JP4488236B2 - Magnetic recording medium manufacturing method and magnetic recording / reproducing apparatus - Google Patents

Description

  The present invention relates to a magnetic recording medium used in a hard disk device or the like, a manufacturing method thereof, and a magnetic recording / reproducing apparatus.

  In recent years, the application range of magnetic recording devices such as magnetic disk devices, flexible disk devices, and magnetic tape devices has been remarkably increased and their importance has increased, and the recording density of magnetic recording media used in these devices has been significantly improved. It is being planned. In particular, since the introduction of MR heads and PRML technology, the increase in surface recording density has become more intense. In recent years, GMR heads, TMR heads, etc. have been further introduced and have been increasing at a rate of about 100% per year. For these magnetic recording media, it is required to achieve higher recording density in the future. For this purpose, it is required to achieve higher coercivity, high signal-to-noise ratio (SNR), and higher resolution of the magnetic recording layer. Has been. In recent years, efforts have been made to increase the surface recording density by increasing the track density as well as improving the linear recording density.

  In the latest magnetic recording apparatus, the track density has reached 110 kTPI. However, as the track density is increased, magnetic recording information between adjacent tracks interfere with each other, and the problem that the magnetization transition region in the boundary region becomes a noise source and the SNR is easily lost. This directly leads to a decrease in Bit Error rate, which is an obstacle to improving the recording density.

  In order to increase the surface recording density, it is necessary to make the size of each recording bit on the magnetic recording medium finer and ensure as much saturation magnetization and magnetic film thickness as possible for each recording bit. However, when the recording bits are miniaturized, the minimum magnetization volume per bit becomes small, and there arises a problem that the recording data is lost due to magnetization reversal due to thermal fluctuation.

  In addition, since the distance between tracks is getting closer, magnetic recording devices are required to have extremely high precision track servo technology. At the same time, recording is performed widely, and playback is performed more than when recording to eliminate the influence of adjacent tracks as much as possible. In general, a method of narrowly executing is used. Although this method can minimize the influence between tracks, there is a problem that it is difficult to obtain a sufficient reproduction output, and it is difficult to secure a sufficient SNR.

  As one of the methods for achieving such a problem of thermal fluctuation, ensuring SNR, or ensuring sufficient output, forming irregularities along the tracks on the surface of the recording medium and physically separating the recording tracks. Attempts have been made to increase the track density. Such a technique is hereinafter referred to as a discrete track method, and a magnetic recording medium manufactured thereby is referred to as a discrete track medium.

  As an example of a discrete track medium, a magnetic recording medium is known in which a magnetic recording medium is formed on a non-magnetic substrate having a concavo-convex pattern formed on a surface, and a magnetic recording track and a servo signal pattern that are physically separated are formed. (For example, refer to Patent Document 1).

  In this magnetic recording medium, a ferromagnetic layer is formed on a surface of a substrate having a plurality of irregularities on the surface via a soft magnetic layer, and a protective film is formed on the surface. In this magnetic recording medium, a magnetic recording area magnetically separated from the surroundings is formed in the convex area.

  According to this magnetic recording medium, the occurrence of a domain wall in the soft magnetic layer can be suppressed, so that the influence of thermal fluctuation is difficult to occur, and there is no interference between adjacent signals, so that a high-density magnetic recording medium with less noise can be formed. ing.

The discrete track method includes a method in which a track is formed after a magnetic recording medium consisting of several thin films is formed, and a magnetic pattern is formed after a concave / convex pattern is formed directly on the substrate surface in advance or on a thin film layer for track formation. There is a method of forming a thin film of a recording medium (see, for example, Patent Document 2 and Patent Document 3). Among these, the former method is often called a magnetic layer processing type, and since physical processing on the surface is performed after the medium is formed, there is a drawback that the medium is easily contaminated in the manufacturing process, and the manufacturing process is very complicated. Met. On the other hand, the latter is often referred to as an embossing die, and it is difficult to contaminate during the manufacturing process, but the uneven shape formed on the substrate is inherited by the film on which the film is formed. There has been a problem that the flying posture and flying height of a recording / reproducing head for recording / reproducing are not stable.
JP 2004-164692 A JP 2004-178793 A JP 2004-178794 A

  In the embossing type manufacturing method, a concavo-convex shape is formed on a substrate, and a magnetic layer and a protective layer are formed thereon, so that it is not easy to realize a flat surface by taking over the concavo-convex shape as it is.

