JP2006209960A - Magnetic recording-and-reproducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic recording-and-reproducing device which can highly precisely perform tracking even if a pitch between tracks is narrowed. <P>SOLUTION: The magnetic recording-and-reproducing device is provided with; a magnetic recording medium 2 comprising a substrate 21, beltlike magnetic recording parts 22 which are provided on the one main face of the substrate and are arranged in parallel to one another, and a beltlike nonmagnetic parts 23 which exist between the beltlike magnetic recording parts; a recording-and-reproducing head 7 comprising an electron beam radiation part 18 which is located facing one of the beltlike magnetic recording parts 22 and radiates the beltlike magnetic recording part 22 with the electron beam, a magnetic field generation part 14 which is located facing the beltlike magnetic recording part 22 that faces the electron beam radiation part 18, a magnetism detection part 15 which is located facing the beltlike magnetic recording part 22 that faces the electron beam radiation part 18; an ammeter 19 which is connected to the electron beam radiation part 18 and detects an amount of currents flowing from the electron beam radiation part 18 to the beltlike magnetic recording part 22 facing the electron beam radiation part 18; and a driving mechanism which relatively moves the magnetic recording medium 2 and the recording-and-reproducing head 7 along the beltlike magnetic recording part 22 facing the electron beam radiation part 18. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a magnetic recording / reproducing apparatus, and more particularly, to a magnetic recording / reproducing apparatus using a heat-assisted magnetic recording technique.

  The functions of information devices such as personal computers have been dramatically improved, and the amount of information handled by users has also increased significantly. Therefore, expectation for an information recording / reproducing apparatus having a remarkably higher recording density than ever is increasing.

  In order to increase the recording density on the information recording medium, it is necessary to reduce the size of the recording mark. However, at present, a great difficulty is encountered in reducing the size of the recording mark. Hereinafter, a magnetic recording / reproducing apparatus such as a hard disk apparatus will be described as an example.

  In general, a magnetic recording medium mounted on a magnetic recording / reproducing apparatus uses a polycrystalline body having a wide particle size distribution in a recording layer. That is, the recording layer of a general magnetic recording medium contains polycrystals having various particle diameters ranging from those having a large particle diameter to those having a small particle diameter.

  However, a polycrystalline body having an excessively small size has a large thermal fluctuation. Therefore, when the recording mark is made smaller, the number of polycrystals contained in one recording mark is reduced and the interaction between the recording marks is relatively increased, so that the recording stability is lowered. In addition, noise increases.

  Such a problem can be prevented by aligning the polycrystals constituting the recording layer to a size sufficient to suppress thermal fluctuation. However, in that case, a very strong magnetic field is required for writing information, and as a result, writing information to the recording layer becomes impossible.

  As a technique that enables information to be written in such a recording layer with a relatively weak magnetic field, a heat-assisted magnetic recording technique that utilizes the fact that the coercive force of a magnetic recording layer is reduced by heating is known. In order to realize high-density recording with this heat-assisted magnetic recording technique, it is advantageous to reduce the heating spot, and means for irradiating near-field light and electron beam are considered as the means.

  However, heat-assisted magnetic recording technology requires strict thermal design. In addition, in order to increase the recording density with the heat-assisted magnetic recording technology, it is also necessary to reduce the pitch between tracks. In this case, the influence of heat conduction between adjacent tracks increases, and in particular, the crossing due to heating increases. Erase becomes prominent. In addition, when the pitch between tracks is narrowed, tracking becomes difficult, and it may be impossible to write servo signals by a servo writer and read servo signals by a magnetic head.

  In order to solve such a problem, Patent Document 1 discloses a belt-like nonmagnetic portion in which a magnetic recording layer is patterned into a belt shape corresponding to a track to form a belt-like magnetic recording portion and adjacent tracks are interposed therebetween. Discloses a magnetically separated discrete medium. According to such a medium, the cross-erase due to heating can be suppressed because the belt-like nonmagnetic portion is interposed between the adjacent tracks.

  Further, if the structure disclosed in Patent Document 1 is adopted, the arrangement of the band-shaped magnetic recording portion and the band-shaped nonmagnetic portion can be used for tracking, so that the servo signal writing by the servo writer is unnecessary. Become. In other words, if two optical sensors are provided in the recording / reproducing head so as to face the boundary between the belt-like magnetic recording portion to which information is to be written and the two belt-like nonmagnetic portions adjacent to both sides thereof, heat-assisted magnetic recording Tracking can be performed by detecting the reflected light of the near-field light irradiated to the belt-shaped magnetic recording unit with these optical sensors.

However, in such a structure, since the amount of reflected light that can be received is insufficient, high tracking accuracy cannot be realized when the pitch between tracks is narrowed. Further, the recording / reproducing head described above is difficult to manufacture.
JP 2000-195002 A

  The present invention has been made in view of the above problems, and an object thereof is to provide a magnetic recording / reproducing apparatus capable of performing tracking with high accuracy even when the pitch between tracks is narrowed.

It is another object of the present invention to provide a magnetic recording / reproducing apparatus that can be easily designed.
It is another object of the present invention to provide a magnetic recording / reproducing apparatus capable of preventing the occurrence of cross erase even when the pitch between tracks is narrowed.

