KR100415421B1 - Textured magnetic recording medium having a transition zone - Google Patents

Abstract

The present invention relates to a magnetic recording medium provided with a textured surface comprising a landing area, a data area and a transition area having projections having a height and a diameter that are gradually reduced during progression from the landing area to the data area. The transition region can be formed by laser texturing and controlling the peak power of the pulsed laser beam and / or the rotational speed of the textured surface.

Description

TEXTURED MAGNETIC RECORDING MEDIUM HAVING A TRANSITION ZONE}

Magnetic disks and disk drives are commonly used to store data in magnetizable form. Typically, one or more discs are rotated on a central axis and generally moved in a radial direction with a data converter head located adjacent to the recording surface of the disc. Magnetic disks generally have a magnetic head having a specific load that is elastically in contact with the disk surface and is compressed and is contained within the magnetic disk unit in a stationary state.

In operation, the magnetic disk is generally driven in a Contact Start Stop (CSS) manner, and the head begins to slide on the disk surface as the disk begins to rotate. As soon as the preset high rotational speed is reached, the head floats in air at predetermined intervals from the disk surface due to the dynamic pressure effects caused by the air flow generated between the disk's sliding surface and the disk. In read and write operations, the transducer head is kept at a controlled distance from the recording surface and supported on the bearing of air while the disk is rotating. The magnetic head unit is arranged so that the head can move freely in both the circumferential direction and the radial direction of the disc in this floating state so that data can be recorded and retrieved on the disc at the desired position.

At the end of the operation of the disc drive, the rotational speed of the disc decreases and the head slides back to the disc surface and eventually stops to contact the disc and compress. Thus, the transducer head contacts the recording surface every time the disc is at rest, every time it is accelerated from the standstill and during deceleration just before it comes to a complete stop. Each time the head and disk assembly are driven, the sliding surface of the head repeats a periodic operation consisting of the steps of stopping, sliding the disk surface, floating in the air, sliding on the disk surface, and stopping.

It is considered desirable to keep each transducer head as close as possible to the associated recording surface during read and write operations, i.e. to minimize the lift height of the head. This purpose is particularly important as the area recording density increases. The area density (Mbit / in ² ) is the recording density per unit area and is equal to the product of the track density (TPI), which is a track per inch, and the linear density (BPI), which is bits per inch. Therefore, a flat opposite surface of the associated transducer head as well as a flat recording surface is preferred, whereby the head and disk can be positioned closer to each other with a concomitant increase in the coherent action and predictability of the air bearings supporting the head. do. However, other factors work against this purpose. If the head and recording surfaces are too flat, precise matching of these surfaces will cause excessive wear and friction during start and stop, thereby eventually causing wear to a condition called "head breakage" for the head and recording surface. Let's do it. Therefore, the objective of achieving reduced head / disk friction and minimum transducer lift height must be achieved.

To satisfy this conflicting purpose, the recording surface of the magnetic disk is provided with a rough surface to reduce head / disk friction by a technique commonly referred to as "texturing". Conventional texturing techniques provide disk substrates to provide texturing on top of subsequent layers deposition, such as underlayers that are typically chromium or chromium-alloy, magnetic layers, typically protective carbon overcoat and lubricant topcoats. Polishing the surface of the substrate, wherein the textured surface on the substrate is intended to be substantially replicated on the surface of the magnetic disk.

A typical magnetic recording medium is shown in FIG. 1, which shows a substrate 10 which is typically an aluminum-base alloy such as an aluminum-magnesium (Al-Mg) alloy plated with an amorphous nickel-phosphorus (NiP) layer. Include. Substrate 10 is generally a chromium (Cr) underlayer 11 deposited sequentially thereon, a magnetic layer 12, typically a cobalt (Co) group alloy, a protective overcoat 13, typically comprising carbon, and A lubricant top coating (14). The chromium (Cr) underlayer 11, cobalt (Co) -based alloy magnetic layer 12 and protective carbon overcoat 13 are typically deposited by sputtering techniques. Conventional Al-alloy substrates are provided with NiP plating to increase the hardness of the Al substrate, serving as a suitable surface to provide the required surface roughness or texture, which is substantially reproduced on the disk surface.