On the other hand, in the discrete track type magnetic recording medium by the magnetic layer processing type, a magnetic layer for recording is formed on the surface of the substrate, and then a magnetic pattern is formed, so that the pattern is formed by an imprint method used in a semiconductor or the like. A portion that should become a nonmagnetic portion later is dry etched, for example, and thereafter SiO ₂ or a carbon nonmagnetic material is embedded, the surface is flattened, and the surface is further covered with a protective film layer, and a lubricating layer is formed. It has a structure. Such a magnetic etching type discrete track medium not only has a complicated manufacturing process and causes contamination, but also cannot realize a flat surface.

  In general, in a magnetic recording medium having such a structure, the thinner the protective film layer, the shorter the distance between the head and the magnetic layer, so that the input / output of signals at the head increases and the recording density can be increased. The pit density in the track is determined by the flying height of the head running on the surface of the uneven protective film layer. Therefore, how to maintain stable head flying is an important issue for achieving high recording density. Therefore, there is a need for a concavo-convex pattern that keeps the head flying as close as possible and makes the head as close as possible to the magnetic layer and prevents mutual interference of signals with adjacent tracks.

  However, there has not yet been proposed a technique for manufacturing a discrete track medium with a low risk of contamination in the manufacturing process and a flat surface.

The present invention significantly increases the track density while maintaining the same or better recording / reproducing characteristics in a magnetic recording apparatus that is facing technical difficulties as the track density increases. It is to increase the density. In particular, in a discrete track type magnetic recording medium in which irregularities are formed after forming a magnetic layer on a substrate, the manufacturing process is greatly simplified by eliminating the magnetic layer removal step compared to the conventional magnetic layer processing type. And a useful discrete track type magnetic recording medium having excellent head flying characteristics and a low manufacturing risk.

In order to solve the above-mentioned problems, the present inventor has intensively studied to arrive at the present invention. That is, the present invention relates to the following.
(1) A discrete track type magnetic recording medium in which a physically separated magnetic recording track and a servo signal pattern are formed on at least one surface of a nonmagnetic substrate, wherein the magnetic recording track and the servo signal pattern portion are A magnetic recording medium, wherein the nonmagnetic part intended to be physically separated is a nonmagnetic alloy containing Si.
(2) The magnetic recording medium according to (1), wherein the surface roughness is in a range of 0.1 nm ≦ Ra ≦ 2.0 nm.
(3) The magnetic recording medium according to (1) or (2), wherein the magnetic recording track is a perpendicular magnetic recording track.
(4) A method of manufacturing a discrete track type magnetic recording medium in which a physically separated magnetic recording track and a servo signal pattern are formed on at least one surface of a nonmagnetic substrate, wherein the magnetic recording track and the servo signal The non-magnetic part intended to physically separate the pattern part is formed of a non-magnetic alloy containing Si. In forming the non-magnetic alloy, after forming Si on the magnetic layer, heating or A method of manufacturing a magnetic recording medium, characterized in that Si is diffused in a magnetic layer by irradiating the surface of Si with active ions.
(5) The magnetic recording medium according to any one of (1) to (3), a drive unit that drives the magnetic recording medium in a recording direction, a magnetic head including a recording unit and a reproducing unit, and a magnetic head And a recording / reproducing signal processing means for reproducing a signal input to the magnetic head and reproducing an output signal from the magnetic head. Playback device.

  According to the present invention, in a magnetic layer processed type discrete track magnetic recording medium, the head flying stability can be secured, the track separation performance is excellent, the signal interference between adjacent tracks is not affected, and the high recording A magnetic recording medium having excellent density characteristics can be provided. In addition, since the dry etching process for removing the magnetic layer of the magnetic layer processing type, which has heretofore been very complicated in manufacturing process, can be omitted, it can greatly contribute to the improvement of productivity.

