JP2010061704A - Magnetic head and magnetic disk device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic head or the like in which a main magnetic pole and a light irradiation position are set close to each other while preventing illumination light being propagated from being absorbed by the main magnetic pole. <P>SOLUTION: The magnetic head 100 includes: an optical waveguide 131 having a core layer 131 and a clad layer 132, extending toward an air-bearing surface F to expose a part of the core layer in the thickness direction T near one surface E of the core layer, and configured to propagate and emit illumination light; and a main magnetic pole 121 formed on one surface E side of the core layer, separated from the core layer, extending toward the air-bearing surface in parallel with the core layer, extending toward the air-bearing surface close to the core layer in a part near the air-bearing surface, and having a part near the air-bearing surface brought into contact with or close to the core layer to be exposed on the air-bearing surface. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a magnetic head and a magnetic disk device.

  In a magnetic disk device typified by a hard disk device (HDD), in order to improve the recording density, the fine structure of the crystal grains of the magnetic layer in the storage medium has progressed to the extent that thermal fluctuation becomes a problem. In order to reduce this thermal fluctuation, it is suitable to add an element having a high coercive force to the magnetic layer. However, the higher the coercive force, the more difficult it is to write with a magnetic field from a magnetic head. Therefore, a heat-assisted recording method is proposed in which a minute heat spot is formed on the storage medium and heated rapidly, the coercive force is temporarily lowered by heat, recording is performed with a magnetic field, and the coercive force is recovered by rapid cooling. Has been. This heat spot is generated by irradiating the storage medium with a light spot from the magnetic head and absorbing it with the storage medium. For high-density recording, since the range covered by the magnetic field and the range of the heat spot are limited, it is required to form the heat spot in the vicinity of the magnetic pole. On the other hand, a head having a structure incorporating a waveguide through which light propagates has been proposed.

  For example, in an optical head, a structure is known in which an optical waveguide including a core through which light propagates and a clad sandwiching the core is laminated on a substrate (see, for example, Patent Document 1). In this optical head, a first multilayer film having an opening for generating a light spot is formed at the tip of an optical waveguide provided on a substrate, and light propagating through the core is formed on the first multilayer film. A second multilayer film and a reflection mirror that deflect to the multilayer film side are provided. In this structure, the light propagating in the core is largely deflected to the first multilayer film side on the substrate by the second multilayer film and irradiated from the opening.

  In addition, the core is directly disposed on the magnetic head, the first multilayer film having an opening for irradiating light at the tip of the core, and the light propagating through the core is deflected to the first multilayer film. A structure in which a second multilayer film is arranged is known (see, for example, Patent Document 2). The tip surface of the core is in contact with both the first multilayer film and the second multilayer film.

Also, a structure is known in which a special metal layer is provided on the core side of the magnetic pole to guide light using the plasmon effect generated on the metal surface and generate a light spot smaller than the size of the core. (For example, refer to Patent Document 3).
JP 2006-331508 A JP 2006-73105 A JP 2007-164936 A

  However, the optical head that largely deflects the light conducted through the optical waveguide composed of the core and the clad toward the first multilayer film on the substrate is from the height of the core to the height near the substrate, that is, the thickness of the core. It is necessary to deflect the light over a height obtained by adding the thickness of the clad to half of the thickness. For this reason, it is difficult to manufacture, and it is not easy to bring the light spot close to the magnetic pole.

  Further, the structure in which the core is directly disposed on the magnetic head has a problem that light is absorbed by the metal portion of the magnetic head. For example, a magnetic material used for the main pole of a magnetic head generally has a high refractive index optically exceeding n = 2. Furthermore, the refractive index in the visible light region generally increases as the wavelength increases. When a relatively short wavelength blue-violet laser is used, the refractive index of the main pole material is comparable or lower than the refractive index of the material used in the optical waveguide. However, when a red laser that can output with a light-emitting element that is easy to manufacture is used, the refractive index of the main magnetic pole material exceeds the refractive index of the optical waveguide material, so that the light is deflected to the magnetic pole side and a part of the light is To be absorbed. When the contact distance between the core and the magnetic pole is long, the loss of light increases. Further, the light absorbed by the magnetic pole becomes heat and raises the temperature of the magnetic pole. Since the main magnetic pole is a microstructure member that matches the recording track, heat conduction is hindered and the temperature tends to rise. The generation efficiency of the magnetic force decreases due to the temperature rise of the magnetic pole.

  In the configuration using the plasmon effect, light is guided not by a transparent material but by a metal, so light absorption by the metal is inevitable. Further, both the metal and the magnetic pole are heated by the absorbed light, and the generation efficiency of the magnetic force is lowered.

  In view of the above circumstances, the problem of the magnetic head and the magnetic disk device disclosed in the present disclosure is to bring the main magnetic pole and the irradiation position of the light close to each other while suppressing propagation light being propagated to the main magnetic pole.

The basic form of the magnetic head according to the present disclosure has a layer structure, and the air bearing surface composed of one end surface of the layer structure is levitated toward a relatively moving storage medium, and information is magnetically recorded on the storage medium. A magnetic head,
A part of the core layer in the thickness direction, which is close to one of both surfaces of the core layer, is exposed to the air bearing surface and is irradiated onto the storage medium. An optical waveguide that propagates the irradiation light and emits it from the air bearing surface;
A main magnetic pole having a layer shape for guiding magnetic force for recording information on the storage medium and acting on the storage medium. The main pole is formed on the one surface side of the core layer and is separated from the core layer. It extends toward the air bearing surface parallel to the layer, and extends obliquely toward the air bearing surface while approaching the core layer at a portion near the air bearing surface, and the vicinity of the air bearing surface is in contact with or close to the core layer. A main magnetic pole exposed on the air bearing surface.

The basic form of the magnetic disk device disclosed herein is:
A storage medium on which information is magnetically recorded;
A magnetic head that has a layer structure, and floats an air bearing surface composed of one end face of the layer structure toward the relative moving storage medium, and magnetically records information on the storage medium;
The magnetic head is
A part of the core layer in the thickness direction, which is close to one of both surfaces of the core layer, is exposed to the air bearing surface and is irradiated onto the storage medium. An optical waveguide that propagates the irradiation light and emits it from the air bearing surface;
A main magnetic pole having a layer shape for guiding magnetic force for recording information on the storage medium and acting on the storage medium. The main pole is formed on the one surface side of the core layer and is separated from the core layer. It extends toward the air bearing surface parallel to the layer, and extends obliquely toward the air bearing surface while approaching the core layer at a portion near the air bearing surface, and the vicinity of the air bearing surface is in contact with or close to the core layer. A main magnetic pole exposed on the air bearing surface.

