JP2011204345A - Near-field light assisted magnetic recording head and information recording/reproduction device including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a near-field light assisted magnetic recording head which has excellent mass productivity and provides high-density recording, and an information recording/reproduction device including the same.SOLUTION: A near-field light generation element, a main magnetic pole, a sub-magnetic pole, and a light guide structure are all formed on a substrate. A base portion of the near-field light generation element is made of a material which generates surface plasmon when irradiated with propagating light guided from the light guide structure. The near-field light generation element transmits energy from the base portion to a tip portion and generates near-field light from the tip portion. The tip portion of the near-field light generation element is positioned between the main magnetic pole and the sub-magnetic pole.

Description

  The present invention relates to a near-field light assisted magnetic recording head that records various information on a magnetic recording medium at high density using thermal assistance by near-field light, and an information recording / reproducing apparatus including the same.

  In recent years, the recording density of information within a single recording surface has increased as the capacity of hard disks and the like in computer equipment has increased. For example, in order to increase the recording capacity per unit area of the magnetic disk, it is necessary to increase the surface recording density. However, as the recording density increases, the recording area occupied by one bit on the recording medium decreases. When this bit size is reduced, the energy of 1-bit information becomes close to the thermal energy at room temperature, and the recorded information is reversed or disappears due to thermal fluctuations, etc. Will occur.

  In the in-plane recording method that has been generally used, the magnetism is recorded so that the direction of magnetization is in the in-plane direction of the recording medium. In this method, the recorded information is lost due to the thermal demagnetization described above. Is likely to occur. Therefore, in order to solve such a problem, a shift is being made to a perpendicular recording method in which a magnetization signal is recorded in a direction perpendicular to the recording medium. This method is a method for recording magnetic information on the principle of bringing a single magnetic pole closer to a recording medium. According to this method, the recording magnetic field is directed substantially perpendicular to the recording film. Information recorded by a perpendicular magnetic field is easy to maintain in energy stability because it is difficult for the N pole and the S pole to form a loop in the recording film surface. Therefore, this perpendicular recording method is more resistant to thermal demagnetization than the in-plane recording method.

  However, recent recording media are required to have a higher density in response to the need to record and reproduce a larger amount and higher density information. For this reason, in order to minimize the influence of adjacent magnetic domains and thermal fluctuations, those having a strong coercive force have begun to be adopted as recording media. For this reason, it is difficult to record information on a recording medium even in the above-described perpendicular recording system.

  In order to solve such problems, there is a hybrid magnetic recording method (near-field light assisted magnetic recording method) in which the magnetic domain is locally heated by near-field light to temporarily reduce the coercive force, and writing is performed during that time. Proposed. This hybrid magnetic recording system is a system that uses near-field light generated by the interaction between a minute region and an optical aperture formed in a size equal to or smaller than the wavelength of light formed in the near-field optical head. In this way, by using a small optical aperture exceeding the diffraction limit of light, that is, a near-field light head having a near-field light generating element, a heat source having a size much smaller than the wavelength of light is obtained. be able to.

  Note that the near-field light generating element is not limited to the above-described optical micro-aperture, and may be constituted by, for example, a protrusion formed in a nanometer size. This projection can also generate near-field light in the same manner as the optical minute aperture. In addition, by propagating light energy in a form localized on the metal surface via surface plasmon polariton that combines light and electronic vibration of the metal surface, energy is transmitted to a region much smaller than the wavelength of light. Can concentrate. By this mechanism, a heat source having a minute size can be obtained, and near-field light assisted magnetic recording that reduces the coercive force by heating a minute region on the surface of the recording medium becomes possible.

  Various structures have been proposed for the near-field light assisted magnetic recording head. In Patent Document 1, elements are arranged in the order of a sub magnetic pole, a main magnetic pole, and a near-field light generating element on the bottom surface of a slider head that floats on air, and light from a light source arranged at a place other than the head is also sent to a place other than the head. The light is condensed by a lens disposed on the head and irradiated to the near-field light generating element of the head. The near-field light generating element is a metal film having a substantially triangular shape, and excites surface plasmons by light irradiation. Since the tip of the triangle coincides with the bottom surface of the head, strongly localized energy is radiated from the bottom surface of the head to heat a minute region on the surface of the recording medium. The coercive force decreases in the heated microregion. There is a main magnetic pole adjacent to the near-field light generating element. This main magnetic pole generates a magnetic field, and magnetic recording is performed by magnetizing the above-described minute region where the coercive force is reduced.

  As a structure of the near-field light assisted magnetic recording head, there is a structure disclosed in Patent Document 2 in addition to the above-described structure. In the head structure disclosed in Patent Document 2, elements are arranged in the order of a near-field light generating element, a main magnetic pole, and a sub magnetic pole on the bottom surface of a slider head that floats on air, and light from a light source arranged at a place other than the head is used. After being introduced into the head by an optical fiber, the propagation direction is changed by a curved mirror portion and is incident on a waveguide inside the head. A minute region is heated on the medium surface by near-field light generated at the waveguide tip, and the region is magnetized by a magnetic field generated from the main magnetic pole.

