which is particularly suitable for recording on a perpendicular magnetic recording medium. Is possible.

  According to the sixth embodiment described above, the same effects as those of the fifth embodiment can be obtained, and the size of the laser beam 10b is about 90, so that the heating region can be miniaturized, and the recording medium Heating other than the recording portion can be reduced. Further, except for FIG. 8B, the laser light in the portion other than the opening 90 is reflected by the light shield 22 and returns to the laser and contributes to laser oscillation, so that the light utilization efficiency can be improved. In addition, since the recording area can be limited by superimposing both the opening 90 and the magnetic gap 43, a finer recording mark can be formed than in the case where each of the openings 90 and the magnetic gap 43 is independently performed, and the density can be increased. In addition, since only the portion where the perpendicular magnetic field exists can be recorded by superimposing both the opening 90 and the magnetic gap 43, a magneto-optical head suitable for recording on a perpendicular magnetic medium can be configured.

  FIG. 9 shows an optically assisted magnetic head according to the seventh embodiment of the present invention. In the seventh embodiment, a light shield 22 having an opening 90 at the exit end of the optical waveguide, a magnetic circuit (not shown) having two magnetic gaps 43a and 43b on the opening 90 of the light shield 22, A coil portion (not shown) that independently detects a change in magnetic flux incident on the two magnetic gaps 43a and 43b.

  FIG. 9A has a common magnetic pole portion 83a located at the center and individual magnetic pole portions 83b located on both sides thereof, with the magnetic pole tips 84a at the center being in common, and magnetic gaps 43a and 43b on the left and right. And a magnetic pole tip 84b is formed. The coil part has two coils independently, but the core center part is connected to the common magnetic pole part 83a, and the structure is simplified. The light shield 22 has a single opening 90, and the laser light output from the single opening 90 irradiates both magnetic gaps 43a and 43b simultaneously. With this configuration, two gap portions capable of independently modulating the magnetic field are formed close to each other, so that recording / reproduction is performed simultaneously on two adjacent recording tracks (not shown) using this element. And the transfer rate of recording and reproduction can be doubled. Note that the number of magnetic gaps is not limited to two, and can be increased depending on the application. The magnetic gap may be formed on the surface emitting semiconductor laser. At this time, the light shield 22 may also serve as an electrode.

  FIG. 9B is a modification of FIG. 9A, in which two openings 90a and 90b are formed diagonally on the light shield 22, and magnetic gaps 43a and 43b are formed above the two openings 90a and 90b. It is arranged. Thereby, the recording area can be defined by the sizes of the openings 90a and 90b, and the recording area can be miniaturized and densified.

  FIG. 9C is another modification of FIG. 9A, in which two openings 90 a and 90 b are formed so as to face the light shielding body 22, and two openings are formed by four individual magnetic pole portions 84. Magnetic gaps 43a and 43b are arranged above 90a and 90b. Thereby, the freedom degree of a structure of a magnetic circuit can be increased. Further, since the two cores (not shown) are arranged opposite to each other, this is a modification particularly suitable for application to a surface emitting semiconductor laser.

  FIG. 10 shows a magneto-optical disk apparatus according to the eighth embodiment of the present invention. The magneto-optical disk device 100 is a magnetic disk 101 having a perpendicular magnetic recording layer 103 such as Pt / Cr, a motor 102 for rotating the magnetic disk 101, and flying vertically on the perpendicular magnetic recording layer 103 so as to be perpendicular. The same optically assisted magnetic head 104 as in the first to seventh embodiments for recording / reproducing on / from the magnetic recording layer 103, a swing arm 105 that supports the optically assisted magnetic head 104, and a scan for scanning the swing arm 105 A voice coil motor 106 and a signal processing circuit 107 that processes a recording signal at the time of recording, modulates a laser beam of the optically assisted magnetic head 104, and reproduces recorded information by using a light intensity signal from the optically assisted magnetic head 104 at the time of reproduction. And a control circuit 108 for controlling the motor 102 and the voice coil motor 106 during recording / reproduction. That. As the optically assisted magnetic head 104, for example, the one of the first embodiment can be used.

  The semiconductor laser is disposed on the swing arm 105 or the suspender 109. The semiconductor laser is optically connected to an optical fiber that guides the laser beam. The suspender 109 has a spring force that gives a constant flying height in balance with the weight of the head 104 and the flying force.