The requirement for incremental increase for high area recording density requires greater requirements on thin film magnetic media in terms of coercivity, squareness, low media noise and narrow track recording performance. In addition, increasing high density and large capacity magnetic disks require increasingly lower flight heights, ie the spacing of heads on the surface of the disk in CSS drives. The requirement to further reduce the height of rise of the head required by the increasingly high recording density and capacity makes it particularly difficult to meet the requirement for controlled texturing to prevent head breakage.

The conflicting requirements for the minimum transducer float height and texturing can be somewhat mitigated by providing separate landing areas and separate data areas. In this way, the surface of the data area can be best utilized for data storage and retrieval, while the landing area can be best utilized for texturing to meet CSS requirements. This textured surface comprising a head landing area and a data recording area is produced by first grinding the surface and then laser texturing to form the head landing area past the polished data area. However, the resulting surface contains undesired abrupt shape changes between the landing and data regions.

Sudden shape change on the surface of the magnetic recording medium adversely affects the floating stability and glide performance of the magnetic recording head and adversely affects the reliability of the head-medium interface. Moreover, such problematic local abrupt shape changes require more precise texturing.

Thus, texturing for high area recording densities including a landing area having a most utilized shape for data recording and retrieval and CSS operations, without abrupt shape changes between the data area and landing area. It is necessary to provide a finished surface.

The above techniques of the present invention can be easily understood in view of the following detailed description with reference to the drawings.

The present invention relates to the recording, storing and reading of magnetic data, in particular rotating magnetic recording media such as thin film magnetic disks having a textured surface for contact with a cooperating magnetic transducer head. The present invention relates in particular to a high density magnetic recording medium which exhibits low noise and has improved floating stability, glide performance and head-medium interface reliability.

1 shows a conventional magnetic recording medium structure.

2 schematically shows a multi-lens laser focusing system according to the present invention.

3 schematically illustrates a laser focusing system using a crystalline material according to the invention.

4 schematically shows a laser texturing system with a glass or glass-ceramic substrate.

5 schematically shows another laser texturing system with a glass or glass-ceramic substrate.

6 schematically illustrates a textured surface formed in accordance with the present invention.

It is an object of the present invention to provide a magnetic recording medium comprising a textured surface having a utilized data area optimized for recording and a landing area optimized for head landing, without a sudden shape change between the data area and the landing area. It is.

Another object of the present invention is to provide a method of texturing a magnetic recording medium to provide a data area optimized for recording and a landing area optimized for CSS performance, without a sudden shape change between the data area and the landing area. It is.

Additional objects, advantages and other features of the invention will be described below and will be understood by those skilled in the art from the following description or may be learned by practice of the invention. The objects and advantages of the invention will be realized and attained in particular by the appended claims.

In accordance with the present invention, the above and other objects include a textured area having a data area, a textured landing area having a plurality of protrusions extending substantially constant above the surface, and a textured transition area. Which is implemented by a magnetic recording medium, wherein the transition area has a plurality of protrusions having a height and a diameter that gradually decrease while traveling from the landing area to the data area.

Another aspect of the invention is directed to a method of manufacturing a magnetic recording medium, the method comprising forming a textured surface on a magnetic recording medium layer, the textured surface being substantially in the data area, on top of the surface. And a textured landing region having a plurality of protrusions extending at a constant height, and a laser textured transition region between the landing region and the data region, wherein the transition region gradually advances from the landing region to the data region. It has a plurality of protrusions with decreasing height and diameter.

Further objects and advantages of the invention will be readily apparent to those skilled in the art from the following detailed description, wherein the embodiments of the invention are concisely described by best contemplated examples for practicing the invention. As will be realized, the invention is capable of other and different embodiments, and its details may be modified in various obvious respects, all without departing from the scope of the invention. Accordingly, the drawings and detailed description are exemplary and should not be regarded as limiting of the invention.

The present invention addresses the conflicting requirements for reduced head / disk friction and minimum transducer lift height in addition to maximizing area recording density in conventional CSS systems. This conflicting requirement is solved by providing a magnetic recording medium having a textured surface having a landing area and a data area, each area being optimized for its particular function. However, the present invention goes one step further and addresses and solves the problems caused by providing a textured surface having an adjacent optimal landing area and an optimized data recording area.

Making the most of the texturized landing area for reduced head / disk friction forces and making the most of the data area for the minimum transducer lift height adjacent to the landing area on the same surface results in sudden shape profile changes. These abrupt shape changes require a great deal of precision in implementing CSS techniques.