  In addition, since the magnetic recording / reproducing apparatus of the present invention uses the magnetic recording medium of the present invention, it has excellent head flying characteristics, excellent track separation performance, and is not affected by signal interference between adjacent tracks. Thus, a magnetic recording / reproducing apparatus excellent in high recording density characteristics can be obtained.

  First, the sectional structure of the discrete magnetic recording medium of the present invention will be described.

  FIG. 1 shows a cross-sectional structure of a discrete magnetic recording medium of the present invention. In the magnetic recording medium 30 of the present invention, a soft magnetic layer and an intermediate layer 2, a magnetic layer 3 with a magnetic pattern formed thereon, a non-magnetized layer 4 and a protective film layer 5 are formed on the surface of a non-magnetic substrate 1. Furthermore, it has a structure in which a lubricating film (not shown) is formed on the outermost surface.

  In order to increase the recording density, the magnetic part width W of the magnetic layer 3 having a magnetic pattern is preferably 100 nm or less, and the nonmagnetic part width L is preferably 200 nm or less. Accordingly, the track pitch P (= W + L) is in the range of 300 nm or less, and is made as narrow as possible in order to increase the recording density.

  Nonmagnetic substrates used in the present invention include Al alloy substrates such as Al-Mg alloys mainly composed of Al, ordinary soda glass, aluminosilicate glass, crystallized glass, silicon, titanium, ceramics, Any nonmagnetic substrate such as a substrate made of various resins can be used. Among them, it is preferable to use a glass substrate such as an Al alloy substrate or crystallized glass, or a silicon substrate. The average surface roughness (Ra) of these substrates is preferably 1 nm or less, more preferably 0.5 nm or less, and particularly preferably 0.1 nm or less.

  The magnetic layer formed on the surface of the nonmagnetic substrate as described above may be an in-plane magnetic recording layer or a perpendicular magnetic recording layer, but a perpendicular magnetic recording layer is preferable in order to realize a higher recording density. These magnetic recording layers are preferably formed from an alloy mainly containing Co as a main component.

  For example, as a magnetic recording layer for an in-plane magnetic recording medium, a laminated structure composed of a nonmagnetic CrMo underlayer and a ferromagnetic CoCrPtTa magnetic layer can be used.

Examples of magnetic recording layers for perpendicular magnetic recording media include soft magnetic FeCo alloys (FeCoB, FeCoSiB, FeCoZr, FeCoZrB, FeCoZrBCu, etc.), FeTa alloys (FeTaN, FeTaC, etc.), Co alloys (CoTaZr, CoZrNB, CoB, etc.). A backing layer made of, etc., an orientation control film such as Pt, Pd, NiCr, NiFeCr, an intermediate film such as Ru, if necessary, and a magnetic layer made of 60Co-15Cr-15Pt alloy or 70Co-5Cr-15Pt-10SiO ₂ alloy Can be used.

  The thickness of the magnetic recording layer is 3 nm to 20 nm, preferably 5 nm to 15 nm. The magnetic recording layer may be formed so as to obtain sufficient head input / output according to the type of magnetic alloy used and the laminated structure. The film thickness of the magnetic layer requires a certain thickness of the magnetic layer in order to obtain a certain level of output during playback. On the other hand, parameters indicating recording / playback characteristics usually deteriorate as the output increases. Therefore, it is necessary to set an optimum film thickness.

  Usually, the magnetic recording layer is formed as a thin film by sputtering.

A protective film layer 5 is formed on the surface of the magnetic recording layer. As the protective film layer, a carbonaceous layer such as carbon (C), hydrogenated carbon (HxC), nitrogenated carbon (CN), alumocarbon, silicon carbide (SiC), SiO ₂ , Zr ₂ O ₃ , TiN, etc. Ordinarily used protective film layer materials can be used. Further, the protective film layer may be composed of two or more layers.

  The film thickness of the protective film layer 3 needs to be less than 10 nm. This is because if the thickness of the protective film layer exceeds 10 nm, the distance between the head and the magnetic layer increases, and sufficient input / output signal strength cannot be obtained. Usually, the protective film layer is formed by sputtering or CVD.