JP 2004-158067 A (FIG. 1) Japanese Patent Laying-Open No. 2007-200505 (FIG. 4)

  However, the following problems remain in the head structure described above. In the structure of Patent Document 1, since light is introduced from outside the head by air propagation, the near-field light generating element is exposed on the head front end surface or between the near-field light generating element and the head front end surface. The head material needs to be transparent. Therefore, the near-field light generating element must be provided in a layer higher than the recording element with respect to the substrate. During operation, the head floats in an inclined posture with respect to the surface of the recording medium, so that a high position in the thickness direction of the substrate becomes the trailing end of the head (trailing edge). Will have. Near-field light assisted magnetic recording is a method in which a recording medium is heated by near-field light and then magnetized by a magnetic field. Therefore, it is desirable to arrange the near-field light generating element before the magnetic pole. Such an arrangement is difficult.

  On the other hand, in the structure of Patent Document 2, since a near-field light generating element, a main magnetic pole, and a sub-magnetic pole are arranged in this order from a low position in the thickness direction of the substrate, a magnetic field is applied after heating a minute region on the medium surface. Although there is an effect that the optical fiber can be connected, it is necessary to connect the optical fiber from the front end surface of the head, and the optical fiber arranged along the suspension must be bent until it is reversed at the front end of the head. The size of the head is 1 mm or less, and such bending is difficult mechanically, and it is also difficult to keep light confined in the core.

  As described above, it is difficult to route the optical fiber around the magnetic pole, and when the optical fiber is bent and routed, the optical loss in the optical fiber increases and it is not possible to generate near-field light having a desired intensity. .

  Accordingly, the present invention has been made in view of the above points, and can improve the degree of freedom in designing a path to generate near-field light and generate near-field light having a desired intensity. It is an object of the present invention to provide an assist magnetic recording head that can be used and an information recording / reproducing apparatus including the assist magnetic recording head.

The present invention provides the following means in order to solve the above problems.
The near-field light assisted magnetic recording head according to the present invention records information by causing magnetization reversal by heating a recording medium with near-field light and applying a recording magnetic field to the recording medium. The light energy generated by the light beam is converted into surface plasmon energy using the slider disposed opposite to the surface of the light guide, the light guide structure fixed to the slider and propagating the light beam, and the light beam reaching the tip of the light guide structure on the recording medium side. A near-field light generating element that converts and irradiates the recording medium with near-field light using the converted surface plasmon energy; and a main magnetic pole that is provided on the slider and applies the recording magnetic field to the recording medium. Is terminated at the front end portion of the light guide structure on the recording medium side, and the near-field light generating element is a near-field light generating element provided on the recording medium side. A near-field light generating base is provided on the opposite side of the tip of the element and the near-field light generating element, and includes a near-field light generating base connected to the tip of the light guide structure on the recording medium side. A near-field light assisted magnetic recording head is characterized in that the tip of the element is provided next to the main magnetic pole.

  The near-field light assisted magnetic recording head according to the present invention can bring the near-field light spot and the magnetic field spot close to each other in a very small area, and by changing the magnetization state of only the minute area on the surface of the recording medium, Enables high-density information recording. In addition, since the light beam that has reached the tip of the light guide structure on the recording medium side is temporarily converted into surface plasmon energy and the energy generated by the light beam is amplified, the route until the near-field light is generated becomes longer. Even so, desired near-field light can be generated.

  In the near-field light assisted magnetic recording head according to the present invention, the tip of the near-field light generating element, the main magnetic pole, and the light guide structure are sequentially provided along the rotation direction of the recording medium. . Note that a light-shielding film may be provided at the tip portion of the light guide structure on the recording medium side.

  According to the present invention, a desired area of a recording medium is heated by the near-field light generating element, and then the recording magnetic field by the main magnetic pole is irradiated, so that information can be recorded reliably.

  A near-field light-assisted magnetic recording head according to the present invention includes a sub-magnetic pole that is provided on a slider and absorbs a return magnetic field from a recording medium, and a coil that generates a recording magnetic field. The coil is provided in order along the rotation direction of the recording medium, the coil is provided between the sub magnetic pole and the main magnetic pole, and the tip of the near-field light generating element is provided between the coil and the main magnetic pole. It is characterized by that.

  The near-field light assisted magnetic recording head according to the present invention has a near-field light generating element positioned in front of the main pole in the scanning direction of the head, so that a magnetic field generated by the main pole is generated immediately after heating a minute area on the medium surface. Applied to enable high-density information recording.

  A near-field light-assisted magnetic recording head according to the present invention includes a sub-magnetic pole that is provided on a slider and absorbs a return magnetic field from a recording medium, and a coil that generates a recording magnetic field. It is provided in order along the rotation direction of the recording medium, the coil is provided between the sub magnetic pole and the main magnetic pole, and the tip of the near-field light generating element is provided between the coil and the sub magnetic pole. It is characterized by that.

  The near-field light assisted magnetic recording head according to the present invention has a near-field light generating element tip located immediately above the main magnetic pole, so that the near-field light assisted magnetic recording head is formed on the surface flattened at the nano level after the main pole is formed. A light generating element can be formed, and a near-field light generating element can be formed with high shape accuracy.

  The near-field light assisted magnetic recording head according to the present invention is characterized in that at least a part of the light guide structure has the same height as the coil on the substrate.

  The near-field light assisted magnetic recording head according to the present invention reduces the thickness of the entire head by providing the light guide structure and the coil layer in the same layer, and further reduces the thickness of the information recording / reproducing apparatus. Can be reduced.