  In this configuration, during recording, laser light whose intensity is modulated based on signal input is emitted from the semiconductor laser, and the near-field light emitted from the emission end 5c of the optical waveguide 5 is miniaturized by the near-field light miniaturization means. Then, the light is incident on the perpendicular magnetic recording layer 103 disposed immediately below it to heat the recording layer 103, and information is recorded by the magnetic field 44 flowing between the magnetic poles 40a and 34a. At the time of reproduction, the strength of the magnetic field from the magnetic recording layer 103 is detected by the magnetoresistive sensor 3 (see FIG. 1). At the time of recording / reproducing, it is necessary to move the light emitted from the head 104 onto a specific recording track (not shown) on the recording layer 103 and to track it. This is performed by position control by driving the voice coil motor 106. That is, the address information of the magnetic disk 101 is read, and the voice coil motor 106 is driven by the drive signal formed based on the information to move the head 104 near a predetermined track. By driving the scanning semiconductor laser, a predetermined track is made to follow finely.

  According to the eighth embodiment, a small and light magneto-optical head can be used for recording / reproducing of a magnetic disk, and high-speed recording / reproducing, high density, particularly high volume recording density, optically assisted magnetic recording. It is possible to provide a disc device that can be played back. Since the head itself is small and light, the entire head may be driven by a piezoelectric element (not shown) for fine tracking.

1A is a front view, FIG. 2B is a cross-sectional view in the longitudinal direction of the optically assisted magnetic head in part A, and FIG. The side view seen from the arrow R direction, (d) is a bottom view. . (A)-(e) is a figure which shows the optical waveguide which concerns on the 1st Embodiment of this invention. (A)-(e) is a figure which shows the output end of the optical waveguide which concerns on the 1st Embodiment of this invention. It is a figure which shows the optically assisted magnetic head which concerns on the 2nd Embodiment of this invention. (A) is a front view, (b) is a figure which shows the emitting surface of a semiconductor laser regarding the optically assisted magnetic head concerning the 3rd Embodiment of this invention. (A) is a front view, (b) is a principal part detail drawing regarding the optically assisted magnetic head concerning the 4th Embodiment of this invention. The optically assisted magnetic head according to the fifth embodiment of the present invention includes (a) a cross-sectional view showing the main part of the optically assisted magnetic head, (b) an end view on the laser beam output surface side, and (c) It is a top view. (A)-(f) is a figure which shows the laser emission end of the optically assisted magnetic head based on the 6th Embodiment of this invention. (A), (b), (c) is a figure which shows the laser emission end of the optically assisted magnetic head based on the 7th Embodiment of this invention. It is a figure which shows the magneto-optical disc apparatus based on the 8th Embodiment of this invention. It is a figure which shows the conventional magneto-optical head.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical assist magnetic head 2 Flying slider 2a Rear end surface 2b Air bearing surface 2c Recess 3 Magnetoresistance sensor 4 Thin film magnetic transducer 5 Optical waveguide 5a Incident end 5b Tapered portion 5c Emission end 6 Magnetic disk 6a Recording layer 6b Substrate 7a Near field light 7b Mode 7c Parallel beam 7d Output light 8 Aspherical mirror 8a Condensing surface 8b Reflective film 8c Incident surface 9 Optical fiber 9a Core 9b Clad 10 Semiconductor laser 10a Active layer 10b Laser light 11, 11c, 11e Metal film 11a Opening 11b Metal piece 12 Polarization direction 13 Aperture 14 Micro metal body 21 Coil portion 22 Light shield 22 and 23 Insulating film 24 Core 25 Coil 25a Lower coil 25b Upper coil 26 Insulating film 27 Yoke 28 Lead wire 29 Pad 30 Spin valve films 31a and 31b Electrodes 32a and 32b Insulating film 33 Lower magnet Air shield film 34 Upper magnetic shield film 34a Lower magnetic pole 34b Lower yoke joint 40 Upper yoke 40a Upper magnetic pole 40b Yoke 40c Upper yoke joint 41 Magnetic circuit 42 Thin film coil 42a Lead part 42b Pads 43, 43a, 43b Magnetic gap 44 Magnetic field 50 Dielectric films 51a, 51b Metal thin film 53 Flat mirror 54 Aspherical mirror 60 Substrate 80 Clad layer 81 Core layer 82 Clad layer 83 Magnetic pole part 83a Common magnetic pole part 83b Individual magnetic pole part 84, 84a, 84b Magnetic pole tip part 85 Gap part 86 SiO ₂ planarizing buried layer 87 insulating film 90, 90a, 90b opening 91 minute metallic member 100 magneto-optical disk drive 101 a magnetic disk 102 motor 103 perpendicular magnetic recording layer 104 light-assisted magnetic head 105 swing arm 106 voice coil motor 107 signal processing circuit 108 control circuit 109 suspender