  A lubricating layer is preferably formed on the protective film layer. Examples of the lubricant used for the lubricating layer include a fluorine-based lubricant, a hydrocarbon-based lubricant, and a mixture thereof, and the lubricating layer is usually formed with a thickness of 1 to 4 nm.

  Next, the method for producing the discrete magnetic recording medium of the present invention will be specifically described.

  In the manufacturing process of the magnetic recording medium, the substrate is usually first washed and dried, and in the present invention, from the viewpoint of ensuring the adhesion of each layer, the substrate is washed and dried before the formation of the magnetic film layer. It is desirable. Also, the substrate size is not particularly limited.

In the present invention, FeCoB as a soft magnetic layer, Ru as an intermediate layer, 70Co-5Cr-15Pt-10SiO ₂ alloy as a magnetic layer, and Carbon as a protective layer are formed on the surface of the substrate. Then, after applying resist and forming a pattern, the resist corresponding to the concave portion of the pattern and Carbon are removed by reactive ion etching, and then Si is formed on the magnetic layer and then heated or irradiated with inert ions. After diffusing to the magnetic layer underneath, forming a magnetic pattern designed to match the distance between tracks by diffusing and alloying Si into the magnetic layer, then removing the resist and re-forming the protective layer Then, a magnetic recording medium is manufactured by applying a lubricant.
A sputtering method was used for forming the Si film. In the ion beam irradiation, an inert atom such as Ar or Kr may be used. In the present invention, Ar is used.

  In addition, in the pattern formation after the resist application, a track-shaped unevenness is formed on the surface of the protective film by bringing the stamper into close contact with the protective film formed subsequent to the substrate or the magnetic layer and pressing at high pressure. . Or the uneven | corrugated pattern formed using thermosetting resin, UV curable resin, etc. may be sufficient.

  As the stamper used in the above-mentioned process, for example, a metal plate formed with a fine track pattern using a method such as electron beam drawing can be used, and the material is required to have hardness and durability that can withstand the process. . For example, Ni can be used, but any material can be used as long as it meets the above-mentioned purpose. A servo signal pattern such as a burst pattern, a gray code pattern, and a preamble pattern is formed on the stamper in addition to a track for recording normal data.

  When removing the resist, the resist on the surface and part of the protective layer are removed using a technique such as dry etching, reactive ion etching, or ion milling. As a result of these treatments, the magnetic layer on which the magnetic pattern is formed and a part of the protective layer remain. By selecting the conditions, it is possible to completely remove the protective layer and leave only the magnetic layer on which the pattern is formed.

  Of the layers of the magnetic recording medium, the layers other than the protective film layer 3 can be formed using an RF sputtering method or a DC sputtering method that is generally used as a film forming method.

  On the other hand, the method of forming the protective film layer is not particularly limited, although a method of forming a thin film of Diamond Like Carbon using P-CVD or the like is generally performed.

Next, the configuration of the magnetic recording / reproducing apparatus of the present invention is shown in FIG. The magnetic recording / reproducing apparatus of the present invention includes the magnetic recording medium 30 of the present invention described above, the medium driving unit 11 that drives the magnetic recording medium 30 in the recording direction, the magnetic head 27 that includes the recording unit and the reproducing unit, A head drive unit 28 that moves relative to the recording medium 30 and a recording / reproduction signal system 29 that combines recording / reproduction signal processing means for performing signal input to the magnetic head 27 and output signal reproduction from the magnetic head 27. It is equipped. By combining these, it is possible to configure a magnetic recording apparatus with a high recording density. By processing the recording track of the magnetic recording medium physically discontinuously, conventionally, the reproducing head width was made narrower than the recording head width in order to eliminate the influence of the magnetization transition region at the track edge portion. Can be operated with both of them approximately the same width. As a result, sufficient reproduction output and high SNR can be obtained.
Furthermore, by configuring the reproducing section of the magnetic head as a GMR head or TMR head, a sufficient signal intensity can be obtained even at a high recording density, and a magnetic recording apparatus having a high recording density can be realized. . Also, when the flying height of this magnetic head is lowered to 0.005 μm to 0.020 μm, which is lower than the conventional height, the output is improved and a high device SNR is obtained, and a large capacity and high reliability magnetic recording device is provided. can do. Further, the recording density can be further improved by combining the signal processing circuit based on the maximum likelihood decoding method. For example, the track density is 100 ktrack / inch or more, the linear recording density is 1000 kbit / inch or more, and the recording density is 100 Gbit or more per square inch A sufficient SNR can also be obtained when recording / reproducing.