  In the near-field light assisted magnetic recording head according to the present invention, the light guide structure is an optical waveguide having a substantially rectangular parallelepiped core portion and a clad portion surrounding the core portion and having a lower refractive index than the core portion. The field light generating base is arranged in the core part or in the vicinity of the surface.

  The near-field light assisted magnetic recording head according to the present invention generates highly efficient near-field light because the light propagation from the light source to the near-field light generating element has a very high energy efficiency due to the confinement structure due to the refractive index difference. Is realized.

  Further, the near-field light assisted magnetic recording head according to the present invention is characterized in that the core portion has a tapered structure in which the cross-sectional area of the core portion decreases as the light beam faces the recording medium.

  Since the near-field light assisted magnetic recording head according to the present invention reduces the light spot in the process of light propagation from the light source to the near-field light generating element, plasmons on the surface of the near-field light generating element are excited with high efficiency from the propagating light. As a result, high-efficiency near-field light generation is realized.

  In addition, the core part may be covered with the light shielding film ahead of the near-field light generating element base part in the propagation direction of the light flux.

  In the near-field light assisted magnetic recording head according to the present invention, the near-field light generating element is magnetically insulated from both the main magnetic pole and the sub-magnetic pole. A part of the magnetic pole connecting part for magnetically connecting the sub magnetic pole and the height from the substrate are the same. Specifically, the front end portion of the near-field light generating element is provided on the same plane as the end portions of the main magnetic pole and the sub magnetic pole on the recording medium side.

  In the near-field light assisted magnetic recording head according to the present invention, the near-field light generating element and the main magnetic pole can be brought close to each other, and recording can be performed in a very small area on the surface of the recording medium.

  In the near-field light assisted magnetic recording head according to the present invention, the near-field light generating element has a shape in which a cross-sectional area decreases toward the recording medium.

  The near-field light assisted magnetic recording head according to the present invention generates near-field light in a minute area defined by the size of the sharpened portion of the tip of the near-field light generating element. Only high-temperature information recording can be performed.

  Further, in the near-field light assisted magnetic recording head according to the present invention, the near-field light generating element base has a planar shape as viewed from the front end surface side of the near-field light assisted magnetic recording head from the front-end of the near-field light generating element. Is characterized in that it is wide in the direction perpendicular to the propagation direction of the luminous flux.

  The near-field light-assisted magnetic recording head according to the present invention has a large area of the near-field light generating element base that interacts with the light propagating through the light guide, and therefore can generate stronger surface plasmons. Driving with lower power consumption is possible.

  Further, the near-field light assisted magnetic recording head according to the present invention has a smooth curved surface in which the surface of the near-field light generating element from the base of the near-field light generating element to the tip of the near-field light generating element has a curvature radius of 50 nm or more. It is characterized by being.

  The near-field light assisted magnetic recording head according to the present invention can reduce the scattering of surface plasmons on the way, and can generate near-field light with higher efficiency.

Further, the near-field light assisted magnetic recording head according to the present invention is characterized in that the planar view shape of the near-field light generating element base portion viewed from the head front end side is substantially the same as the planar view shape of the core portion. The near-field light assisted magnetic recording head according to the present invention has a wide near-field light generating element base that interacts with light from the light guide, and therefore can generate near-field light with high efficiency. It also has the advantage that it can be easily manufactured.

  An information recording / reproducing apparatus according to the present invention includes a near-field light assisted magnetic recording head, a recording medium, a suspension arm including the near-field light assisted magnetic recording head, and a recording medium in a predetermined direction at a predetermined speed. Rotating drive unit for rotating, pivot for configuring the suspension arm to move in a direction parallel to the surface of the recording medium, an actuator for moving the suspension arm to a predetermined position on the surface of the recording medium, and a near-field light assisted magnetic recording head And a control unit for controlling the operation of the actuator.

  The information recording / reproducing apparatus according to the present invention realizes high-density information recording by strongly heating only a very small area on the surface of the recording medium with near-field light and simultaneously magnetizing it by applying a magnetic field.

  In the near-field light assisted magnetic recording head according to the present invention, it is possible to improve the degree of freedom in designing a path to generate near-field light and to generate near-field light having a desired intensity.