  According to one aspect of the present invention, a substrate, a plurality of strip-shaped magnetic recording units provided on one main surface of the substrate and arranged in parallel to each other, and a plurality of strip-shaped nonmagnetic members interposed between the plurality of strip-shaped magnetic recording units, respectively. A magnetic recording medium, an electron beam emitting unit that emits an electron beam toward one of the plurality of band-shaped magnetic recording units and emits an electron beam toward the band-shaped magnetic recording unit, and a band shape that the electron beam emitting unit faces A recording / reproducing head comprising a magnetic field generating unit facing the magnetic recording unit and a magnetic detection unit facing the strip-shaped magnetic recording unit facing the electron beam emitting unit, and the electron beam emitting unit connected to the electron beam emitting unit An ammeter for detecting the amount of current flowing from the electron beam emitting unit to the band-shaped magnetic recording unit opposed to the electron beam emitting unit, and the magnetic recording medium and the recording / reproducing along the band-shaped magnetic recording unit opposed to the electron beam emitting unit Drive that moves relative to the head Magnetic recording and reproducing apparatus characterized by comprising a mechanism is provided.

  Further, according to the reference example of the present invention, a substrate, a plurality of strip-shaped magnetic recording units provided on one main surface of the substrate and arranged in parallel with each other, and a plurality of strip-shaped media interposed between the plurality of strip-shaped magnetic recording units, respectively. A magnetic recording medium including a non-magnetic portion; a near-field light emitting portion that faces one of the plurality of strip-shaped magnetic recording portions and emits near-field light toward the strip-shaped magnetic recording portion; and the near-field light emission A magnetic field generating unit opposed to the band-shaped magnetic recording unit opposed to the band, a magnetic detection unit opposed to the band-shaped magnetic recording unit opposed to the near-field light emitting unit, and the near-field light among the plurality of band-shaped magnetic recording units A first optical sensor having a light receiving portion opposed to one located on one side with respect to a strip-shaped magnetic recording portion opposed to the emitting portion, and the near-field light emitting portion of the plurality of strip-shaped magnetic recording portions opposed to each other Located on the other side of the belt-shaped magnetic recording section A recording / reproducing head comprising a second optical sensor having a light-receiving part facing the object, and the magnetic recording medium and the recording / reproducing head relative to each other along a belt-like magnetic recording part opposed to the near-field light emitting part. Provided is a magnetic recording / reproducing apparatus including a drive mechanism for movement.

  The magnetic recording / reproducing apparatus according to the reference example of the present invention can further include a control unit connected to the first optical sensor, the second optical sensor, and the driving mechanism. When such a control unit is provided, a plurality of relative positions of the recording / reproducing head with respect to the magnetic recording medium are set based on the first signal from the first optical sensor and the second signal from the second optical sensor. The operation of the drive mechanism can be controlled so as to change in the direction of arrangement of the belt-like magnetic recording portions. This control is performed, for example, by comparing the first signal from the first photosensor with the second signal from the second photosensor and the difference between the magnitude of the first signal and the magnitude of the second signal. Can be made smaller.

  The magnetic recording / reproducing apparatus according to one aspect of the present invention can further include a control unit connected to the ammeter and the drive mechanism. When such a control unit is provided, the operation of the drive mechanism is controlled based on the signal from the ammeter so that the relative position of the recording / reproducing head with respect to the magnetic recording medium is changed in the arrangement direction of the plurality of strip-shaped magnetic recording units. can do. This control can be performed, for example, such that fluctuations in the magnitude of the signal from the ammeter are suppressed.

  In the present invention, since a magnetic recording medium having a structure in which adjacent strip-shaped magnetic recording portions are separated by strip-shaped nonmagnetic portions can be used, cross-erase can be sufficiently prevented even when the pitch between tracks is narrowed, Moreover, the thermal design is easy. Furthermore, in the present invention, an ammeter is provided so that an electron beam used for heat-assisted magnetic recording can be used for tracking, so that tracking can be performed with high accuracy even when the pitch between tracks is narrowed. Become.

  That is, according to the present invention, a magnetic recording / reproducing apparatus capable of performing tracking with high precision even when the pitch between tracks is narrowed is provided. In addition, according to the present invention, a magnetic recording / reproducing apparatus with easy thermal design is provided. Furthermore, according to the present invention, there is provided a magnetic recording / reproducing apparatus capable of preventing the occurrence of cross erase even when the pitch between tracks is narrowed.

  Hereinafter, the present invention will be described in more detail with reference to the drawings. In addition, in each figure, the same referential mark is attached | subjected to the same or similar component, and the overlapping description is abbreviate | omitted.

  FIG. 1 is a perspective view schematically showing a magnetic recording / reproducing apparatus according to an embodiment and a reference example of the present invention. The magnetic recording / reproducing apparatus 1 shown in FIG. 1 has a magnetic disk 2 as a magnetic recording medium. The magnetic recording / reproducing apparatus 1 uses a heat-assisted magnetic recording technique for writing information on a magnetic disk 2. As the magnetic disk 2, a discrete magnetic recording medium (discrete magnetic disk) described later is used. Yes.

  The magnetic disk 2 is rotatably supported by a spindle 3, and a motor (not shown) that operates in response to a control signal from a control circuit (not shown) is connected to the spindle 3. In the magnetic recording / reproducing apparatus 1 shown in FIG. 1, this makes it possible to control the rotation of the magnetic disk 2 and the like.

  A fixed shaft 4 is disposed in the vicinity of the circumferential portion of the magnetic disk 2, and the fixed shaft 4 swings the magnetic head assembly 5 via ball bearings (not shown) disposed at two locations above and below the fixed shaft 4. I support it as possible. A coil (not shown) is wound around the bobbin portion of the magnetic head assembly 5, and this coil, a permanent magnet disposed opposite to the coil, and a counter yoke form a magnetic circuit and a voice. A coil motor 6 is configured. This voice coil motor 6 is also connected to the control circuit, so that the head slider 7 at the tip of the magnetic head assembly 5 can be positioned on a desired track of the magnetic disk 2.