(Comparative Example 1)
The vacuum chamber in which the glass substrate for HD was set was evacuated to 1.0 × 10 ⁻⁵ Pa or less in advance. The glass substrate used here is composed of Li ₂ Si ₂ O ₅ , Al ₂ O ₃ —K ₂ O, Al ₂ O ₃ —K ₂ O, MgO—P ₂ O ₅ , and Sb ₂ O ₃ —ZnO. It is made of crystallized glass and has an outer diameter of 65 mm, an inner diameter of 20 mm, and an average surface roughness (Ra) of 2 angstroms.

  A SiO2 film having a thickness of 200 nm was formed on the glass substrate by using a normal RF sputtering method as a pre-embossed layer.

  Next, imprinting was performed using a Ni stamper prepared in advance. A stamper having a Track pitch of 100 nm was prepared. The depth of each groove was adjusted to 20 nm. Imprinting was performed using each stamper.

Next, the SiO ₂ layer was etched using ion beam etching. The thin part of the SiO ₂ layer was etched deeply to the substrate to form a concavo-convex pattern according to the concavo-convex pattern by the stamper on the substrate surface.

A DC sputtering method is used on the surface of these substrates, FeCoB as a soft magnetic layer, Ru as an intermediate layer, 70Co-5Cr-15Pt-10SiO ₂ alloy as a magnetic layer, and a C (carbon) protective film layer using a P-CVD method. Then, the thin films were laminated in the order of the fluorine-based lubricating film.

The thicknesses of the respective layers were 600 は for the FeCoB soft magnetic layer, 100 は for the Ru intermediate layer, and 150 Å C (carbon) protective film layer for the magnetic layer on average of 4 nm. This sample was produced as Comparative Example 1 as an example of an embossing mold.
(Comparative Example 2)
The vacuum chamber in which the glass substrate for HD was set was evacuated to 1.0 × 10 ⁻⁵ Pa or less in advance. The glass substrate used here is composed of Li ₂ Si ₂ O ₅ , Al ₂ O ₃ —K ₂ O, Al ₂ O ₃ —K ₂ O, MgO—P ₂ O ₅ , and Sb ₂ O ₃ —ZnO. It is made of crystallized glass and has an outer diameter of 65 mm, an inner diameter of 20 mm, and an average surface roughness (Ra) of 2 angstroms.

Using a DC sputtering method on the glass substrate, FeCoB as a soft magnetic layer, Ru as an intermediate layer, 70Co-5Cr-15Pt-10SiO ₂ alloy as a magnetic layer, a C (carbon) protective film layer using a P-CVD method, Thin films were laminated in the order of the fluorine-based lubricating film. The thickness of each layer was 600Å for the FeCoB soft magnetic layer, 100Å for the Ru intermediate layer, 150Å for the magnetic layer, and an average of 4 nm for the C (carbon) protective film layer. Thereafter, a magnetic pattern was formed by magnetic layer processing. That is, after applying a thermosetting resin resist to form irregularities corresponding to the pattern, the magnetic layer in the concave portion is removed by ion milling in a vacuum apparatus, and the remaining convex resist is peeled and removed to the magnetic layer portion. Carbon was deposited for the purpose of embedding. Thereafter, Carbon was formed into a 4 nm film by the P-CVD method, and a lubricant was applied. Surface smoothing was performed using ion beam etching. A sample was put in a vacuum chamber that was previously evacuated to 1 × 10 ⁻⁴ Pa, and Ar gas was introduced so that the partial pressure was 5 Pa. An RF voltage of 300 W was applied to the sample, and the sample surface was etched. This sample was produced as Comparative Example 2 as an example of a magnetic layer processing mold.