1 is a perspective view of an information recording / reproducing apparatus according to Embodiment 1. FIG. FIG. 3 is a cross-sectional view of the near-field light assisted magnetic recording head 2, the tip of a suspension 3, and a disk D according to the first embodiment. FIG. 3 is a view of a portion from the tip of the spot size converter 22 according to the first embodiment to the tip of a main magnetic pole 21 as viewed from the tip surface side of the head. (A) It is sectional drawing along A-A 'shown in FIG. (B) It is sectional drawing along B-B 'shown in FIG. (C) It is sectional drawing along C-C 'shown in FIG. (D) It is sectional drawing along D-D 'shown in FIG. FIG. 6 is a cross-sectional view of a near-field light assisted magnetic recording head 41, a tip of a suspension 3, and a disk D according to a second embodiment. FIG. 6 is an enlarged cross-sectional view of a front end portion of a near-field light assisted magnetic recording head 2 according to a third embodiment. (A) It is an expanded sectional view of the front-end | tip part of the near-field light assisted magnetic recording head 2 concerning Embodiment 4. FIG. (B) It is the figure which looked at the part from the front-end | tip of the spot size converter 22 to the front-end | tip of the main magnetic pole 21 from the front end surface side of the head. FIG. 9 is an enlarged cross-sectional view of a tip portion of a near-field light assisted magnetic recording head 2 according to a fifth embodiment. FIG. 10 is an enlarged cross-sectional view of a front end portion of a near-field light assisted magnetic recording head 2 according to a sixth embodiment. FIG. 10 is an enlarged cross-sectional view of a tip portion of a near-field light assisted magnetic recording head 2 according to a seventh embodiment. FIG. 10 is a view of a portion from the tip of a spot size converter 22 according to an eighth embodiment to the tip of a main magnetic pole 21 as seen from the tip surface side of the head. It is the figure which looked at the part from the front-end | tip of the spot size converter 22 which concerns on Embodiment 9 to the front-end | tip of the main pole 21 from the front end surface side of the head. It is the figure which looked at the part from the front-end | tip of the spot size converter 22 which concerns on Embodiment 10 to the front-end | tip of the main pole 21 from the front end surface side of the head. FIG. 10 is a view of a portion from a tip end of a spot size converter 22 according to an eleventh embodiment to a tip end of a main magnetic pole 21 as viewed from the tip end side of the head.

(First embodiment)
A first embodiment of a near-field light assisted magnetic recording head and an information recording / reproducing apparatus according to the present invention will be described below with reference to FIGS. Note that the information recording / reproducing apparatus 1 of the present embodiment is an apparatus for writing on a disk (magnetic recording medium) D having a perpendicular recording layer D1 by a perpendicular recording method. Further, in the present embodiment, an air floating type in which the near-field light assisted magnetic recording head 2 is floated using the flow of air rotating the disk D will be described as an example.

  As shown in FIG. 1, the information recording / reproducing apparatus 1 of the present embodiment includes a near-field light assisted magnetic recording head 2 having a spot size converter (light guide structure) 22 to be described later, and the surface of a disk D (magnetic recording medium). Near-field light assisted magnetism that is movable in two directions (X-axis and Y-axis) parallel to the surface of the disk D and orthogonal to each other. A suspension 3 that supports the recording head 2 on the front end side, a laser light source (light source) 5 that causes a light beam to enter the optical fiber 4 from the base end side of the optical fiber (light flux introducing means) 4, and a base end of the suspension 3 And an actuator 6 that scans and moves the suspension 3 in the XY directions parallel to the disk D, and a spindle motor (rotary drive) that rotates the disk D in a certain direction. Part) 7, a control part 8 for controlling the operation of the laser light source 5 and supplying a current modulated in accordance with information to a coil 36, which will be described later, and a housing 9 for housing these components therein. I have.

  The housing 9 is made of a metal material such as aluminum and has a quadrangular shape when viewed from the top, and a recess 9a for accommodating each component is formed inside. Further, a lid (not shown) is detachably fixed to the housing 9 so as to close the opening of the recess 9a. A spindle motor 7 is attached to the approximate center of the recess 9a, and the disc D is detachably fixed by fitting a center hole into the spindle motor 7. The actuator 6 is attached to the corner of the recess 9a. A carriage 11 is attached to the actuator 6 via a bearing 10, and a suspension 3 is attached to the tip of the carriage 11.

  The carriage 11 and the suspension 3 are retracted from the disk D by driving the actuator 6 when the disk D stops rotating. The near-field light assisted magnetic recording head 2 and the suspension 3 constitute a head gimbal assembly 12. The laser light source 5 is mounted in the recess 9 a so as to be adjacent to the actuator 6. A control unit 8 is attached adjacent to the laser light source 5. The laser light source 5 may be mounted on the suspension 3.

  FIG. 2 shows a cross-section of the near-field light-assisted magnetic recording head 2 and the tip of the suspension 3 and the disk D according to this embodiment. The near-field light assisted magnetic recording head 2 heats the rotating disk D with near-field light and applies a recording magnetic field in a direction perpendicular to the disk D to cause magnetization reversal in the recording layer D1 to store information. It is to be recorded. As shown in FIG. 2, the near-field light assisted magnetic recording head 2 is disposed so as to face the disk D in a state where it floats a predetermined distance from the surface of the disk D, and has a slider 20 having a facing surface 20a facing the disk D. A main magnetic pole 21 fixed to the front end surface of the slider 20 and a spot size converter (light guide structure) 22 fixed adjacent to the main magnetic pole 21 are provided. A magnetic field is generated from the tip of the main pole 21 facing the disk D. Further, the near-field optical head 2 of the present embodiment includes a reproducing element (not shown) fixed adjacent to the spot size converter (light guide structure) 22. Note that the rotation direction of the disk D is a direction from right to left in FIG.

  The suspension 3 includes a base plate (not shown), a hinge (not shown), a load beam 24, and a flexure 25, and has a function of floating the near-field light assisted magnetic recording head 2 in the state of being close to the disk D. The load beam 24 applies a load that pushes the near-field light-assisted magnetic recording head 2 toward the disk D direction. A light guide unit 26 is provided on the surface of the flexure 25 on the disk D side (downward in the drawing). The front end of the light guide unit 26 is a cut surface 27 cut obliquely. The light guide unit 26 has a function of guiding light, such as an optical fiber or a resin waveguide.