  According to these basic forms, the main pole extends toward the air bearing surface along the core layer, but does not contact or approach the core layer to the vicinity of the air bearing surface. For this reason, even if the main magnetic pole is made of a magnetic material having a higher refractive index than the core layer, the irradiation light of the core layer is not absorbed by the main magnetic pole up to the vicinity of the air bearing surface. Therefore, the main magnetic pole and the irradiation position of the light can be brought close to each other while suppressing the propagating irradiation light from being absorbed by the main magnetic pole.

  According to the above-described basic form of the magnetic head and the magnetic disk device of the present disclosure described above, the main magnetic pole and the light irradiation position can be disposed close to each other while suppressing the propagating irradiation light from being absorbed by the main magnetic pole. .

  Hereinafter, specific embodiments of the magnetic head and the magnetic disk device according to the present disclosure will be described.

  FIG. 1 is a diagram showing a specific embodiment of a magnetic disk device.

  A magnetic disk device 1 shown in FIG. 1 is provided with a rotary actuator 6 that generates a rotational driving force having a rotation axis in a direction perpendicular to the drawing. The rotary actuator 6 supports the suspension arm 5. The suspension arm 5 rotates in response to the rotational driving force of the rotary actuator 6. A magnetic head 100 is attached to the tip of the suspension arm 5 via a gimbal 4 as a support. Specifically, the magnetic head 100 is formed at the tip of a magnetic head slider attached to the gimbal 4 and floats on the magnetic disk 2 together with the magnetic head slider. The magnetic head 100 reads information from the magnetic disk 2 and writes information to the magnetic disk 2.

  When reading or writing information, the rotary arm 6 rotates the suspension arm 5 to move the magnetic head 100 to a target position on the magnetic disk 2, thereby reading information from the magnetic disk 2 or magnetically. Information is written to the disk 2. A large number of tracks 7 are concentrically provided on the surface of the disk-shaped magnetic disk 2, and each track 7 has a storage area for storing information. Information is represented by the direction of magnetization arranged in the storage area. The magnetic disk 2 rotates in the plane of the drawing with the center of the disk as the center of rotation, and the magnetic head 100 disposed near the surface of the magnetic disk 2 sequentially approaches the storage area of the rotating magnetic disk 2.

  At the time of recording information, an electric recording signal and light are input to the magnetic head 100 adjacent to the magnetic disk 2, and the magnetic head 100 applies a magnetic field and light according to the input recording signal, and the recording signal The information carried in the storage area is recorded in the form of the magnetization direction of those storage areas. In reproducing information, the magnetic head 100 takes out information recorded in the format of the magnetization direction in each storage area by generating an electric reproduction signal in accordance with the magnetic field generated from each magnetization. Here, the magnetic disk 2 corresponds to an example of the storage medium in the basic form described above.

[First Embodiment]
2, 3 and 4 are views showing a specific first embodiment of the magnetic head. 2 is a perspective view showing the structure of the main part inside the magnetic head obliquely, FIG. 3 is a sectional view, and FIG. 4 is a view seen from the magnetic disk side.

  The magnetic head 100 shown in FIGS. 2 to 4 has a layer structure, and the air bearing surface F (see FIG. 3) formed by one end surface of the layer structure is levitated toward the magnetic disk 2. The track of the magnetic disk 2 moves in the direction of the arrow shown as the track direction T. That is, the magnetic head 100 moves relative to the track in the direction opposite to the arrow in the track direction T. A direction crossing the track direction T is defined as a cross track direction C. The magnetic head 100 has a layer structure laminated in the track direction T. Hereinafter, the thickness direction of each layer is also referred to as a track direction T, and the width direction is also referred to as a cross track direction C.

  The magnetic head 100 includes a reproducing element 11, a recording element 12, and an optical waveguide 13. In FIG. 2, the reproducing element 11 is not shown.

  The reproduction element 11 detects a magnetic field and outputs a reproduction signal corresponding to the magnetic field. The reproducing element 11 is, for example, a GMR (giant magnetoresistive) element. The reproducing element 11 is sandwiched between a pair of magnetic shields 14 and further separated from the recording element 12 by another magnetic shield 15.

The optical waveguide 13 has a core layer 131 and a cladding layer 132 sandwiching the core layer 131. The optical waveguide 13 extends toward the air bearing surface F, and propagates laser light emitted from a light emitting device (not shown) to the air bearing surface F. In FIG. 2, the cladding layer 132 is not shown for easy understanding of the structure, and in FIG. 3, the cladding layer 132 is hatched. In the magnetic head 100, for example, red laser light having a wavelength of 660 nm is used. The core layer 131 and the clad layer 132 do not have a significant value for the extinction coefficient (k) of the complex refractive index expressed by n ^* = n−jk with respect to the wavelength of the laser beam used (k≈0). ), That is, it is made of a transparent and non-magnetic material. As a material of the core layer 131, for example, a material having a higher refractive index than the material of the cladding layer 132 represented by Ta2O5 (n = 2.11) or TiO2 (n = 2.29) can be used. Further, as the material of the cladding layer 132, for example, a material having a lower refractive index than the material of the core layer 131 typified by SiO2 (n = 1.46) or Al2O3 (n = 1.77) can be employed. .

  Further, the optical waveguide 13 is provided with an optical head 133 at the tip near the air bearing surface F. The optical head 133 includes a light propagation layer 134 that emits irradiation light from the air bearing surface F, and a light deflection layer 135 that deflects the propagated irradiation light toward the light propagation layer 134.