  The magnetic head assembly 5 includes, for example, an actuator arm 8 including a bobbin portion that holds a drive coil. One end of a suspension 9 is attached to the actuator arm 8, and a head slider 7 is attached to the other end of the suspension 9. The head slider 7 incorporates a recording / reproducing head described later.

  Lead wires (not shown) for signal writing and reading are formed on the suspension 9, and these lead wires are electrically connected to the electrodes of the recording / reproducing head incorporated in the head slider 7, respectively. Yes. In the magnetic recording / reproducing apparatus 1, information is recorded and reproduced while the magnetic disk 2 is rotated and the head slider 7 is floated from the magnetic disk 2. In the magnetic recording / reproducing apparatus 1 shown in FIG. 1, the control circuit and the like constitute a control unit, and the motor connected to the spindle 3 and the voice coil motor 6 constitute a drive mechanism.

  The structure of the head slider 7 is mainly different between the embodiment of the present invention and the reference example. Hereinafter, differences between the embodiment and the reference example will be mainly described.

  FIG. 2 is a plan view schematically showing the head slider 7 used in the magnetic recording / reproducing apparatus 1 according to the reference example of the present invention. The head slider 7 shown in FIG. 2 has a support body 11, and one end portion of the support body 11 constitutes a slider section 12. On one main surface of the other end of the support 11, a near-field light emitting unit 13 such as a fine hole, a magnetic field generating unit 14, and a magnetic detection unit 15 of a magnetic sensor are provided so as to be arranged in a straight line. Furthermore, light receiving portions 16a and 16b of a pair of photosensors are provided at positions symmetrical to the straight line so as to sandwich the near-field light emitting portion 13 therebetween. The head slider 7 configured as described above is arranged with respect to the magnetic disk 2 as shown in FIGS. 3 and 4, for example.

  FIG. 3 is a sectional view schematically showing a magnetic recording / reproducing apparatus 1 according to a reference example of the present invention. In FIG. 3, components unnecessary for understanding are omitted in order to facilitate understanding of the relative positions of the head slider 7 and the magnetic disk 2, and the head is used to explain the cross-sectional structure of the head slider 7. The slider 7 is drawn by rotating the direction by 90 °. In FIG. 3, reference numeral 17 denotes a light source such as a surface emitting laser. Light from the light source 17 passes through the near-field light emitting unit 13 and is directed toward the magnetic disk 2 as near-field light. Emitted. In this reference example, this near-field light is used for tracking control performed at the time of recording and reproduction, in addition to being used for heating a band-shaped magnetic recording unit described later when performing heat-assisted magnetic recording.

  As shown in FIG. 3, the head slider 7 is arranged so that the surface on which the near-field light emitting portion 13 and the like are provided faces the magnetic disk 2. When the head slider 7 is arranged in this manner, the head slider 7 can be floated from the magnetic disk 2 by an air flow generated by driving the motor 10 and rotating the magnetic disk 2 supported by the spindle 3.

  FIG. 4 is a plan view schematically showing a magnetic recording / reproducing apparatus 1 according to a reference example of the present invention. In FIG. 4, in order to facilitate understanding of the relative position between the head slider 7 and the magnetic disk 2, components unnecessary for understanding are omitted, and the head slider 7 is depicted as a perspective view.

  As shown in FIG. 4, the magnetic disk 2 has a structure in which a plurality of strip-shaped magnetic recording portions 22 and a plurality of strip-shaped nonmagnetic portions 23 are alternately arranged on one main surface of a substrate 21. Such a magnetic disk 2 is called a discrete magnetic recording medium.

  Each of the strip-shaped magnetic recording units 22 is formed of a magnetic recording film, and the distance between adjacent strip-shaped magnetic recording units 22 is constant. This magnetic recording film can be made of a magnetic recording material similar to that used for ordinary magnetic recording films.

  The band-shaped magnetic recording unit 22 has a spiral shape or a concentric shape when viewed from a direction perpendicular to the main surface of the substrate 21. In addition, when the strip | belt-shaped magnetic recording part 22 has a concentric circular shape, these strip | belt-shaped magnetic recording parts 22 form several circles mutually spaced apart. On the other hand, when the strip-shaped magnetic recording unit 22 has a spiral shape, the strip-shaped magnetic recording units 22 are connected to each other to form one strip.

  The strip-shaped nonmagnetic portion 23 is provided so as to be interposed between the strip-shaped magnetic recording portions 22. Accordingly, when the belt-like magnetic recording portion 22 has a concentric shape when viewed from the direction perpendicular to the main surface of the substrate 21, the belt-like nonmagnetic portion 23 forms a plurality of circles separated from each other. When the strip-shaped magnetic recording portion 22 has a spiral shape, the strip-shaped nonmagnetic portions 23 are connected to each other to form one strip.

  The strip-shaped nonmagnetic portion 23 plays a role of magnetically separating the strip-shaped magnetic recording portions 22 adjacent to each other in the vertical direction in the figure. Moreover, the strip | belt-shaped nonmagnetic part 23 can prevent a cross erase and can make thermal design easy by selecting the material which comprises it suitably.