In the embedding process, a nonmagnetic material is used as the embedding material. Carbon was used in the preparation of this sample. A filming method was used for film formation.
(Examples 1-5)
As in Comparative Example 2, the vacuum chamber in which the HD glass substrate was set was evacuated to 1.0 × 10 ⁻⁵ Pa or less in advance. The glass substrate used here is Li ₂ Si ₂ O ₅ , Al ₂ O ₃ —K ₂ O.
, Al ₂ O ₃ —K ₂ O, MgO—P ₂ O ₅ , Sb ₂ O ₃ —ZnO as a constituent, crystallized glass is used as a material, outer diameter 65 mm, inner diameter 20 mm, average surface roughness (Ra) is 2 angstroms.

A DC sputtering method is used for the glass substrate, FeCoB as a soft magnetic layer, Ru as an intermediate layer, 70Co-5Cr-15Pt-10SiO ₂ alloy as a magnetic layer, a C (carbon) protective film layer using a P-CVD method, Thin films were laminated in the order of the fluorine-based lubricating film. The thickness of each layer was 600Å for the FeCoB soft magnetic layer, 100Å for the Ru intermediate layer, 150Å for the magnetic layer, and an average of 4 nm for the C (carbon) protective film layer. Thereafter, a magnetic pattern was formed. That is, after applying a thermosetting resin resist to form irregularities corresponding to the pattern, only the concave resist is removed by a reactive etching method, Si is formed by a sputtering method, and then heated to form Si on the magnetic layer. After forming a magnetic pattern designed to match the distance between tracks, the resist and the protective film were removed, and a protective layer was formed again to 4 nm, and a lubricant was applied to manufacture a magnetic recording medium. . These samples were designated as Examples 1-5. The film thickness of Si, heating conditions, etc. are shown in Table 1.
(Examples 6 to 10)
As in Comparative Example 2, the vacuum chamber in which the HD glass substrate was set was evacuated to 1.0 × 10 ⁻⁵ Pa or less in advance. The glass substrate used here is Li ₂ Si ₂ O ₅ , Al ₂ O ₃ —K ₂ O.
, Al ₂ O ₃ —K ₂ O, MgO—P ₂ O ₅ , Sb ₂ O ₃ —ZnO as a constituent, crystallized glass is used as a material, outer diameter 65 mm, inner diameter 20 mm, average surface roughness (Ra) is 2 angstroms.

Using a DC sputtering method on the glass substrate, FeCoB as a soft magnetic layer, Ru as an intermediate layer, 70Co-5Cr-15Pt-10SiO ₂ alloy as a magnetic layer, a C (carbon) protective film layer using a P-CVD method, Thin films were laminated in the order of the fluorine-based lubricating film. The thickness of each layer was 600Å for the FeCoB soft magnetic layer, 100Å for the Ru intermediate layer, 150Å for the magnetic layer, and an average of 4 nm for the C (carbon) protective film layer. Thereafter, a magnetic pattern was formed. That is, after applying a thermosetting resin resist to form irregularities corresponding to the pattern, only the resist in the concave portions is removed by a reactive etching method, and Si is formed by a sputtering method. After the Si surface is irradiated to diffuse Si into the magnetic layer and a magnetic pattern designed according to the distance between tracks is formed, the resist and the protective film are removed and the protective layer is re-formed to 4 nm, and then the lubricant Was applied to produce a magnetic recording medium. These samples were referred to as Examples 6 to 10. The film thickness of Si, heating conditions, etc. are shown in Table 1.
(Comparative Examples 3 and 4)
Comparative Examples 3 and 4 were produced by the same production method as in Examples 1 to 10, except that heating was not performed after the Si film was formed and Ar irradiation with an ion beam was not performed. At this time, the Si film thickness was set to 10,500 nm , respectively.