Claims (11)

A flying slider that floats by rotating a disk having a recording medium;
An optical waveguide that is provided on the flying slider, introduces laser light from a semiconductor laser, emits near-field light from the emitting end to the recording medium, and heats the recording medium;
A thin film magnetic transducer which is provided on the flying slider and records information by a magnetic field formed in a magnetic gap between a pair of magnetic pole tips of a magnetic circuit in a portion of the recording medium heated by the near-field light ,
The magnetic gap is formed in the laser beam emitting position location of the exit end of the optical waveguide,
The magnetic circuit includes a pair of yokes extending in parallel with the optical waveguide, a core connecting ends of the pair of yokes away from the recording medium, and ends of the pair of yokes on the recording medium side. An optically assisted magnetic head comprising a pair of magnetic pole portions connecting the pair of magnetic pole tip portions .   The optically assisted magnetic head according to claim 1, wherein the magnetic gap is formed in a direction crossing a recording track of the recording medium.   2. The optically assisted magnetic head according to claim 1, wherein the magnetic gap is formed in a direction parallel to a recording track of the recording medium.   2. The optically assisted magnetic head according to claim 1, wherein the thin film magnetic transducer and a magnetoresistive sensor for detecting a recording signal of the recording medium are sequentially formed on the optical waveguide.   2. The optically assisted magnetic head according to claim 1, wherein the magnetoresistive sensor and the thin film magnetic transducer are sequentially formed on the optical waveguide.   The semiconductor laser is provided on the flying slider so as to emit laser light in parallel with the recording medium, and the optical waveguide includes a mirror that reflects the laser light from the semiconductor laser and emits the laser light from the emission end. The optically assisted magnetic head according to claim 1, wherein the optically assisted magnetic head is provided.   The semiconductor laser is provided in the flying slider so as to emit laser light in parallel to the recording medium, and the optical waveguide intersects the light guide path for guiding the laser light from the semiconductor laser, and the light guide path. And an optical waveguide provided at the intersection of the light guide and the optical waveguide, and a mirror that reflects the laser light guided by the light guide and emits it from the exit end. The optically assisted magnetic head according to claim 1. The optically assisted magnetic head according to claim 7 , wherein the light guide path is an optical fiber.   2. The optically assisted magnetic head according to claim 1, wherein the semiconductor laser is provided with a minute metal body having a minute opening on an emission surface.   2. The light according to claim 1, wherein the magnetic pole tip that forms the magnetic gap miniaturizes near-field light formed at the emission end of the optical waveguide by the laser light from the semiconductor laser. Assist magnetic head. In an optically assisted magnetic disk device for recording information by scanning an optically assisted magnetic head with a swing arm on a rotating disk having a recording medium,
The optically assisted magnetic head is
A flying slider that floats by rotating the disk;
An optical waveguide that is provided on the flying slider, introduces laser light from a semiconductor laser, emits near-field light from the emitting end to the recording medium, and heats the recording medium;
A thin film magnetic transducer which is provided on the flying slider and records information by a magnetic field formed in a magnetic gap between a pair of magnetic pole tips of a magnetic circuit in a portion of the recording medium heated by the near-field light ,
The magnetic gap is formed in the laser beam emitting position location of the exit end of the optical waveguide,
The magnetic circuit includes a pair of yokes extending in parallel with the optical waveguide, a core connecting ends of the pair of yokes away from the recording medium, and ends of the pair of yokes on the recording medium side. An optically assisted magnetic disk apparatus comprising: a pair of magnetic pole portions connecting the pair of magnetic pole tip portions .

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