  The spot size converter 22 is a tapered waveguide with a triangular cross section, and the light incident surface 28 is a triangle that is substantially similar to the tip 29, but is larger in size than the tip 29. The tip 29 is in contact with a near-field light generating element base 32. The tip of the tip portion 29 (lower in the figure) is covered with a light shielding film 33. The other end of the near-field light generating element 31 is a near-field light generating element tip 34 that generates near-field light. The near-field light generating element 31 is made of a material such as Au or Ag that excites surface plasmons when irradiated with incident light. The near-field light generating element 31 converts light energy generated by the light beam into surface plasmon energy using the light beam that has reached the tip of the spot size converter 22 on the disk D side, and also uses the converted surface plasmon energy to generate a near-field field. The disk D is irradiated with light.

  The slider 20 is manufactured by stacking elements on a substrate made of AlTiC. In FIG. 2, the right side in the figure is the AlTiC substrate side, and each element is stacked in the left direction in the figure. In this embodiment, the sub magnetic pole 35, the layer including the coil 36, the near-field light generating element tip 34, and the main magnetic pole 21 are laminated in this order from the substrate side (right side in the figure). Although the base 32 of the near-field light generating element 31 is located above the main magnetic pole 21 (left side in the figure), the near-field light generating element tip 34 has the main magnetic pole by having a curved portion. It is located below 21 (right in the figure). The main magnetic pole 21 and the sub magnetic pole 35 are magnetically connected by a magnetic pole connection portion 37 and together with the coil 36 form an electromagnet.

  FIG. 3 is a view of a portion from the tip of the spot size converter (light guide structure) 22 to the tip of the main magnetic pole 21 as seen from the tip surface side of the near-field light assisted magnetic recording head 2. FIG. 4 shows a cross section along A-A ′, B-B ′, C-C ′, and D-D ′ shown in FIG. 3. For simplicity, the insulating layer and the light shielding film 33 between the element layers are not shown. The spot size converter (light guide structure) 22 has a structure in which a core having a predetermined refractive index is surrounded by a clad (not shown) having a lower refractive index, and the width and height of the core gradually increase. It has a tapered structure that becomes smaller. There is no cladding layer near the tip, and the near-field light generating element base 32 is in contact with the core. The main magnetic pole 21 is located below the near-field light generating element base 32. The near-field light generating element 31 passes through the same height as the main magnetic pole 21 while being shifted laterally (leftward in FIGS. 3 and 4) from the main magnetic pole 21 in a plane parallel to the substrate. It reaches back to the tip 34 of the near-field light generating element.

  In the near-field light assisted magnetic recording head 2 having such a structure, the near-field light generating element distal end portion 34 is located between the main magnetic pole 21 and the sub magnetic pole 35. The spot size converter (light guide structure) 22 has a tapered triangular frustum shape, one of the three side surfaces of the core is parallel to the substrate, and the remaining two surfaces form a predetermined angle with respect to the substrate. Yes. The propagation direction of the light propagating through the inside is substantially parallel to the substrate but slightly tilted, and gradually approaches toward the plane parallel to the substrate. Thus, since the spot size converter (light guide structure) 22 has a three-dimensional structure, the main magnetic pole 21 in the very vicinity thereof is formed below (substrate side) the spot size converter (light guide structure) 22. However, it can be formed with higher positional accuracy than it is formed above. When the near-field light assisted magnetic recording head 2 is operated, the lower side with respect to the thickness of the substrate is the leading edge, and the upper side is the trailing edge, and the spot size converter (light guide structure) 22 is below the substrate. It is closer to the trailing edge than the main pole 21 on the direction side. The near-field light generating element 31 is located on the trailing edge side with respect to the main magnetic pole 21 at the base 32, while the front-end portion 34 of the near-field light generating element is located on the leading edge side with respect to the main magnetic pole 21. Thus, by making the shape of the near-field light generating element 31 curved in the middle as in the present embodiment, the main magnetic pole 21 is generated after the medium surface is temporarily heated by the near-field light. Can be recorded by a magnetic field. The light guide 26 is disposed along the suspension 3, and only changes the light propagation direction at the cutting surface 27 at the tip, and has a structure that is mechanically and optically reasonable. Further, the light propagating through the spot size converter (light guide structure) 22 is applied to the surface plasmon of the near-field light generating element 31 by irradiating the base 32 of the near-field light generating element 31 with the light. However, since other light components are absorbed or reflected by the light shielding film 33, they do not reach the disk D. Since the disk D is irradiated only with the near-field light generated from the tip 34 of the near-field light generating element, only a very small area can be heated. Thereby, only the area where the main magnetic pole 21 performs magnetic recording is locally heated, thereby realizing high-density recording.

  That is, according to the present invention, since the recording magnetic field by the main magnetic pole 21 is irradiated after the desired area of the disk D is heated with near-field light, information can be recorded reliably. Further, since the light beam that has reached the tip of the spot size converter 22 on the recording medium side is once converted into surface plasmon energy and the energy by the light beam is amplified, the route until the near-field light is generated is routed. Even if the length becomes longer, the desired near-field light can be generated.