The present invention seeks to address and solve this problem by providing a transition region between the landing region and the data region, where the shape of the transition region is designed to prevent sudden shape changes. According to the present invention, a transition region is provided between a textured landing region comprising a plurality of protrusions extending on the surface and a relatively flat data region on the surface, which transitions from the landing region to the relatively flat data region. A plurality of protrusions having a reduced height and diameter.

In various embodiments of the present invention, the surface of a magnetic recording medium, for example, a substrate or an underlying layer formed on the substrate, such as chromium or chromium-alloy, can be polished by conventional polishing techniques. The textured landing area may then be formed by conventional techniques such as mechanical polishing or laser texturing. Preferably, the landing area is laser textured to form a number of relatively constant protrusions that extend to a substantially constant height on the surface. Suitable laser texturing techniques are disclosed in co-pending application No. 08 / 666,374, wherein a multi-lens focusing system is used to accurately correct a substantially constant protrusion having a smaller size conveniently than that obtained with a conventional single lens focusing system. It is used to form a control pattern. Application No. 08 / 666,374 is hereby incorporated by reference.

Another suitable laser texturing technique for forming a landing area is disclosed in co-pending application No. 08 / 647,407, wherein the focused laser beam is a lens focusing system in order to obtain a number of controlled and precisely spaced overhangs. It passes between the photonic crystal material and a spaced distance between the laser textured surface. Application No. 08 / 647,407 is hereby incorporated by reference.

In addition, the landing region may be preferably formed by laser texturing using a technique combining application number 08 / 666,374 and application number 08 / 647,407, wherein the pulsed light emitted from the multi-lens focusing system The laser light beam passes through the surface to be laser textured through the photonic crystal material.

When using glass or glass-ceramic substrates, it is preferred to use the laser texturing technique disclosed in Application No. 08 / 666,373, which is incorporated herein by reference. Co-pending application number 08 / 666,373 uses a pulsed laser light source with a wavelength of approximately 10 μm, such as a laser light beam derived from a CO ₂ laser source, to laser the landing area onto a glass or glass-ceramic substrate. Techniques for texturing are disclosed.

When providing a landing area textured by laser texturing, the polished data area is left behind. In one embodiment of the invention, the data area may also be textured but the data area remains polished. After forming the landing region and the data region, the transition region of the present invention is formed. Laser texturing is a suitable technique for forming transition regions.

According to one embodiment of the invention, the surface is exposed to a rotating and pulsed laser light beam, preferably moving in the radial direction with respect to the data region starting at the landing region and starting at the end of the transition region. While exposing the surface to a pulsed laser light beam to form a transition region, factors affecting the shape of the protrusion are adjusted so that the protrusion has a spiraled reduced height and diameter as it progresses from the landing region to the data region. To form a transition region. Those skilled in the art will know the appropriate parameters and adjustments necessary to form a gradual transition region between the landing and data regions. For example, this controlled transition region is possible by controlling the emission of laser pulse power, laser pulse width and target movement. The height and diameter of the protrusions generated by pulsed laser light beam texturing decrease as the peak pulse power decreases and increase as the speed at which the surface rotates decreases.

The present invention preferably has a textured surface having three regions to be optimized to meet functional requirements for recording and CSS performance while preventing abrupt shape changes between them to improve the flexibility of the CSS process. Provide a magnetic recording medium. These three region texturing patterns can most preferably be laser textured using a computer-controlled laser beam combined with precision automated equipment. By controlling the emission of laser pulse power, laser pulse width and target movement, the desired profile of all three regions can be obtained for various head shapes.

The transition region of the present invention can be formed by conventional laser texturing techniques. Precisely designed transition regions can be formed using a multi-lens focusing system, as disclosed in co-pending application number 08 / 666,374, providing a substantially smaller size that is conveniently smaller than that obtained with conventional single lens focusing systems. This results in a precisely controlled pattern of constant protrusions.

In another embodiment of the present invention, the transition region is formed by the laser texturing technique disclosed in co-pending application number 08 / 647,407, wherein the focused laser light beam comprises a plurality of controlled and precisely spaced protrusions. In order to obtain a textured texture, it is interposed between the laser textured lens focusing system surfaces and passed through the photonic crystal material at regular intervals.