  The light propagation layer 134 is a portion where a part in the thickness direction of the core layer 131 is exposed to the air bearing surface F near the main magnetic pole surface E which is one of both surfaces of the core layer 131. The light deflection layer 135 is a portion obtained by removing the light propagation layer 134 from the core layer 131, and is a portion closer to one surface opposite to the main magnetic pole surface E of the core layer 131. The light deflection layer 135 has a multilayer structure, and deflects light toward the light propagation layer 134 using a difference in refractive index between the layers. The air bearing surface F side of the light deflection layer 135 is covered with a light shield 136. The light deflection layer 135 is adjusted in the refractive index difference between the respective layers and the length and thickness of the light deflection layer 135 itself, whereby the incident angle and the incident position with high coupling efficiency in the light emitted from the light propagation layer 134 are adjusted. To control. Each layer of the light deflection layer 135 is formed of a material having a relatively high refractive index on the layer close to the light propagation layer 134, and a layer having a relatively low refractive index on a layer far from the light propagation layer 134. Is formed. For example, the same Ta 2 O 5 as that of the core can be used as the material of the layer closer to the light propagation layer 134. In addition, for example, SiO 2 can be used as the material of the layer far from the light propagation layer 134.

  When the thickness of the core layer 131 is as thin as the wavelength of light to be used, the light deflection layer 135 can employ a single layer structure of Ta 2 O 5 in addition to the above-described multilayer structure. In the case of a single layer structure, the light deflection layer 135 can be formed simultaneously with the core layer 131.

The light propagation layer 134 has a multilayer structure with a thickness equal to or less than a sub-wavelength which is about one-tenth of the wavelength of light to be used, and has a narrow width in the cross-track direction C as it approaches the air bearing surface F. Has a tapered shape. Out of each layer, the outer layer is formed of a material having a significant value for the extinction coefficient (k) in the complex refractive index (n ^* = n−jk). As the material of the outer layer, for example, a dielectric having a high relative dielectric constant (ε) such as Si or Ge, or a metal having a low relative dielectric constant (ε) such as Al, Au, or Cu can be used. In addition, among the layers, at least one of the inner layers is formed of a material that does not have a significant value for the absorption coefficient (k) in the complex refractive index, that is, is transparent to the wavelength of light to be used. As the material of the inner layer, for example, a material such as Ta2O5 or TiO2 is employed. With the multilayer structure, light propagating through the light propagation layer 134 is confined in the transparent inner layer, and light leakage to the main pole 121 is reduced.

  The light shield 136 prevents the light that could not be deflected by the light deflection layer 135 to the light propagation layer 134 from being emitted from the air bearing surface F and heating a non-target location of the magnetic disk 2. The light shield 136 covers the air bearing surface F side of the light deflection layer 135 and has a shape that spreads along the air bearing surface F. The light shield 136 also functions as a sub magnetic pole in this embodiment, but the function as the sub magnetic pole will be described later.

  The recording element 12 generates a layer-shaped main magnetic pole 121 that induces a magnetic force to act on the magnetic disk 2, a connection portion 123 that connects the optical shield 136 that functions as a sub magnetic pole and the main magnetic pole 121, and a magnetic field for recording. A thin film coil 124 and a heat dissipating portion 125 are provided. The main magnetic pole 121, the light shield 136 functioning as a sub magnetic pole, and the connection portion 123 constitute a part of a magnetic path of a magnetic flux generated during magnetic recording. The thin film coil 124 is arranged so as to be linked to this magnetic path. The magnetic head 100 is a perpendicular magnetic recording type magnetic head, and recording is performed on the magnetic disk 2 at a position on the trailing side of the main magnetic pole 121, that is, on the downstream side in the track direction T.

  The main magnetic pole 121 is formed on the main magnetic pole surface E side of the core layer 131, and is arranged side by side in the track direction T with the light propagation layer 134. Hereinafter, the direction in which the main magnetic pole 121 and the light propagation layer 134 are aligned is also referred to as a track direction T, and the direction that intersects the direction in which the main magnetic pole 121 and the light propagation layer 134 are aligned is also referred to as a cross track direction C. The main magnetic pole 121 is spaced apart from the core layer 131 and extends toward the air bearing surface F in parallel with the core layer 131. The main magnetic pole 121 extends obliquely toward the air bearing surface F while approaching the core layer 131 at a portion near the air bearing surface F. The vicinity of the surface F is in contact with the core layer 131 and exposed to the air bearing surface F. A portion of the main magnetic pole 121 that is separated from the core layer 131 and extends in parallel with the core layer 131, a portion that extends obliquely, and a portion that contacts the core layer 131 are parallel portions 121 a, skew portions 121 b, and contacts, respectively. This will be referred to as a part 121c. The parallel part 121a and the skew part 121b are arranged with the clad layer 132 interposed between the core layer 131 and the parallel part 121a. The parallel part 121a occupies most of the main magnetic pole 121 extending toward the air bearing surface F.

  The main magnetic pole 121 is made of a highly saturated magnetization material. As the material of the main magnetic pole 121, a monoatomic material such as Fe or Co or an alloy material such as FeCo can be used. The main magnetic pole 121 may have a single layer structure or a multilayer structure. A magnetic material having a high saturation magnetization adopted for the main magnetic pole 121 generally has an effective refractive index of n> 2, and is equal to or higher than the refractive index of the core layer 131 used in the optical waveguide. The refractive index is

  Here, if it is assumed that the main magnetic pole 121 has a structure extending straight to the air bearing surface F while being in contact with the core layer 131, the light propagating through the core layer 131 has a higher refractive index than the core layer 131. And is absorbed by the main magnetic pole 121. As a result, not only the light irradiated from the air bearing surface F toward the magnetic disk is attenuated, but also the magnetic force is reduced because the main pole is heated by the absorbed light.

  On the other hand, the main magnetic pole 121 of this embodiment is in contact with the core layer 131 only at the contact portion 121c exposed to the air bearing surface F. Neither the parallel part 121 a nor the skew part 121 b is in contact with the core layer 131, and the main magnetic pole 121 is disposed with the cladding layer 132 sandwiched between the main magnetic pole 121 and the core layer 131. For this reason, attenuation of light is suppressed. Further, a decrease in magnetic force due to heating of the main magnetic pole 121 can be suppressed. Further, the main magnetic pole 121 is adjacent to the light propagation layer 134 of the core layer 131 at the contact portion 121c exposed to the air bearing surface F, and the light spot by the emitted light is within the range covered by the magnetic field from the main magnetic pole 121 and the recording. It will overlap to a sufficient extent.