(Second embodiment)
FIG. 5 shows a cross-section of the near-field light-assisted magnetic recording head 41, the tip of the suspension 3, and the disk D according to the second embodiment. The same parts as those of the first embodiment are given the same reference numerals and the description thereof is omitted. The feature of the near-field light assisted magnetic recording head 41 is that the main magnetic pole 42, the coil 36, and the sub magnetic pole 43 are formed in this order on the substrate. That is, the positions of the main magnetic pole 42 and the sub magnetic pole 43 are different from those of the first embodiment. It is a point that is reversed. The near-field light generating element 45 has a base portion 32 in contact with the spot size converter (light guide structure) 22, and a near-field light generating element distal end portion 44 located between the main magnetic pole 42 and the coil 36. . Since the sub magnetic pole 43 is larger in size than the main magnetic pole 42 and required manufacturing accuracy is low, it is not necessary to flatten the surface with high accuracy after the coil 36 is manufactured, and the manufacturing is easier. .

(Third embodiment)
FIG. 6 is an enlarged cross-sectional view of the front end portion of the near-field light assisted magnetic recording head according to the third embodiment. The same parts as those of the first embodiment are given the same reference numerals and the description thereof is omitted. In this embodiment, the spot size converter (light guide structure) 22 includes a core 51, a lower clad 52, and an upper clad 53. The core 51 is made of a material having a higher refractive index than the lower clad 52 and the upper clad 53. The lower clad 52 and the upper clad 53 are made of the same material, but can be made of different materials as long as the refractive index is lower than that of the core 51. The core 51 protrudes to the tip side (lower side in the drawing) from the lower clad 52, and the near-field light generating element base 32 is located in contact with the core 51 in a portion where the lower clad 52 is not present. The tip of the core 51 is covered with a light shielding film 33. The upper clad 53 covers both the core 51 and the light shielding film 33. Light propagates in a form confined inside the core 51 due to the refractive index difference between the core 51, the lower clad 52, and the upper clad 53, but at the same time as the lower clad 52 disappears at the tip shown in the figure, the core 51 Since the cross-sectional size of the light becomes too small, it becomes impossible to confine light. Further, the light cannot be advanced further by the light shielding film 33 at the tip of the core 51. The near-field light generating element base 32 is positioned so as to be exposed at the tip of the core 51, and by generating surface plasmons by light irradiation, the light energy is absorbed, and the near-field light generating element tip Propagate toward the unit 34. By adopting such a configuration, light achieves high propagation efficiency by confinement due to the difference in refractive index up to the head tip, and energy propagates through a very small space by giving energy to the plasmon at the head tip, Finally, highly efficient near-field light can be generated.

(Fourth embodiment)
FIG. 7A is an enlarged cross-sectional view of the front end portion of the near-field light assisted magnetic recording head 2 according to the fourth embodiment, and FIG. 7B is a diagram illustrating the main magnetic pole 21 from the front end of the spot size converter (light guide structure) 22. FIG. 6 is a view of the portion up to the tip of the near-field light assisted magnetic recording head 2 as seen from the tip surface side. The same parts as those of the first embodiment are given the same reference numerals and the description thereof is omitted. In the present embodiment, the near-field light generating element tip 61 has a tapered structure in both the thickness direction and the width direction. The energy propagating from the near-field light generating element base 32 in the form of surface plasmon is scattered by the near-field light generating element tip 61 and becomes near-field light. The spot size of the near-field light generating element is the near-field light generating element. This greatly depends on the size of the tip 61. In this embodiment, the tip portion 61 of the near-field light generating element has a tapered structure, so that energy can be further localized in addition to the effects of the other embodiments, and a higher-density near-field light-assisted magnetic recording can be performed. Realize.

(Fifth embodiment)
FIG. 8 is an enlarged cross-sectional view of the tip of the near-field light assisted magnetic recording head 2 according to the fifth embodiment. The same parts as those of the first embodiment are given the same reference numerals and the description thereof is omitted. The present embodiment is different from the first embodiment in that the laser 71 is fixed on the upper surface of the near-field light assisted magnetic recording head 2. Further, the light incident surface 72 of the spot size converter (light guide structure) 73 reflects the light emitted from the laser 71 so as to be coupled to the inside of the spot size converter (light guide structure) 73. Mounting the laser 71 directly on the near-field light-assisted magnetic recording head 2 makes it easier to assemble the head gimbal assembly, and the flying posture of the near-field light-assisted magnetic recording head 2 from the disk D surface is more stable. The effect of doing.

(Sixth embodiment)
FIG. 9 is an enlarged cross-sectional view of the front end portion of the near-field light assisted magnetic recording head 2 according to the sixth embodiment. The same parts as those of the first embodiment are given the same reference numerals and the description thereof is omitted. In the present embodiment, the straight waveguide 81 has a function of guiding light within the head. The straight waveguide 81 has a rectangular cross section, and the incident port 82 has the same shape as the tip portion 29. Such a structure can be manufactured only by planar patterning and can be manufactured with higher shape accuracy, so that highly efficient light propagation is possible.

(Seventh embodiment)
FIG. 10 is an enlarged cross-sectional view of the tip of the near-field light assisted magnetic recording head 2 according to the seventh embodiment. The same parts as those of the first embodiment are given the same reference numerals and the description thereof is omitted. In this embodiment, the straight waveguide 91 is at the same height from the coil 36 and the substrate. Specifically, the coil 36 is formed in a direction orthogonal to the disk D. The straight waveguide 91 is provided side by side on the opposite side to the disk D side of the coil 36, and is provided along the direction in which the coil 36 is formed. Such a structure can also be realized by bending the near-field light generating element 31 in a plane parallel to the substrate. Thereby, the thickness of the entire head can be reduced, and the flying height can be reduced and the apparatus can be downsized.