In another embodiment of the present invention, the transition region is formed by combining the multi-lens focusing system disclosed in co-pending application number 08 / 666,374 with the photonic crystal material disclosed in co-pending application number 08 / 647,407. According to this embodiment, the laser light beam focused by the multi-lens focusing system passes through the photonic crystal material and forms a transition region before impinging on the laser textured surface.

According to the invention, the manufacturing method is simplified and the workload is increased by laser texturing the landing and transition areas using the same form as the laser texturing system. According to the present invention, the data region may be left polished or textured by laser texturing techniques.

In one embodiment of the invention, the transition region and / or landing region may be laser textured using a multi-lens focusing system disclosed in co-pending application number 08 / 666,374 and shown in FIG. Includes a primary lens 20, such as a companion doublet, and a secondary lens 21, such as an aplanatic meniscus lens. The secondary lens 21 is positioned at regular intervals between the primary lens 20 and the rotating substrate 24, and the surface of the rotating substrate is laser textured. The primary lens 20 has a focal point indicated by reference numeral 23 on the upper surface of the substrate 24. However, the depth of focus of the multi lens focusing system is extended to the point 25 by the secondary lens 21. The increased depth of focus provides the desired flexibility, allowing the formation of protrusions with smaller heights and diameters with greater precision and uniformity compared to conventional single lens focusing systems. Clearly, providing increased depth of focus facilitates the adjustment and maintenance of the focus, thereby providing a tolerance that can accommodate inherent surface uniformity that was not possible with conventional single lens laser focusing systems.

In another embodiment of the invention, the transition and / or landing regions are laser texturized using a system disclosed in co-pending application number 08 / 647,407 and comprising a photonic crystal material such as shown in FIG. 3. Wherein the pulsed laser light beam 30 is focused through the lens 31. Photonic crystal material 32, which may include various photonic crystal materials such as calcite or quartz, is inserted in the path of the pulsed and focused laser light beam. The photonic crystal material 32 is selected to have a thickness d and a crystal-induced light access angle α, thereby forming two focal points p1 and p2 with different energy intensities. The focal points p1 and p2 are separated by a distance t which is a function of the crystal thickness d and the crystal-induced optical access angle α.

In another embodiment of the invention, the transition region and / or the landing region is a multi-lens focus system with a photonic crystal material positioned to pass through the photonic crystal material before the focused pulsed light beam impinges on a laser textured surface. Both are laser textured.

The laser texturing technique of the present invention can be used to texture a magnetic recording medium by impinging a focused laser beam on any layer of magnetic recording medium as well as a rotating substrate as in the embodiments described above. Thus, according to the invention, an underlayer or underlayer, such as a Cr or Cr-alloy underlayer, such as with a pulsed laser light beam passing through a multi-lens focusing system and / or a pulsed laser light beam passing through a photonic crystal material. A magnetic layer, such as a Co-alloy magnetic layer provided on the layer or a Co-alloy magnetic layer applied directly onto the substrate, may be laser textured to form transition and / or landing regions. A laser texturing pattern comprising three regions according to the present invention can be applied directly onto Al or Al-alloy substrates on such substrates after conventional Ni-P plating has been applied. The laser textured surface provided in accordance with the present invention can be substantially reproduced in later deposited layers.

Magnetic recording media made in accordance with the present invention may include any one of several conventional substrates used to make magnetic recording media. Such conventional substrates include Al, Al-alloys such as Al-Mg alloys, NiP plated AL or NiP plated Al-alloys. In addition, optional substrates such as glass or glass-ceramic materials can be used to form a textured surface comprising a landing area, a recording area and a transition area in accordance with the present invention.

In another embodiment of the present invention, a substrate comprising glass or glass-ceramic material is laser textured using a pulsed laser light beam as disclosed in co-pending application number 08 / 666,373 to transition zones, landings. Areas and data areas are formed.

It is shown schematically in the laser Texture ring system using a ceramic substrate 4, and is controlled by a controller (41) CO ₂ laser source powered by the generator 48 (-glass or glass according to the invention 40). The emitted laser light beam 42 is a glass or glass which is rotated by the spindle 47 through a shutter 43 and a light system 44 with mirrors 44a and 44b such as silicon mirrors and a pulsed laser light beam. Passing through a focusing lens 45 for focusing on the surface of the ceramic substrate 46. It is desirable to provide the lens 45 with a suitable coating such as lead selenide.