The light shield 136 in this embodiment also functions as a sub-magnetic pole, and forms a path for returning the magnetic flux that has exited from the main magnetic pole 121 and passed through the magnetic disk 2. When a recording current flows through the thin film coil 124, a magnetic path is formed in the main magnetic pole 121, the magnetic disk 2, the optical shield 136 that functions as a sub magnetic pole that surrounds the thin film coil 124, and the connection portion 123. Information is recorded by the vertical component of the magnetic field from the main pole 121 toward the magnetic disk 2. Here, with respect to the basic form described above, “the main body is provided with a light shielding portion that covers the tip of the light deflection layer on the air bearing surface side and prevents the transmission of the irradiation light, and the light shielding portion is formed of a magnetic material. The application form that “the magnetic force output from the magnetic pole also serves as the auxiliary magnetic pole to which the magnetic force returns” is suitable. The light deflection layer is placed on the opposite side of the main magnetic pole with the light propagation layer in between. The light shielding part that covers the air bearing surface of the light deflection layer also serves as the sub magnetic pole. The layers are arranged at an appropriate distance for forming a magnetic path in the storage medium. Further, the process of forming the magnetic head is simplified. The light shield 136 corresponds to an example of a light shielding unit in the application mode. The light shield 136 is preferably formed of a material having a significant value for the extinction coefficient (k) of the complex refractive index (n ^* = n−jk) with respect to the wavelength used, and in this embodiment, the magnetic shield 136 is magnetic. It is desirable to be formed of a material. Examples of the material of the light shield 136 include Fe (n ^* = 3.31-3.75j), Co (n ^* = 2.28-4.17j), and Nd (n ^* = 0.34-1.34j). Etc.) and these alloys can be used.

  The heat radiating part 125 is a member for radiating the heat generated in the main magnetic pole 121 to the periphery. The heat radiating portion 125 extends in the cross-track direction C and parallel to the air bearing surface F on both sides of the tip of the main magnetic pole 121. Specifically, the contact portion of the main magnetic pole 121 in contact with the light propagation layer 134 It extends on both sides of 121c. More specifically, the heat radiating portion 125 has a columnar shape extending in the cross track direction C, and has a structure in which the contact portion 121c is buried in the center portion. The contact part 121c is in contact with the light propagation layer 134, and a part of the light propagated in the light propagation layer 134 is absorbed. Since heat generated by light absorption is radiated to the outside of the contact part 121 c by the heat radiating part 125, a decrease in magnetic force due to a temperature rise of the main magnetic pole 121 is suppressed. The heat radiating portion 125 is made of a nonmagnetic material having a higher thermal conductivity than the surroundings. Examples of the material of the heat dissipation part 125 include Al (= 237 W / (m · K)), Au (= 317 W / (m · K)), Cu (= 401 W / (m · K)), and these. And Si (= 148 W / (m · K)) can be employed.

  The magnetic head 100 shown in FIGS. 2 to 4 is manufactured by repeatedly laminating each material and selectively etching the substrate by a known method. The oblique portion 121b of the main magnetic pole 121 has a shape extending obliquely toward the air bearing surface F. This portion covers the region below the main magnetic pole 121 other than the region where the skewed portion 121b is formed with a resist film or the like, and after the lower layer is cut obliquely by, for example, ion milling or FIB (Focused Ion Beam). It is formed by removing the resist film and laminating a magnetic material.

  The heat dissipating part 125 is formed of a nonmagnetic material having a higher thermal conductivity than the surroundings, and may be formed of a nonmagnetic material having a refractive index equal to or higher than the refractive index of the material of the main magnetic pole 121. More preferable in terms of refractive index distribution. As such a material, for example, Si (= 148 W / (m · K)) can be employed.

  Here, the refractive index distribution will be described. The main magnetic pole 121 is adjacent to the light propagation layer 134 in the vicinity of the air bearing surface F. The main magnetic pole 121 is made of a magnetic material and has a higher refractive index than the light propagation layer 134. Here, if a material having a lower refractive index than that of the light propagation layer 134 is used as the material of the heat dissipation part 125, the distribution of the refractive index in the cross-track direction C and the track direction T around the main magnetic pole 121 is seen. The distribution of the refractive index is high at the position of the main magnetic pole 121. Since the light propagation layer 134 is adjacent to the main magnetic pole 121 within this refractive index distribution, the effective refractive index of the portion close to the main magnetic pole 121 in the same layer of the light propagation layer 134 is high and the other portions are low. This produces an uneven distribution. The light propagation layer 134 confines and propagates light by the layer structure laminated in the track direction T. However, when the effective refractive index distribution inside becomes uneven, the light propagated in the light propagation layer 134 Since the tendency to deflect obliquely with respect to the stacking direction toward the center of the main magnetic pole 121 corresponding to the refractive index peak increases, the light propagation control by the layer structure is hindered.

  In the magnetic head 100 of this embodiment, the heat radiating portion 125 is formed of a nonmagnetic material having a refractive index equal to or higher than the refractive index of the material of the main pole 121, so that the position of the main pole 121 in the track direction T is achieved. The refractive index distribution as viewed in the cross-track direction C is uniform. Therefore, loss of light propagated in the light propagation layer 134 can be suppressed.

  This is in contrast to the basic form described above, "the direction in which the main magnetic pole and the light propagation layer are aligned is crossed and extends on both sides of the tip of the main magnetic pole in parallel with the air bearing surface. This means that an application mode including a refractive index correction unit formed of a nonmagnetic material having a refractive index equal to or higher than the refractive index of the material of the main magnetic pole is preferable. Here, the heat dissipation unit 125 of the first embodiment corresponds to an example of the refractive index correction unit of the application mode.

  In addition, an application mode in which the “refractive index correction unit also serves as a heat dissipation unit formed of a material having higher thermal conductivity than the surroundings” is suitable for the basic mode described above. When the refractive index correction unit also serves as the heat radiating unit, the heat of the main magnetic pole is efficiently radiated to both sides by the structure of the refractive index correction unit extending on both sides of the main magnetic pole, and the decrease in magnetic force is suppressed.

  In addition, for the basic form described above, “the light propagation layer near the one surface that emits irradiation light from the air bearing surface exposed to the air bearing surface at the tip portion near the air bearing surface of the core layer, and the tip portion Of the core layer, excluding the light propagation layer, and the portion of the core layer near the one surface opposite to the one surface, the light deflection for deflecting the transmitted irradiation light toward the light propagation layer The "with layer" application is preferred. By setting the light propagation layer that emits the irradiation light to the one surface side where the main magnetic pole is formed, the inclination of the portion in which the main magnetic pole extends obliquely can be made gentler than in the case of the opposite side.