The belt-like nonmagnetic portion 23 is usually made of a nonmagnetic thin film or a groove. If the strip the non-magnetic portion 23 is composed of a non-magnetic thin film, the material is not particularly limited as long as the non-magnetic material, for example, a dielectric such as non-magnetic metal or SiO ₂ and Al ₂ O ₃ such as gold Can be used. Further, when the belt-like nonmagnetic portion 23 is a groove, the magnetic recording film does not have to exist inside the groove. If the groove is not completely embedded, the bottom surface and the side wall of the groove are covered with the magnetic recording film. It may be broken.

  When the magnetic recording / reproducing apparatus 1 configured as described above writes information and reads the written information, the near-field light emitting unit 13, the magnetic field generating unit 14, and the magnetic detection unit 15 are any of the strip-shaped magnetic recordings. By rotating the magnetic disk 2 while aligning the head slider 7 in the direction indicated by the double arrow 26 so as to be positioned on the portion 22 (or track), the belt-like magnetic recording portion 22 and the belt-like nonmagnetic portion 23 are moved. Move in the direction indicated by arrow 25. In this reference example, a pair of optical sensors 16a and 16b are used for such alignment, that is, tracking.

  That is, the reflected light of the near-field light irradiated to the magnetic disk 2 from the near-field light emitting unit 13 is received by the light receiving units 16a and 16b, and detected by a pair of optical sensors having the light receiving units 16a and 16b. Usually, since the reflectance is different between the strip-shaped magnetic recording portion 22 and the strip-shaped non-magnetic portion 23, the center position of the near-field light emitting portion 13 and the center position of the strip-shaped magnetic recording portion 22 opposite to the center position are shifted. The signals from these optical sensors are not the same. In other words, the signal from the optical sensor having the light receiving unit 16a and the signal from the optical sensor having the light receiving unit 16b are the same only when the center positions match. Therefore, tracking control can be performed by appropriately moving the head slider 7 in the direction indicated by the double arrow 26 so that the signals from these optical sensors are the same.

  In general, the distance between the magnetic disk 2 and the recording / reproducing head 7 is about 10 to 30 nm. This is much shorter than the wavelength of light used for thermally assisted magnetic recording. For this reason, the near-field light emitted from the near-field light emitting unit 13 of the recording / reproducing head 7 to the band-shaped magnetic recording unit 22 does not become propagating light even if reflected by the band-shaped magnetic recording unit 22, and is not near-field. The space between the magnetic disk 2 and the recording / reproducing head 7 is filled with light. In particular, when the surface of the support 11 facing the magnetic disk 2 or the belt-like nonmagnetic portion 23 is made of a metal material, the reflected light reaches the end of the head 7 as near-field light due to surface plasmon. become. Thus, the reflected light reaching the end of the head 7 can also be used for the tracking control.

  In the magnetic recording / reproducing apparatus 1 according to the present reference example, the light receiving portions 16a and 16b of the pair of optical sensors in the state where the tracking control is performed are the same as the band-shaped magnetic recording portion 22 that the near-field light emitting portion 13 faces. Opposite to the strip-shaped magnetic recording portions 22 located on both sides. Therefore, unlike the case where the light receiving portions 16a and 16b are opposed to both boundary portions of the strip-shaped magnetic recording portion 22 opposed to the near-field light emitting portion 13, the size and arrangement flexibility of the light receiving portions 16a and 16b are large. Therefore, as shown in FIG. 4, the light receiving portions 16 a and 16 b of the pair of optical sensors can be opposed to the plurality of strip-shaped magnetic recording portions 22 in a state where tracking control is performed.

  In this case, the size of each of the light receiving portions 16a and 16b of these optical sensors is at least larger than the sum of the width of the belt-like magnetic recording portion 22 and the width of the belt-like nonmagnetic portion 23. In other words, in the magnetic recording / reproducing apparatus 1 shown in FIG. 4, each of the light receiving portions 16a and 16b of the optical sensor has a size sufficient to efficiently collect the reflected light. Therefore, according to the magnetic recording / reproducing apparatus 1 according to the present reference example, even when the pitch between tracks is narrowed, the deviation of the relative position of the recording / reproducing head 7 in the direction indicated by the double-headed arrow 26 with respect to the magnetic disk 2 is quickly corrected. Can do. That is, in the magnetic recording / reproducing apparatus 1 according to this reference example, even when the pitch between tracks is narrowed, tracking can be performed with high accuracy, and therefore, a high CNR (Carrier to Noise Ratio) can be realized. It is.

  In the prior art, as described above, the recording / reproducing head is opposed to the boundary between the strip-shaped magnetic recording section facing the near-field light emitting section and the two strip-shaped nonmagnetic sections adjacent to both sides thereof. Two optical sensors had to be provided. That is, in the prior art, it is necessary to form the respective light receiving portions of the two photosensors in a very small size and extremely shorten the distance between the light receiving portions. For this reason, it has been difficult to manufacture the recording / reproducing head with the prior art.

  On the other hand, in the magnetic recording / reproducing apparatus 1 according to the reference example, the size of the light receiving portions 16a and 16b of the optical sensor can be increased, and the light receiving portions 16a and 16b do not need to be as close as those of the prior art. Therefore, the recording / reproducing head 7 according to this reference example can be easily manufactured.