Another laser texturing system using a glass or glass-ceramic substrate is schematically illustrated in FIG. 5, where the laser light beam 51 generated by the CO ₂ laser source 52 comprises mirrors 53a and 53b. Is passed through a beam delivery system 53. The laser light beam 51 then reaches the beam splitter 57 through a modulator 54, a beam expander 55 comprising a concave lens 55a and a bichromatic lens 55b, and a polarization rotator 56 Here it is divided into components 51a and 51b. The laser light beam component 51a is focused on the first surface of the glass or glass-ceramic substrate 59 that passes through the diffractive focusing lens 58 and is rotated by the spindle 510. The laser light beam component 51b is reflected at mirrors 511a, 511b, 511c, such as silicon mirrors, and reaches on the opposite second surface of the substrate 59 through the second diffractive focusing lens 512. The diffractive focusing lenses 58, 512 are preferably coated with zinc selenide.

The laser texturing surface formed in accordance with the present invention is schematically illustrated in FIG. 6 and comprises a layer 60 composed of a magnetic recording medium. This layer may be a substrate, an underlayer formed on the substrate, or a magnetic layer. The textured surface of the present invention comprises three regions: a landing region, a transition region and a data region. The landing area includes a plurality of protrusions 61 extending at a substantially constant height on the textured surface. Although the data area 63 is shown polished, the data area 63 can also be laser textured, in which case the data area extends to a relatively constant height on the substrate surface but is significantly lower than the height of the protrusions in the landing area. And a groove pattern formed in the plurality of extending protrusions or the substrate. The transition region comprises a laser textured region having projections 62 having progressively decreasing heights and diameters from the landing region to the data region, thereby alleviating abrupt shape changes and the accompanying problems. .

The magnetic layer deposited according to the present invention may be any layer used in the manufacture of the magnetic recording medium. Such conventional magnetic alloys include cobalt-chromium (CoCr), cobalt-samarium (CoSm), cobalt-chromium-tantalum (CoCrTa), cobalt-nickel-chromium (CoNiCr), cobalt-chromium-samarium (CoCrSm), cobalt-chromium Such as -platinum-tantalum (CoCrPtTa), cobalt-chromium-platinum (CoCrPt), cobalt-nickel-platinum (CoNiPt), cobalt-nickel-chromium-platinum (CoNiCrPt) and cobalt-chromium-platinum-boron (CoCrPtB) (Co) -based alloys, including but not limited to. The thickness of the magnetic layer is consistent with the conventional practice and manufacture of magnetic recording media. Cobalt-based alloys having a thickness of approximately 100 kV to 1000 kV, such as 200 kV to 500 kV, are known to be suitable.

In a typical embodiment, the underlying layer may be deposited on a textured substrate prior to depositing the magnetic layer. The bottom layer may comprise chromium, or a chromium-vanadium or chromium-titanium, a Cr alloy such as oxygen-doped Cr, tungsten or a tungsten alloy.

In addition, a protective overcoat, such as carbon overcoat, may be deposited on the magnetic layer, and a lubricant topcoat may be deposited on the protective overcoat. The underlayer, magnetic layer and protective overcoat can be applied in a conventional manner by any of the various sputtering techniques used in the manufacture of magnetic recording media.

The present invention can be used to produce any of various types of magnetic recording media including thin film discs, with improvements shown in floating stability, sliding performance and head-medium interface reliability. According to the present invention, a magnetic recording medium is provided with a textured surface comprising a data area, a textured landing area having a plurality of protrusions extending at a substantially constant height on the surface, and a textured transition area, wherein the transition The region includes a plurality of protrusions having a progressively reduced height and diameter as it progresses from the landing region to the data region. The data regions may be polished or textured by mechanical texturing techniques. The landing area can also be textured by mechanical texturing or laser texturing. According to the present invention, the transition region is laser textured using a pulsed laser light beam, wherein the peak pulse power and / or the rotational speed of the substrate is of a height and diameter that spirally decreases during the data region in the landing region. The branches are varied to provide a plurality of protrusions. Typically, the landing region has a peak surface roughness Rp of approximately 15-20 nm, while the data region has a peak surface roughness Rp of approximately 2-3 nm.

Only a few embodiments of the invention have been shown and described herein. It is to be understood that the present invention can be used in various combinations and environments and that there are variations and modifications within the scope of the spirit of the invention shown herein.