[Modification]
In the first embodiment described above, the configuration of the magnetic head 100 in which the reproducing element 11, the main magnetic pole 121, the light propagation layer 134, and the optical shield 136 are sequentially arranged in the track direction T has been described. The magnetic heads may be arranged in another order. Next, a modification in which the arrangement order is different from that of the first embodiment will be described. These modifications have the same structure as the main structure of the magnetic head 100 shown in FIG. Accordingly, elements that are the same as those in the embodiment will be omitted or denoted by the same reference numerals, and differences from the first embodiment will be described.

  5 and 6 are cross-sectional views showing modifications in which the arrangement of each element is different from the magnetic head shown in FIGS.

  In the magnetic head 200 shown in FIG. 5, the reproducing element 21, the light shield 236, the light propagation layer 234, and the main magnetic pole 221 are sequentially arranged in the track direction T. The magnetic head 200 is an in-plane recording magnetic head, and recording is performed on the magnetic disk 2 at a position on the leading side of the main magnetic pole 221, that is, on the upstream side in the track direction T. The light propagation layer 234 is disposed on the leading side of the main magnetic pole 221, and a heat spot is generated in an area where recording is performed on the magnetic disk 2.

In the magnetic head 300 shown in FIG. 6, the light shield 336 and the sub magnetic pole 322 are formed of different members. The magnetic head 300 is a single magnetic pole type perpendicular magnetic recording type magnetic head, and in the track direction T, a reproducing element 31, a sub magnetic pole 322, a main magnetic pole 321, a light propagation layer 334, and a light shield 336 are arranged in this order. . The light shield 336 does not function as a magnetic pole but is a member that shields light. Therefore, the light shield 336 is not limited to a magnetic material, and is not magnetic as long as it has a significant value for the extinction coefficient (k) of the complex refractive index (n ^* = n−jk) at the wavelength of the light used. It can be made of a material. Examples of the material of the light shield 336 in the magnetic head 300 include Si (n ^* = 4.22-1.46j), Ge (n ^* = 4.89-1.46j), Ta (n ^* = 1.35). -2.6j), Cu (n ^* = 0.14-3.67j), Au (n ^* = 0.10-3.81j), Al (n ^* = 1.35-7.09j), nonmagnetic Materials, Fe (n ^* = 3.31-3.75j), Co (n ^* = 2.28-4.17j), Nd (n ^* = 0.34-1.34j), and alloys thereof Magnetic materials can be used.

[Second Embodiment]
In the above-described embodiment, the example in which the refractive index distribution is adjusted by forming the heat radiating portions extending on both sides of the main pole in the cross-track direction C with a material having a high refractive index has been described. Next, a specific second embodiment of the magnetic head in which the heat dissipation portion can be formed of a low refractive index material will be described. In the following description of the second embodiment, the same reference numerals are given to the same elements as those in the embodiments described so far, and differences from the above-described embodiments will be described.

  FIG. 7 is a view of a second embodiment of the magnetic head as viewed from the magnetic disk side.

In the magnetic head 400 shown in FIG. 7, the light propagation layer 434 and the main magnetic pole 421 are close to each other but not in contact with the magnetic head 100 of the first embodiment shown in FIGS. And the main magnetic pole 421 are different in that a refractive index correction layer 437 is provided. The refractive index correction layer 437 is a layer made of a nonmagnetic material having a high refractive index and having a length in the cross track direction C longer than that of the main magnetic pole 421. As a material of the refractive index correction layer 437, for example, Si or Ge (= 60 W / (m · K), n ^* = 4.89-1.46j) can be employed.

  According to the magnetic head 400, the refractive index distribution as viewed in the cross-track direction C is equalized by the refractive index correction layer 437 regardless of the material of the heat dissipation part 425. Therefore, loss of light propagated in the light propagation layer 134 can be suppressed. The material of the heat radiation part 425 in the magnetic head 400 of the second embodiment is not limited to Si having a high refractive index, and Al, Au, Cu, and alloys thereof having a higher thermal conductivity than the surrounding members but a lower refractive index, etc. A wide range of materials can be used. This is because the refractive index correction unit formed of a nonmagnetic material having a refractive index equal to or higher than the refractive index of the material of the main magnetic pole is provided between the main magnetic pole and the light propagation layer. The “with” application means that it is preferred. The refractive index correction layer 437 of the second embodiment corresponds to an example of a refractive index correction unit in this application mode.

[Third Embodiment]
Next, a specific third embodiment of the magnetic head in which high refractive index members are arranged on both sides of the light propagation layer in the cross track direction will be described. In the following description of the third embodiment, the same reference numerals are given to the same elements as those in the embodiments described so far, and differences from the above-described embodiments will be described.

  FIG. 8 and FIG. 9 are diagrams showing a specific third embodiment of the magnetic head. 8 is a view of the magnetic head as viewed from the magnetic disk side, and FIG. 9 is a cross-sectional view showing a cross section including the light propagation layer and extending in the cross track direction.

  The magnetic head 500 shown in FIGS. 8 and 9 includes a refractive index correction unit 537 extending on both sides of the light propagation layer in the cross-track direction C. The refractive index correction unit 537 is formed along both side edges 134 a of the tapered light propagation layer 134. The refractive index correction unit 537 is formed of a material that is equal to or higher in refractive index than the material of the main magnetic pole 121. As a material for the refractive index correction unit 537, for example, Si or Ge can be used for a non-magnetic material. From the viewpoint of heat dissipation, Si is more preferable. If the magnetic material is not in contact with the main magnetic pole, it can be used as one end of the magnetic path by connecting to the light shield 136 that also serves as the auxiliary magnetic pole. Alternatively, it can be used as a side seal for reducing an extra magnetic field from the main magnetic pole. As the magnetic material, Fe, Co, and alloys thereof can be used.

  According to the magnetic head 500 shown in FIGS. 8 and 9, the high refractive index main pole 121 is in contact with the track direction T of the light propagation layer 134, but the high refractive index correction is also performed on both sides in the cross track direction C. It is in contact with the part 537. For this reason, the symmetry of the refractive index distribution in the vicinity of the light propagation layer 134 on the air bearing surface F increases, and the loss of light is suppressed.