(Eighth embodiment)
FIG. 11 shows a portion from the tip of the spot size converter (light guide structure) 22 to the tip of the main pole 21 in the near-field light-assisted magnetic recording head 2 according to the eighth embodiment. It is the figure seen from the front end surface side. The same parts as those in FIG. 3 (Embodiment 1) are denoted by the same reference numerals and the description thereof is omitted. In the present embodiment, the near-field light generating element 101 is bent in the thickness direction of the substrate while being displaced in the lateral direction of the main magnetic pole 21, and the near-field light generating element tip 34 is located below the main magnetic pole 21. Is the same as that of the first embodiment, but the near-field light generating element base 102 has a substantially disc shape. The light that has propagated through the spot size converter 22 interacts with the near-field light generating element base 102 to generate surface plasmons. At this time, the surface area of the near-field light generating element base 102 is larger, A large interaction occurs and the plasmon generation efficiency increases. As a result, the intensity of the near-field light generated from the tip portion 34 of the near-field light generating element is increased, and the medium can be heated with lower power consumption.

(Ninth embodiment)
FIG. 12 shows a portion from the tip of the spot size converter (light guide structure) 22 to the tip of the main pole 21 in the near-field light-assisted magnetic recording head 2 according to the ninth embodiment. It is the figure seen from the front end surface side. The same parts as those in FIG. 11 (Embodiment 8) are denoted by the same reference numerals and the description thereof is omitted. In the present embodiment, the near-field light generating element 111 has a shape in which the width is gradually reduced from the near-field light generating element base portion 112 toward the near-field light generating element tip portion 113. Since the generated near-field light is localized in a space defined by the width of the near-field light generating element front end portion 113, the near-field light generating element front end portion 113 is narrowed so that the near-field light is generated in a smaller area. Light can be localized. Further, the near-field light generating element 111 has a smooth surface throughout and does not have a sharp portion (such as a protrusion). Typically, the etching mask is designed so that the radius of curvature of the surface is 50 nm or more. The surface plasmon is greatly affected by the minute shape of the surface, and the surface plasmon is scattered particularly when there is a sharp point. By forming, a near-field light can be generated with higher efficiency, and a recording apparatus with low power consumption and less erroneous recording is realized.

(Tenth embodiment)
FIG. 13 shows a portion from the tip of the spot size converter (light guide structure) 22 to the tip of the main pole 21 in the near-field light-assisted magnetic recording head 2 according to the tenth embodiment. It is the figure seen from the front end surface side. The same parts as those in FIG. 12 (Embodiment 9) are given the same reference numerals and the description thereof is omitted. In the near-field light generating element 121 of the present embodiment, the near-field light generating element base 122 has a horizontally longer shape than the spot size converter 22. The light propagating through the spot size converter 22 interacts with the near-field light generating element base 122 to generate surface plasmons on the surface of the near-field light generating element base 122. As in the present embodiment, If the near-field light generating element base 122 is longer than the spot size converter 22, most components of the light propagated through the spot size converter 22 may interact with the near-field light generating element base 122. It is possible to generate near-field light with higher efficiency.

(Eleventh embodiment)
FIG. 14 shows a portion from the tip of the spot size converter (light guide structure) 22 to the tip of the main pole 21 in the near-field light-assisted magnetic recording head 2 according to the eleventh embodiment. It is the figure seen from the front end surface side. The same parts as those in FIG. 13 (Embodiment 8) are denoted by the same reference numerals and the description thereof is omitted. In the present embodiment, the shape of the near-field light generating element base 132 in the near-field light generating element 131 is substantially the same as that of the spot size converter 22. With such a structure, most components of the light propagated through the spot size converter 22 can interact with the near-field light generating element base 132, and near-field light can be generated with high efficiency. Further, when the spot size converter 22 is manufactured by etching, there is an advantage that the near-field light generating element base 132 can be easily manufactured in the same process.

(Other embodiments)
The present invention is not limited to the configuration of each embodiment. Specifically, the light beam only needs to terminate at the tip portion of the spot size converter 22 on the disk D side, and the present invention is not limited to the configuration including the light shielding film 33.

  INDUSTRIAL APPLICABILITY The present invention is used as an information recording / reproducing apparatus built in a computer or household electric product, particularly as one of hard disk components that require large capacity recording.