Claims (20)

Data area; A laser textured magnetic head landing region having a first plurality of protrusions extending at a substantially constant height on the surface; And Having a surface comprising a laser textured transition region having a second plurality of protrusions having a smaller diameter and a height that decreases helically while traveling from the landing region to the data region, Wherein said landing region or transition region is laser textured by exposing a surface of a nonmagnetic substrate to a laser light beam having a constant wavelength. 2. The magnetic recording medium of claim 1, wherein the data area is polished or textured. 3. The magnetic recording medium of claim 2, wherein the data area is mechanically textured. 2. The magnetic recording medium of claim 1, wherein the landing region has a peak surface roughness (Rp) of 15 to 20 nm, and the data region has a peak surface roughness (Rp) of 2 to 3 nm. 2. The magnetic recording medium of claim 1, wherein the magnetic recording medium comprises a nonmagnetic substrate, a lower layer sequentially formed on the nonmagnetic substrate in the order of being cited, a magnetic layer, a protective overcoat and a lubricant topcoat, wherein the textured surface is A magnetic recording medium provided on an underlayer and reproduced on said sequentially deposited layer. A method of manufacturing a magnetic recording medium comprising a nonmagnetic substrate, a lower layer formed on the substrate, and a magnetic layer formed on the lower layer, Data area; A laser textured magnetic head landing region having a first plurality of protrusions extending at a substantially constant height on the surface; And The non-magnetic substrate may include a textured surface including a laser textured transition region having a second plurality of protrusions having a smaller diameter and a height that decreases helically while traveling from the landing region to the data region. Or forming on the surface of the underlying layer, Wherein said landing region or transition region is laser textured by exposing the surface of said nonmagnetic substrate to a laser light beam having a constant wavelength. 7. The method of manufacturing a magnetic recording medium according to claim 6, comprising the step of sequentially forming the data area, the landing area and the transition area in the order of being cited. The method of claim 7, wherein Polishing the surface; Laser texturing to form the landing area, leaving the polished data area; And And laser texturing to form the transition region. 7. The method of claim 6, further comprising laser texturing to form the transition region by exposing a surface between the landing region and the data region to a pulsed laser light beam having peak power while rotating the surface at a constant speed. A method of manufacturing a magnetic recording medium, comprising: 10. The magnetic recording medium of claim 9, comprising varying the peak power of the pulsed laser light beam and / or the rotational speed of the surface to adjust the height and diameter of the protrusions in the transition region. Manufacturing method. 11. The method of claim 10, reducing the peak power of the pulsed laser light beam and / or increasing the speed of the rotating surface while proceeding from the landing area to the data area to form the transition area. A method of manufacturing a magnetic recording medium, characterized by comprising the step of making. 7. The method of claim 6, comprising texturing the data area. 13. The method of manufacturing a magnetic recording medium according to claim 12, comprising mechanically texturing the data area. 7. The method of claim 6, comprising exposing the surface of the nonmagnetic substrate to a pulsed and focused laser light beam having a wavelength of about 10 microns to laser texturing the landing region and / or the transition region. A magnetic recording medium manufacturing method characterized by the above-mentioned. 7. The method of claim 6, wherein the pulse is through a multi-lens focusing system having a primary lens and a secondary lens positioned at regular intervals between the primary lens and an upper surface of the substrate to form a focused laser light beam. Exposing the surface to a laser light beam that has been laserized to laser texturing the landing region and / or the transition region. 7. The magnetic recording medium of claim 6 including passing a laser light beam focused through a photonic crystalline material through the laser textured surface to laser texturing the landing area and / or the data area. Manufacturing method. 16. The method of claim 15, comprising passing the focused laser light beam through a photonic crystal material inserted at regular intervals between the lens focusing system and the laser textured surface. Way. 15. The method of claim 14, further comprising: a multi-lens focusing system having a primary lens and secondary lenses positioned at regular intervals between the primary lens and an upper surface of the substrate to form a focused laser light beam. Exposing a top surface to the pulsed laser light beam. 19. The method of claim 18, further comprising passing the pulsed and focused laser light beam through a photonic crystal material inserted at regular intervals between the lens focusing system and the laser textured surface. Method of manufacturing magnetic recording medium. 15. The method of claim 14 including passing the pulsed and focused laser light beam through the photonic crystal material to the surface being laser textured.