This is because, with respect to the basic form described above, “the main magnetic pole and the light propagation layer are aligned in an intersecting direction and parallel to the air bearing surface and extending on both sides of the light propagation layer. Application mode including a refractive index correction unit formed of a nonmagnetic material having the same or higher refractive index than that of the magnetic pole material, and “the light propagation layer becomes narrower as it approaches the air bearing surface. It has a tapered shape,
This means that the refractive index correction unit is preferably formed along both side edges of the tapered light propagation layer.

[Fourth Embodiment]
Next, a specific fourth embodiment of the magnetic head in which the light shield is composed of portions having different refractive indexes will be described. In the following description of the fourth embodiment, the same reference numerals are given to the same elements as those in the embodiments described so far, and differences from the above-described embodiments will be described.

  FIG. 10 is a diagram showing a specific fourth embodiment of the magnetic head.

  In the magnetic head 500 shown in FIG. 10, a portion P adjacent to the light propagation layer 134 in the light shield 536 is formed of a material having the same or higher refractive index than the material of the main magnetic pole 121. The light shield 536 also functions as a sub magnetic pole.

  More specifically, the light shield 536 has a low refractive index portion 536b near the main magnetic pole 121 in the track direction T and a high refractive index portion 536a near the opposite side. The high refractive index portion 536 a has a convex portion P that protrudes toward the light propagation layer 134 at the position of the light propagation layer 134 in the cross track direction C and is in contact with the light propagation layer 134. The width of the protrusion P in the cross track direction C is formed to be substantially the same as that of the main magnetic pole 121. The low refractive index portion 536b has a strip shape extending on both sides of the convex portion P in the cross track direction C. As the material of the high refractive index portion 536a, the same Fe or Co as the main magnetic pole 121, or an alloy material such as FeCo can be used. Further, Au or Cu can be used as the material of the low refractive index portion 536b.

  In the magnetic head 500, the main magnetic pole 121 and the high refractive index portion 536a both having high refractive indexes are in contact with both sides of the light propagation layer 134 in the track direction T, and the high refractive index portion 536a in the cross track direction C is in contact with each other. On both sides, low refractive index portions 536b having a low refractive index are arranged. Thereby, even when a low refractive index material is adopted as the material of the heat radiation part 525, the symmetry of the refractive index distribution in the vicinity of the light propagation layer 134 is enhanced. That is, the peak of the refractive index distribution can be avoided from being concentrated on one place of the main magnetic pole 121 having a finite width in the cross track direction C. Therefore, the loss of light can be suppressed.

[Fifth Embodiment]
Next, a specific fifth embodiment of the magnetic head, in which the shape of the light shield is different from the fourth embodiment described above, will be described. In the description of the fifth embodiment below, the same reference numerals are given to the same elements as those in the embodiments described so far, and differences from the above-described embodiments will be described.

  FIG. 11 is a diagram showing a specific fifth embodiment of the magnetic head.

  In the magnetic head 600 shown in FIG. 11, the portion P adjacent to the light propagation layer 134 in the optical shield 636 is equal to or higher than the refractive index of the material of the main magnetic pole 121, as in the magnetic head 500 shown in FIG. Formed of rate material. The light shield 636 also functions as a sub magnetic pole. However, the high refractive index portion 636b of the light shield 636 is limited to the portion in contact with the light propagation layer 134, and the rest is occupied by the low refractive index portion 636a. Accordingly, the high refractive index portion 636b is surrounded by the low refractive index portion 636a except for a portion adjacent to the light propagation layer 134.

  Similar to the magnetic head 500, the magnetic head 600 is in contact with the main magnetic pole 121 and the high refractive index portion 636b, both of which have a high refractive index, on both sides of the light propagation layer 134 in the track direction T. A low refractive index portion 636a having a low refractive index is disposed on both sides of the high refractive index portion 636b. Thereby, even when a low refractive index material is adopted as the material of the heat radiation part 625, the symmetry of the refractive index distribution in the vicinity of the light propagation layer 134 is enhanced, and the loss of light is suppressed.

  This means that for an application having a light-shielding portion, “the light-shielding portion is adjacent to the light propagation layer and is formed of a material having a refractive index equal to or higher than that of the material of the main magnetic pole. This means that the application form “with” is preferred. Here, each of the high refractive index portion 536a in the fourth embodiment and the high refractive index portion 636b in the fifth embodiment corresponds to an example of an adjacent portion in this application mode.

[Sixth Embodiment]
Next, a specific sixth embodiment of the magnetic head including a plasmon generating element instead of the light propagation layer will be described. In the following description of the sixth embodiment, the same reference numerals are given to the same elements as those in the embodiments described so far, and differences from the above-described embodiments will be described.

  FIG. 12 is a diagram showing a specific sixth embodiment of the magnetic head.

  A magnetic head 700 shown in FIG. 12 includes a plasmon generating element 734 instead of the light propagation layer. The plasmon generating element 734 is made of a metal material that easily causes the plasmon effect, for example, Cu / Ta 2 O 5, and has a tapered shape that becomes narrower as the air bearing surface F is approached, similar to the light propagation layer described so far. is doing. Further, the magnetic head 700 requires a heat radiating portion 725 for releasing heat accompanying light absorption into the main magnetic pole 121. The heat radiating portion 725 is a refractive index correcting portion formed of a high refractive index material. It is preferable to serve as both. In this case, as a material of the heat radiation part 725, a nonmagnetic material having high thermal conductivity, for example, Au, Cu or the like can be adopted in the case of a monoatomic material.

  In the above description of each specific embodiment, a magnetic disk is shown as an example of the storage medium in the basic mode described in “Means for Solving the Problems”. Alternatively, a magneto-optical disk may be used. Further, the embodiments can be combined.

  Hereinafter, the following additional notes will be disclosed with respect to various forms including the basic form and the application form described above.