  In this reference example, when the belt-like nonmagnetic portion 23 is a groove, the groove depth is set so that the difference between the light reflectance of the belt-like magnetic recording portion 22 and the light reflectance of the belt-like nonmagnetic portion 23 is sufficiently large. It is preferable to set. In this reference example, when the belt-like nonmagnetic portion 23 is formed of a nonmagnetic thin film, the difference between the light reflectance of the belt-like magnetic recording portion 22 and the light reflectance of the belt-like nonmagnetic portion 23 is sufficiently large. It is preferable to select the material for the strip-shaped magnetic recording portion 22 and the material for the strip-shaped nonmagnetic portion 23. As the difference in light reflectance is larger, tracking control can be more easily performed and tracking accuracy can be improved. Normally, the material of the strip-shaped magnetic recording unit 22 tends to be limited to a material having a low reflectance. Since various materials can be used for the strip-shaped nonmagnetic portion 23 from a high reflectance to a low reflectance, if a material having a high reflectance is selected as the material of the strip-shaped nonmagnetic portion 23, the above-described reflectance difference is reduced. It can be easily realized.

  In the reference example described above, as shown in FIG. 4, the light receiving portions 16 a and 16 b of the optical sensor are opposed to the two strip-shaped magnetic recording portions 22 adjacent to the strip-shaped magnetic recording portion 22 facing the near-field light emitting portion 13. However, the arrangement of the light receiving portions 16a and 16b of the optical sensor is not limited to this. For example, between the strip-shaped magnetic recording unit 22 facing the near-field light emitting unit 13 and the plurality of strip-shaped magnetic recording units 22 facing the light-receiving unit 16 a and the strip-shaped magnetic recording unit 22 facing the near-field light emitting unit 13. And one or more strip-shaped magnetic recording units 22 may be interposed between the strip-shaped magnetic recording units 22 facing the light receiving unit 16b. In this case, although the light collection efficiency at the light receiving portions 16a and 16b is slightly reduced, the distance between the light receiving portions 16a and 16b of the optical sensors and the near-field light emitting portion 13 as a heat source can be increased. The influence of fluctuation is reduced. Therefore, the tracking accuracy can be further improved, that is, a higher CNR can be realized.

  In FIG. 4, for the sake of simplification, each of the light receiving portions 16a and 16b of the optical sensor is depicted in a size that can be opposed to the two strip-shaped magnetic recording portions 22, but there are more light receiving portions 16a and 16b. It is desirable to have a size that can be opposed to the belt-like magnetic recording unit 22. In general, each of the light receiving portions 16a and 16b of the optical sensor preferably has a size that can be opposed to 2 to 1000 strip-shaped magnetic recording portions 22, and 10 to 200 strip-shaped magnetic recording portions 22 are opposed to each other. More preferably, it has a possible size.

Next, an embodiment of the present invention will be described.
FIG. 5 is a plan view schematically showing the head slider 7 used in the magnetic recording / reproducing apparatus 1 according to the embodiment of the present invention. The head slider 7 shown in FIG. 5 has a support 11, and one end of the support 11 constitutes a slider portion 12. On one main surface of the other end portion of the support 11, an electron beam emitting unit 18, a magnetic field generating unit 14, and a magnetic detection unit 15 of a magnetic sensor are provided so as to be arranged in a straight line. The head slider 7 configured as described above is arranged with respect to the magnetic disk 2 as shown in FIGS. 6 and 7, for example.

  FIG. 6 is a cross-sectional view schematically showing the magnetic recording / reproducing apparatus 1 according to one embodiment of the present invention. FIG. 7 is a plan view schematically showing the magnetic recording / reproducing apparatus 1 according to one embodiment of the present invention. In FIGS. 6 and 7, components that are not necessary for understanding are omitted in order to facilitate understanding of the relative positions of the head slider 7 and the magnetic disk 2, and in FIG. In order to explain the cross-sectional structure, the head slider 7 is depicted as a perspective view in FIG. In FIG. 6, reference numeral 19 indicates an ammeter that measures the amount of electron beam irradiated from the electron beam emitting portion 18 onto the magnetic disk 2. In the present embodiment, this electron beam is used for tracking control performed during recording and reproduction, in addition to being used for heating the band-shaped magnetic recording unit 22 when performing heat-assisted magnetic recording.

  In the magnetic recording / reproducing apparatus 1 configured as described above, an ammeter 19 is used to perform tracking control. That is, in this embodiment, the amount of the electron beam irradiated to the magnetic disk 2 from the electron beam emitting unit 18 is detected by the ammeter 19. Usually, since the electric resistance is different between the band-shaped magnetic recording unit 22 and the band-shaped nonmagnetic unit 23, the signal from the ammeter 19 is sent to the center position of the electron beam emitting unit 18 and the center of the band-shaped magnetic recording unit 22 facing it. It changes according to the degree of deviation from the position. Therefore, by appropriately moving the head slider 7 in the direction indicated by the double arrow 26 based on the change in the signal from the ammeter 19, tracking can be performed with high accuracy, that is, high CNR can be realized.

  In the magnetic recording / reproducing apparatus 1 according to the present embodiment, the electron beam from the electron beam emitting unit 18 is used for both heat-assisted magnetic recording and tracking control. Therefore, the structure of the recording / reproducing head 7 according to the present embodiment is simplified, and therefore can be easily manufactured.

  In the present embodiment, it is preferable that the electrical resistance of the strip-shaped nonmagnetic portion 23 is larger than the electrical resistance of the strip-shaped magnetic recording portion 22. In this case, tracking can be performed with higher accuracy, that is, higher CNR can be realized.

  In the magnetic recording / reproducing apparatus 1 according to the embodiment and the reference example described above, the magnetic sensor having the magnetic detection unit 15 is preferably a planar type GMR element. When a planar GMR element is used as the magnetic sensor, the surface of the wafer on which the planar GMR element is formed is opposed to the magnetic disk 2. Therefore, when the recording / reproducing head 7 is provided with an optical sensor having the near-field light emitting portion 13 and the light receiving portions 16a and 16b, they can also be formed on the wafer on which the magnetic sensor is formed. It becomes easy.