DESCRIPTION OF SYMBOLS 1 Information recording / reproducing apparatus 2 Near-field light-assisted magnetic recording head 3 Suspension 4 Optical fiber 5 Laser light source 6 Actuator 7 Spindle motor 8 Control part 9 Housing 9a Recess 10 Bearing 11 Carriage 12 Head gimbal assembly 20 Slider 20a Opposing surface 21 Main pole 22 Spot size converter (light guide structure)
24 load beam 25 flexure 26 light guide 27 cut surface 28 light incident surface 29 tip 31 near-field light generating element 32 near-field light generating element base 33 light-shielding film 34 near-field light generating element tip 35 sub magnetic pole 36 coil 37 magnetic pole Connection part 41 Near-field light assisted magnetic recording head 42 Main magnetic pole 43 Sub-magnetic pole 44 Near-field light generating element tip 45 Near-field light generating element 51 Core 52 Lower clad 53 Upper clad 61 Near-field light generating element tip 71 Laser 72 Light Incident surface 73 Spot size converter (light guide structure)
81 linear waveguide 82 entrance 91 linear waveguide 101, 111, 121, 131 near-field light generating element 102, 112, 122, 132 near-field light generating element base D disk D1 perpendicular recording layer

Claims (15)

A near-field light-assisted magnetic recording head that records information by heating a recording medium with near-field light and applying a recording magnetic field to the recording medium to cause magnetization reversal,
A slider disposed opposite to the surface of the recording medium;
A light guide structure fixed to the slider and propagating a light beam;
Using the light beam that has reached the tip of the light guide structure on the recording medium side, light energy from the light beam is converted into surface plasmon energy, and the near-field light is recorded using the converted surface plasmon energy. A near-field light generating element for irradiating the medium;
A main magnetic pole provided on the slider and applying the recording magnetic field to the recording medium;
The light flux terminates at a tip portion on the recording medium side of the light guide structure,
The near-field light generating element is provided on the side opposite to the near-field light generating element tip provided on the recording medium side and the near-field light generating element tip, and A near-field light generating element base connected to the tip portion on the recording medium side,
The near-field light assisted magnetic recording head, wherein the tip of the near-field light generating element is provided next to the main magnetic pole.   2. The near-field light assisted magnetism according to claim 1, wherein the near-field light generating element front end portion, the main magnetic pole, and the light guide structure are sequentially provided along a rotation direction of the recording medium. Recording head.   The near-field light-assisted magnetic recording head according to claim 1, further comprising a light-shielding film at a tip portion of the light guide structure on the recording medium side. A sub-magnetic pole provided on the slider and absorbing a return magnetic field from the recording medium, and a coil for generating the recording magnetic field,
The sub magnetic pole and the main magnetic pole are sequentially provided along the rotation direction of the recording medium,
The coil is provided between the sub magnetic pole and the main magnetic pole,
The near-field light assisted magnetic recording head according to claim 1, wherein a tip portion of the near-field light generating element is provided between the coil and the main magnetic pole. A sub magnetic pole provided on the slider and absorbing a return magnetic field from the recording medium;
A coil for generating the recording magnetic field,
The sub magnetic pole and the main magnetic pole are sequentially provided along the rotation direction of the recording medium,
The coil is provided between the sub magnetic pole and the main magnetic pole,
The near-field light assisted magnetic recording head according to claim 1, wherein the tip of the near-field light generating element is provided between the coil and the sub magnetic pole. The coil is formed in a direction orthogonal to the recording medium,
2. The light guide structure according to claim 1, wherein at least a part of the light guide structure is provided side by side on the opposite side to the recording medium side of the coil, and is provided along a direction in which the coil is formed. The near-field light-assisted magnetic recording head described. The near-field light-assisted magnetic recording head according to claim 1,
The light guide structure is an optical waveguide composed of a substantially rectangular parallelepiped core part and a clad part surrounding the core part and having a lower refractive index than the core part,
The near-field light assisted magnetic recording head, wherein the near-field light generating element base is disposed inside or near the surface of the core.   The near-field light assisted magnetic recording head according to claim 7, wherein the core portion has a tapered structure in which a cross-sectional area of the core portion decreases as the light beam faces the recording medium.   The near-field light assisted magnetic recording head according to claim 7, wherein the core portion is covered with a light shielding film in front of the near-field light generating element base in the propagation direction of the light beam.   2. The near-field light assisted magnetism according to claim 1, wherein a tip portion of the near-field light generating element is provided on the same plane as ends of the main magnetic pole and the sub-magnetic pole on the recording medium side. Recording head.   The near-field light assisted magnetic recording head according to claim 1, wherein the near-field light generating element has a shape whose cross-sectional area decreases toward the recording medium.   The near-field light generating element base has a planar view shape as viewed from the front end side of the near-field light assisted magnetic recording head, and has a width in a direction perpendicular to the propagation direction of the light flux than the front end of the near-field light generating element. The near-field light-assisted magnetic recording head according to claim 1, wherein the near-field light-assisted magnetic recording head is wide.   The surface of the near-field light generating element extending from the near-field light generating element base to the tip of the near-field light generating element is a smooth curved surface having a curvature radius of 50 nm or more. Near-field light-assisted magnetic recording head.   The near-field light generating element base has a plan-view shape viewed from the front end surface side of the near-field light-assisted magnetic recording head is substantially the same as a plan-view shape of the tip portion of the core portion on the recording medium side. The near-field light-assisted magnetic recording head according to claim 7. A near-field light-assisted magnetic recording head according to claim 1;
The recording medium;
A suspension arm comprising the near-field light-assisted magnetic recording head;
A rotation drive unit for rotating the recording medium in a predetermined direction at a predetermined speed;
A pivot configured to allow the suspension arm to move in a direction parallel to the recording medium surface;
An actuator for moving the suspension arm to a predetermined position on the surface of the recording medium;
An information recording / reproducing apparatus comprising: a recording / reproducing drive for the near-field light assisted magnetic recording head; and a control unit for controlling operations of the rotation driving unit and the actuator.

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