(Appendix 1)
A magnetic head having a layer structure, the air bearing surface formed by one end surface of the layer structure is levitated toward a relatively moving storage medium, and information is magnetically recorded on the storage medium,
A core layer and a clad layer, extending toward the air bearing surface and being close to one of both surfaces of the core layer, a portion of the core layer in the thickness direction is exposed to the air bearing surface and irradiates the storage medium An optical waveguide that propagates the irradiated light and exits from the air bearing surface;
A main magnetic pole having a layer shape for guiding a magnetic force for recording information on the storage medium to act on the storage medium, the main pole being formed on the one surface side of the core layer and spaced apart from the core layer. Extending toward the air bearing surface in parallel with the layer, extending obliquely toward the air bearing surface while approaching the core layer at a portion near the air bearing surface, and the vicinity of the air bearing surface is in contact with or close to the core layer. A magnetic head having a main magnetic pole exposed on the air bearing surface.

(Appendix 2)
Excluding the light propagation layer near the one surface, which is exposed on the air bearing surface and emits irradiation light from the air bearing surface, and the light propagation layer in the tip portion of the core layer near the air bearing surface. And an optical deflecting layer configured to deflect the irradiated irradiation light toward the light propagating layer, which is composed of a portion of the both sides of the core layer that is closer to the one surface opposite to the one surface. The magnetic head according to appendix 1.

(Appendix 3)
The direction in which the main magnetic pole and the light propagation layer are aligned is an intersecting direction and extends to both sides of the front end of the main magnetic pole in parallel with the air bearing surface, and is equal to or higher than the refractive index of the material of the main magnetic pole. The magnetic head according to appendix 1 or 2, further comprising a refractive index correction unit made of a nonmagnetic material having a refractive index.

(Appendix 4)
The direction in which the main magnetic pole and the light propagating layer are aligned intersects and extends to both sides of the front end of the main magnetic pole in parallel with the air bearing surface, and is formed of a material having higher thermal conductivity than the surroundings. The magnetic head according to appendix 3, wherein the magnetic head is provided with a heat radiating portion.

(Appendix 5)
The direction in which the main magnetic pole and the light propagation layer are aligned intersects and extends to both sides of the light propagation layer in parallel with the air bearing surface, and is equal to or higher than the refractive index of the material of the main magnetic pole. 5. The magnetic head according to any one of appendices 1 to 4, further comprising a refractive index correction unit formed of a refractive index material.

(Appendix 6)
The light propagation layer has a tapered shape that becomes narrower as it approaches the air bearing surface,
6. The magnetic head according to claim 5, wherein the refractive index correction unit is formed along both side edges of the tapered light propagation layer.

(Appendix 7)
Additional remark 1 characterized in that a refractive index correction portion made of a nonmagnetic material having a refractive index equal to or higher than that of the material of the main magnetic pole is provided between the main magnetic pole and the light propagation layer. 6. The magnetic head according to any one of items 6.

(Appendix 8)
A light shielding part that covers the air bearing surface side tip of the light deflection layer and prevents transmission of the irradiation light;
The magnetic head according to any one of appendices 1 to 7, wherein the light-shielding portion also serves as a sub-magnetic pole made of a magnetic material and returning a magnetic force output from the main magnetic pole.

(Appendix 9)
9. The magnetic head according to claim 8, wherein the light shielding portion includes an adjacent portion that is adjacent to the light propagation layer and is formed of a material having a refractive index equal to or higher than that of the material of the main magnetic pole. .

(Appendix 10)
A storage medium on which information is magnetically recorded;
A magnetic head that has a layer structure and floats an air bearing surface composed of one end face of the layer structure toward the relative moving storage medium, and magnetically records information on the storage medium;
The magnetic head is
A core layer and a clad layer, extending toward the air bearing surface and being close to one of both surfaces of the core layer, a portion of the core layer in the thickness direction is exposed to the air bearing surface and irradiates the storage medium An optical waveguide that propagates the irradiated light and exits from the air bearing surface;
A main magnetic pole having a layer shape for guiding a magnetic force for recording information on the storage medium to act on the storage medium, the main pole being formed on the one surface side of the core layer and spaced apart from the core layer. Extending toward the air bearing surface in parallel with the layer, extending obliquely toward the air bearing surface while approaching the core layer at a portion near the air bearing surface, and the vicinity of the air bearing surface is in contact with or close to the core layer. And a main magnetic pole exposed on the air bearing surface.

(Appendix 11)
Excluding the light propagation layer near the one surface, which is exposed on the air bearing surface and emits irradiation light from the air bearing surface, and the light propagation layer in the tip portion of the core layer near the air bearing surface. And an optical deflecting layer configured to deflect the irradiated irradiation light toward the light propagating layer, which is composed of a portion of the both sides of the core layer that is closer to the one surface opposite to the one surface. The magnetic disk device according to appendix 10.

(Appendix 12)
The direction in which the main magnetic pole and the light propagation layer are aligned is an intersecting direction and extends to both sides of the front end of the main magnetic pole in parallel with the air bearing surface, and is equal to or higher than the refractive index of the material of the main magnetic pole. 12. The magnetic disk drive according to appendix 10 or 11, further comprising a refractive index correction unit made of a nonmagnetic material having a refractive index.

(Appendix 13)
The direction in which the main magnetic pole and the light propagating layer are aligned intersects and extends to both sides of the front end of the main magnetic pole in parallel with the air bearing surface, and is formed of a material having higher thermal conductivity than the surroundings. The magnetic disk device according to appendix 10, wherein the magnetic disk device includes a heat radiating portion.

(Appendix 14)
The direction in which the main magnetic pole and the light propagation layer are aligned intersects and extends on both sides of the light propagation layer in parallel with the air bearing surface, and is equal to or higher than the refractive index of the material of the main magnetic pole. 14. The magnetic disk device according to any one of appendices 10 to 13, further comprising a refractive index correction unit made of a material having a refractive index.

(Appendix 15)
The light propagation layer has a tapered shape that becomes narrower as it approaches the air bearing surface,
15. The magnetic disk device according to appendix 14, wherein the refractive index correction unit is formed along both side edges of the tapered light propagation layer.

(Appendix 16)
Additional remark 10 characterized in that a refractive index correction portion formed of a nonmagnetic material having a refractive index equal to or higher than the refractive index of the material of the main magnetic pole is provided between the main magnetic pole and the light propagation layer. 15. The magnetic disk device according to any one of 15.