The magnetic disk 2 used in the embodiment and the reference example described above can be manufactured, for example, by the following method.
First, as used in the manufacture of an optical disk, a substrate 21 having a concavo-convex structure such as a land / groove is formed on the surface by polymer injection molding using a mold. Alternatively, when the substrate 21 having a flat surface is used, a resin thin film such as a resist film is formed on the flat surface, and the mold is pressed against the thin film to transfer the concavo-convex structure, whereby the surface of the substrate 21 is transferred. A concavo-convex structure like a land / groove is formed. Next, a magnetic recording film is formed on the surface of the substrate 21 provided with the concavo-convex structure by using a normal vapor deposition method such as a sputtering method. According to such a method, the magnetic recording film is formed so as to cover not only the convex portion of the substrate surface but also the bottom and side walls of the concave portion. However, since the concavo-convex structure on the surface of the substrate is usually transferred also to the magnetic recording film, the magnetic disk 2 in which the strip-shaped magnetic recording portion 22 and the strip-shaped nonmagnetic portion 23 are provided on the substrate 21 by such a method is used. Obtainable.

  The magnetic disk 2 can be manufactured by other methods. That is, first, a substrate 21 having a flat surface is prepared. Next, a magnetic recording film is formed on the entire flat surface of the substrate 21. Next, a resist film or the like is formed on the magnetic recording film, and a mold is pressed against the resist film to transfer the concavo-convex structure. That is, a resist pattern is formed. Thereafter, the magnetic recording film is etched using the resist pattern as a mask, whereby the magnetic disk 2 in which the belt-like magnetic recording portion 22 and the belt-like nonmagnetic portion 23 are provided on the substrate 21 can be obtained.

  All of the above-described methods for manufacturing the magnetic disk 2 are suitable for mass production, and the width of the belt-like magnetic recording unit 22 can be reduced. The magnetic disk 2 can also be manufactured by methods other than these. For example, a method using optical lithography, electron beam lithography, or a method using a scanning probe such as an operation tunnel microscope or a near-field light microscope can be used. According to the method using optical lithography, it is relatively difficult to reduce the width of the belt-like magnetic recording unit 22, but high productivity can be realized. Further, according to the method using electron beam lithography or a scanning probe, it is difficult to achieve high productivity, but the width of the strip-shaped magnetic recording unit 22 can be reduced. These techniques can also be used for manufacturing the above-described mold, that is, the master.

  In the embodiment and the reference example described above, the recording / reproducing head 7 is moved in the direction of the double arrow 26 when performing the tracking control. However, the moving direction of the recording / reproducing head 7 is limited to the direction indicated by the double arrow 26. is not. That is, the moving direction of the recording / reproducing head 7 is not particularly limited as long as it is a direction intersecting the arrow 25.

  In the embodiment and the reference example, the band-shaped magnetic recording unit 22 is moved in the direction indicated by the arrow 25 during recording and reproduction. However, the band-shaped magnetic recording unit 22 is moved to the arrow 25 with respect to the recording / reproducing head 7. If it can be moved relative to the direction shown, only the band-shaped magnetic recording unit 22 may be moved, only the recording / reproducing head 7 may be moved, or both the band-shaped magnetic recording unit 22 and the recording / reproducing head 7 may be moved. It may be moved. Similarly, in the embodiment and the reference example, when performing the tracking control, the recording / reproducing head 7 is moved in the direction of the double arrow 26, but the recording / reproducing head 7 is moved with respect to the belt-like magnetic recording unit 22 by the double arrow 26. If only the recording / reproducing head 7 can be moved, only the band-shaped magnetic recording unit 22 may be moved, or both the band-shaped magnetic recording unit 22 and the recording / reproducing head 7 may be moved. May be moved.

  Further, in the above embodiment and the reference example, the case where the magnetic recording medium 2 is a magnetic disk and the belt-like magnetic recording portion 22 and the belt-like nonmagnetic portion 23 are spiral or concentric has been described. Other forms may be used. For example, the magnetic recording medium 2 may be a card. In this case, the belt-like magnetic recording portion 22 and the belt-like nonmagnetic portion 23 are preferably linear.

Examples of the present invention will be described below.
(Reference example)
In this example, as will be described in detail below, the magnetic recording / reproducing apparatus 1 shown in FIGS. 3 and 4 was manufactured, and the tracking accuracy was examined.

  That is, in this example, the surface emitting laser 17 having a wavelength of 650 nm was used, the size of the near-field light emitting unit 13 was 70 nm long × 100 nm wide, and the size of the single pole writing unit 14 was 80 nm long × 20 nm wide. The size of the readout unit 15 of the planar GMR element is 80 nm in length × 20 nm in width, and the size of the light receiving units 16a and 16b of the C-MOS photosensor is 10 μm in diameter. The distance between the near-field light emitting unit 13 and the writing unit 14 was 100 nm, and the distance between the writing unit 14 and the reading unit 15 was 200 nm. The distance between the near-field light emitting part 13 and each of the light receiving parts 16a and 16b was 400 nm. Here, “longitudinal” means a direction along the longitudinal direction of the strip-shaped magnetic recording unit 22, and “horizontal” means a direction perpendicular thereto. In this example, the head slider 7 configured as described above is supported by a two-stage actuator having a piezoelectric element.