(Appendix 17)
A light shielding part that covers the air bearing surface side tip of the light deflection layer and prevents transmission of the irradiation light;
17. The magnetic disk device according to any one of appendices 10 to 16, wherein the light shielding portion also serves as a sub magnetic pole made of a magnetic material and returning a magnetic force output from the main magnetic pole.

(Appendix 18)
18. The magnetic disk according to claim 17, wherein the light shielding portion includes an adjacent portion that is adjacent to the light propagation layer and is formed of a material having a refractive index equal to or higher than that of the material of the main magnetic pole. apparatus.

1 is a diagram illustrating a specific embodiment of a magnetic disk device. 1 is a perspective view showing a specific embodiment of a magnetic disk device. 1 is a cross-sectional view showing a specific embodiment of a magnetic disk device. It is the figure which looked at concrete embodiment of the magnetic disc unit from the magnetic disc side. FIG. 5 is a cross-sectional view illustrating a modification in which the arrangement of each element is different from that of the magnetic head illustrated in FIGS. FIG. 5 is a cross-sectional view showing another modification example in which the arrangement of each element is different from the magnetic head shown in FIGS. It is the figure which looked at concrete 2nd Embodiment of the magnetic head from the magnetic disk side. It is the figure which looked at concrete 3rd Embodiment of the magnetic head from the magnetic disk side. It is sectional drawing which shows specific 3rd Embodiment of a magnetic head. It is a figure which shows specific 4th Embodiment of a magnetic head. It is a figure which shows specific 5th Embodiment of a magnetic head. It is a figure which shows specific 5th Embodiment of a magnetic head.

Explanation of symbols

1 Magnetic disk device 2 Magnetic disk (storage medium)
100, 200, 300, 400, 500, 600, 700 Magnetic head 11, 21, 31 Playback element 12 Recording element 121, 221, 321, 421 Main magnetic pole 125, 425, 525, 725 Heat radiation part 13 Optical waveguide 131 Core layer 132 Clad layer 134, 234, 334, 434 Light propagation layer 135 Light deflection layer 136, 236, 336, 536, 636 Light shield (light shielding layer, sub magnetic pole)
536a, 636a High refractive index part (adjacent part)
E Main magnetic pole surface (one surface)
F Air bearing surface T Track direction C Cross track method

Claims (10)

A magnetic head having a layer structure, the air bearing surface formed by one end surface of the layer structure is levitated toward a relatively moving storage medium, and information is magnetically recorded on the storage medium,
A core layer and a clad layer, extending toward the air bearing surface and being close to one of both surfaces of the core layer, a portion of the core layer in the thickness direction is exposed to the air bearing surface and irradiates the storage medium An optical waveguide that propagates the irradiated light and exits from the air bearing surface;
A main magnetic pole having a layer shape for guiding a magnetic force for recording information on the storage medium to act on the storage medium, the main pole being formed on the one surface side of the core layer and spaced apart from the core layer. Extending toward the air bearing surface in parallel with the layer, extending obliquely toward the air bearing surface while approaching the core layer at a portion near the air bearing surface, and the vicinity of the air bearing surface is in contact with or close to the core layer. A magnetic head having a main magnetic pole exposed on the air bearing surface.   Excluding the light propagation layer near the one surface, which is exposed on the air bearing surface and emits irradiation light from the air bearing surface, and the light propagation layer in the tip portion of the core layer near the air bearing surface. And an optical deflecting layer configured to deflect the irradiated irradiation light toward the light propagating layer, which is composed of a portion of the both sides of the core layer that is closer to the one surface opposite to the one surface. The magnetic head according to claim 1.   The direction in which the main magnetic pole and the light propagation layer are aligned is an intersecting direction and extends to both sides of the front end of the main magnetic pole in parallel with the air bearing surface, and is equal to or higher than the refractive index of the material of the main magnetic pole. The magnetic head according to claim 1, further comprising a refractive index correction unit made of a nonmagnetic material having a refractive index.   The direction in which the main magnetic pole and the light propagating layer are aligned intersects and extends to both sides of the front end of the main magnetic pole in parallel with the air bearing surface, and is formed of a material having higher thermal conductivity than the surroundings. The magnetic head according to claim 3, further comprising a heat radiating portion.   The direction in which the main magnetic pole and the light propagation layer are aligned intersects and extends to both sides of the light propagation layer in parallel with the air bearing surface, and is equal to or higher than the refractive index of the material of the main magnetic pole. 5. The magnetic head according to claim 1, further comprising a refractive index correction unit made of a material having a refractive index. The light propagation layer has a tapered shape that becomes narrower as it approaches the air bearing surface,
6. The magnetic head according to claim 5, wherein the refractive index correcting portion is formed along both side edges of the tapered light propagation layer.   2. A refractive index correction unit formed of a nonmagnetic material having a refractive index equal to or higher than a refractive index of a material of the main magnetic pole between the main magnetic pole and the light propagation layer. 7. A magnetic head according to any one of items 1 to 6. A light shielding part that covers the air bearing surface side tip of the light deflection layer and prevents transmission of the irradiation light;
8. The magnetic head according to claim 1, wherein the light-shielding portion also serves as a sub-magnetic pole made of a magnetic material and returning a magnetic force output from the main magnetic pole. 9.   9. The magnetism according to claim 8, wherein the light shielding portion includes an adjacent portion that is adjacent to the light propagation layer and is formed of a material having a refractive index equal to or higher than that of the material of the main magnetic pole. head. A storage medium on which information is magnetically recorded;
A magnetic head that has a layer structure and floats an air bearing surface composed of one end face of the layer structure toward the relative moving storage medium, and magnetically records information on the storage medium;
The magnetic head is
A core layer and a clad layer, extending toward the air bearing surface and being close to one of both surfaces of the core layer, a portion of the core layer in the thickness direction is exposed to the air bearing surface and irradiates the storage medium An optical waveguide that propagates the irradiated light and exits from the air bearing surface;
A main magnetic pole having a layer shape for guiding a magnetic force for recording information on the storage medium to act on the storage medium, the main pole being formed on the one surface side of the core layer and spaced apart from the core layer. Extending toward the air bearing surface in parallel with the layer, extending obliquely toward the air bearing surface while approaching the core layer at a portion near the air bearing surface, and the vicinity of the air bearing surface is in contact with or close to the core layer. And a main magnetic pole exposed on the air bearing surface.

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