In this example, a magnetic disk 2 produced by the following method was used. That is, first, a Pd underlayer (not shown) having a thickness of 30 nm, a TbFeCo film having a thickness of 50 nm, and a SiO ₂ film having a thickness of 50 nm are formed on a glass substrate having a diameter of 2.5 inches (= 6.35 cm). Films were sequentially formed. TbFeCo is a perpendicular magnetic recording material for thermally assisted recording.

Next, a resist was spin-coated on the SiO ₂ film to form a resist film. Next, the mold was pressed against the resist film, and the uneven pattern was transferred to the resist film. That is, a resist pattern was formed. Note that the mold used here is a Ni mold manufactured by using an electron beam lithography technique and a plating method, and the contact surface with the resist film has a spiral of 40 nm in width, 50 nm in height, and 70 nm in spacing. A convex portion is provided.

Next, the exposed portion of the SiO ₂ film was removed by reactive ion etching (RIE) using the resist pattern as an etching mask to form a spiral recess having a bottom surface made of a TbFeCo film. Further, the exposed portion of the TbFeCo film and the SiO ₂ film were removed by performing Ar ion milling using the SiO ₂ film as a mask. As described above, a belt-like magnetic recording unit 22 composed of a spiral TbFeCo film was obtained.

  Thereafter, an Al film having a thickness of 50 nm was formed on the entire surface of the substrate 21 on which the strip-shaped magnetic recording portion 22 was formed, and the spiral recess formed by the strip-shaped magnetic recording portion 22 was filled with Al. Next, this Al film was polished by a chemical mechanical polishing method (CMP method) until the upper surface of the strip-shaped magnetic recording portion 22 was exposed. As a result, a strip-like nonmagnetic portion 23 composed of a spiral Al film was obtained. Further, a diamond-like carbon protective film was formed on the strip-shaped magnetic recording portion 22 and the strip-shaped nonmagnetic portion 23. As described above, the magnetic disk 2 was obtained.

  The magnetic disk 2 thus obtained was observed with a magnetic force microscope. As a result, it was possible to confirm a structure in which a portion adjacent to the width direction of the strip-shaped magnetic recording portion 22 having a width of 70 nm was separated by the strip-shaped nonmagnetic portion 23 having a width of 40 nm.

  With respect to the magnetic recording / reproducing apparatus 1 configured as described above, the tracking accuracy at the time of reading was examined by setting the irradiation power of the surface emitting laser 17 to 1 mW. As a result, tracking could be performed with sufficiently high accuracy even at a reading speed of 400 Mbps. Further, with respect to the magnetic recording / reproducing apparatus 1, the tracking accuracy at the time of writing was examined with the irradiation power of the surface emitting laser 17 set to 5 mW. As a result, tracking could be performed with sufficiently high accuracy even at a writing speed of 100 Mbps. Also, the frequency of cross erase was sufficiently suppressed to 0.001% or less.

(Comparative example)
A magnetic recording / reproducing apparatus having substantially the same configuration as that described in the reference example was manufactured except that a magnetic disk manufactured by the method described below was used. That is, in this comparative example, a magnetic disk was used in which a Pd underlayer having a thickness of 30 nm and a TbFeCo film having a thickness of 50 nm were sequentially formed on a glass substrate having a diameter of 2.5 inches (= 6.35 cm). Since the magnetic disk thus obtained is not a discrete medium, it is impossible to perform tracking by the same method as used in the reference example. Therefore, in this comparative example, a servo signal was recorded on the magnetic recording film using a servo writer, and tracking was performed using a GMR read head.

  However, in the magnetic recording / reproducing apparatus according to this comparative example, the reading speed is limited to 150 Mbps. When the writing speed was 100 Mbps, cross erase was observed at a frequency of 0.3%.

(Example)
In this embodiment, as will be described in detail below, the magnetic recording / reproducing apparatus 1 shown in FIGS. 6 and 7 was manufactured, and the tracking accuracy was examined.

  That is, in this embodiment, the electron beam emitting portion 18 has a diameter of 50 nm, and the single magnetic pole writing portion 14 has a length of 80 nm × width of 20 nm. The size of the readout portion 15 of the planar type GMR element was 80 nm long × 20 nm wide. The distance between the electron beam emitting unit 18 and the writing unit 14 was 80 nm, and the distance between the writing unit 14 and the reading unit 15 was 200 nm. Here, “longitudinal” means a direction along the longitudinal direction of the strip-shaped magnetic recording unit 22, and “horizontal” means a direction perpendicular thereto. In this embodiment, the head slider 7 configured as described above is supported by a two-stage actuator having a piezoelectric element.

In this example, the magnetic disk 2 produced by the following method was used. That is, first, a Pd underlayer (not shown) having a thickness of 30 nm, a TbFeCo film having a thickness of 50 nm, and a SiO ₂ film having a thickness of 50 nm are formed on a glass substrate having a diameter of 2.5 inches (= 6.35 cm). Films were sequentially formed. TbFeCo is a perpendicular magnetic recording material for thermally assisted recording.

  Next, a resist was spin-coated on the TbFeCo film to form a resist film. Next, the mold was pressed against the resist film, and the uneven pattern was transferred to the resist film. That is, a resist pattern was formed. Note that the mold used here is a Ni mold manufactured by using an electron beam lithography technique and a plating method, and the contact surface with the resist film has a spiral of 40 nm in width, 50 nm in height, and 70 nm in spacing. A convex portion is provided.

Next, the exposed portion of the SiO ₂ film was removed by reactive ion etching (RIE) using the resist pattern as an etching mask to form a spiral recess having a bottom surface made of a TbFeCo film. Further, the exposed portion of the TbFeCo film and the SiO ₂ film were removed by performing Ar ion milling using the SiO ₂ film as a mask. As described above, a conductive belt-like magnetic recording unit 22 composed of a spiral TbFeCo film was obtained.

Thereafter, an electrically insulating SiO ₂ film having a thickness of 50 nm is formed on the entire surface of the substrate 21 on which the band-shaped magnetic recording portion 22 is formed, and the spiral recess formed by the band-shaped magnetic recording portion 22 is made of SiO ₂ . Embedded. Next, this SiO ₂ film was polished by a chemical mechanical polishing method (CMP method) until the upper surface of the strip-shaped magnetic recording portion 22 was exposed. As a result, an electrically insulating strip-like nonmagnetic portion 23 formed of a spiral SiO ₂ film was obtained. Further, a diamond-like carbon protective film was formed on the strip-shaped magnetic recording portion 22 and the strip-shaped nonmagnetic portion 23. As described above, the magnetic disk 2 was obtained.

  The magnetic disk 2 thus obtained was observed with a magnetic force microscope. As a result, it was possible to confirm a structure in which a portion adjacent to the width direction of the strip-shaped magnetic recording portion 22 having a width of 70 nm was separated by the strip-shaped nonmagnetic portion 23 having a width of 40 nm.

  Regarding the magnetic recording / reproducing apparatus 1 configured as described above, the tracking accuracy at the time of reading was examined. Note that the tracking at the time of reading was performed by controlling the position of the recording / reproducing head 7 so that the amount of current detected by the ammeter 19 was substantially constant at 1 μA. As a result, tracking could be performed with sufficiently high accuracy even at a reading speed of 500 Mbps.

  Further, with respect to the magnetic recording / reproducing apparatus 1, the tracking accuracy during writing was examined. At the time of writing, tracking was performed by increasing the irradiation amount of the electron beam and controlling the position of the recording / reproducing head 7 so that the amount of current detected by the ammeter 19 was substantially constant at 30 μA. As a result, tracking could be performed with sufficiently high accuracy even at a writing speed of 200 Mbps. Also, the frequency of cross erase was sufficiently suppressed to 0.001% or less.

1 is a perspective view schematically showing a magnetic recording / reproducing apparatus according to an embodiment and a reference example of the present invention. The top view which shows schematically the head slider used with the magnetic recording / reproducing apparatus which concerns on the reference example of this invention. Sectional drawing which shows schematically the magnetic recording / reproducing apparatus which concerns on the reference example of this invention. 1 is a plan view schematically showing a magnetic recording / reproducing apparatus according to a reference example of the present invention. 1 is a plan view schematically showing a head slider used in a magnetic recording / reproducing apparatus according to an embodiment of the present invention. The figure which shows schematically the manufacturing apparatus of the display apparatus which concerns on one Embodiment of this invention. 1 is a plan view schematically showing a magnetic recording / reproducing apparatus according to an embodiment of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Magnetic recording / reproducing apparatus, 2 ... Magnetic disk, 3 ... Spindle, 4 ... Fixed shaft, 5 ... Magnetic head assembly, 6 ... Voice coil motor, 7 ... Head slider, 8 ... Actuator arm, 9 ... Suspension, 10 ... Motor DESCRIPTION OF SYMBOLS 11 ... Support body 12 ... Slider part 13 ... Near field light emission part 14 ... Magnetic field generation part 15 ... Magnetic detection part 16a ... Light reception part 16b ... Light reception part 17 ... Light source 18 ... Electron beam emission , 19 ... ammeter, 21 ... substrate, 22 ... strip-shaped magnetic recording section, 23 ... strip-shaped nonmagnetic section, 25 ... arrow, 26 ... double arrow.

Claims (3)

A magnetic recording medium comprising a substrate, a plurality of strip-shaped magnetic recording portions provided on one main surface of the substrate and arranged in parallel with each other, and a plurality of strip-shaped nonmagnetic portions interposed between the plurality of strip-shaped magnetic recording portions, respectively ,
An electron beam emitting portion that emits an electron beam toward one of the plurality of band-shaped magnetic recording portions and emits an electron beam toward the band-shaped magnetic recording portion, and a magnetic field generating portion that faces the band-shaped magnetic recording portion that faces the electron beam emitting portion A recording / reproducing head comprising: a magnetic detecting unit opposed to the belt-shaped magnetic recording unit opposed to the electron beam emitting unit;
An ammeter that detects the amount of current that is connected to the electron beam emitting unit and flows from the electron beam emitting unit toward the band-shaped magnetic recording unit that is opposed to the electron beam emitting unit, and the band-shaped magnet that is opposed to the electron beam emitting unit. A magnetic recording / reproducing apparatus comprising a drive mechanism for moving the magnetic recording medium and the recording / reproducing head relative to each other along a recording unit.   The controller further includes a control unit connected to the ammeter and the drive mechanism, and the control unit changes a relative position of the recording / reproducing head with respect to the magnetic recording medium in an arrangement direction of the plurality of strip-shaped magnetic recording units. The magnetic recording / reproducing apparatus according to claim 1, wherein the operation of the drive mechanism is controlled by the control based on a signal from the ammeter.   The magnetic recording / reproducing apparatus according to claim 2, wherein the control unit controls the operation of the drive mechanism so that a variation in the magnitude of a signal from the ammeter is suppressed.

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