Examples 1 to 10 and Comparative Examples 1, 2, 3, and 4 were evaluated for electromagnetic conversion characteristics using a spin stand. At this time, as an evaluation head, a perpendicular recording head was used for recording and a TuMR head was used for reading. The SNR value and 3T-squash (triple track squash: signal intensity of the center track when writing on both side adjacent tracks) when a 750 kFCI signal was recorded were measured. In Examples 1 to 10, it was found that RW characteristics such as SNR and 3T-squash were significantly improved as compared with Comparative Examples 1 and 2. This is thought to be because the head flying characteristics were stable and RW could be achieved at a predetermined flying height. In addition, by confirming the RW characteristics such as SNR and 3T-squash, the samples of Examples 1 to 10 were confirmed to be separated from each other by the nonmagnetic portion between the tracks. It was also confirmed that the magnetic pattern of the corresponding magnetic part and nonmagnetic part was formed in the magnetic layer part of the sample of the example by diffusion of Si. On the other hand, in Comparative Examples 3 and 4, both the SNR and 3T-squash are significantly worse than the samples of Examples 1 to 10, and it can be seen that no magnetic pattern is formed because Si is not diffused.

  After completion of the measurement of the electromagnetic conversion characteristics, the surface roughness of Examples 1 to 10 and Comparative Examples 1, 2, 3, and 4 was measured using AFM. Using an AFM manufactured by Digital Instrument, the roughness (Ra) of the non-magnetic substrate for perpendicular recording media prepared in the present example and the comparative example is evaluated in a 10 μm visual field. Other settings were made at a resolution of 256 × 256 tapping mode and a sweep speed of 1 μm / sec. The results are shown in Table 1. In Examples 1 to 10, the surface roughness was significantly lower than those in Comparative Examples 1 and 2, and it was considered that the head flying was stabilized.

  The glide avalanche characteristics of Examples 1 to 10 and Comparative Examples 1, 2, 3, and 4 were evaluated. For the evaluation, a 50% slider head manufactured by Glide Light was used, and measurement was performed with a DS4100 device manufactured by Sony Tektro Corporation. The measurement results are shown in Table 1. It can be seen that Examples 1 to 10 have a lower glide avalanche than Comparative Examples 1 and 2, and good head flying characteristics.

  From the comparison between Examples 1 to 10 and Comparative Examples 1, 2, 3, and 4, according to the present invention, an Si-containing alloy can be easily formed into a non-magnetic portion for the purpose of physical separation of patterns, thereby providing a discrete medium. It was revealed that the surface roughness was sufficiently low and the flying of the head could be stabilized. As apparent from the comparison between this example and the comparative example, manufacturing the surface roughness as low as possible is an important factor for stabilizing the flying of the head. In the present invention, the surface roughness is Ra ≦ 2 nm. More preferably, it is desirable that Ra ≦ 1.5 nm. In addition, it is clear that the present invention is an effective means for separating patterned nonmagnetic and magnetic layers, and is also effective for the manufacture of patterned media aiming at higher recording density than the discrete method. It has also been proven.

It is a figure which shows the cross-section of the magnetic recording medium of this invention. It is a figure explaining the structure of the magnetic recording / reproducing apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Nonmagnetic board | substrate 2 Soft magnetic layer and intermediate | middle layer 3 Magnetic recording layer 4 Demagnetization layer 5 Protective layer 26 Medium drive part 27 Magnetic head 28 Head drive part 29 Recording / reproducing signal system 30 Magnetic recording medium

Claims (4)

A method of manufacturing a discrete track type magnetic recording medium in which a physically separated magnetic recording track and a servo signal pattern are formed on at least one surface of a nonmagnetic substrate, wherein the magnetic recording track and the servo signal pattern portion are A non-magnetic part intended to be physically separated is formed of a non-magnetic alloy containing Si. In forming the non-magnetic alloy, after depositing Si on the magnetic layer , inert ions are formed on the Si surface. A method of manufacturing a magnetic recording medium, characterized by diffusing Si in a magnetic layer by irradiation . 2. The method of manufacturing a magnetic recording medium according to claim 1, wherein the surface roughness is in a range of 0.1 nm ≦ Ra ≦ 2.0 nm. 3. The method of manufacturing a magnetic recording medium according to claim 1, wherein the magnetic recording track is a perpendicular magnetic recording track. A magnetic recording medium manufactured by the method for manufacturing a magnetic recording medium according to any one of claims 1 to 3, a drive unit that drives the magnetic recording medium in a recording direction, and a magnetic head that includes a recording unit and a reproducing unit And a means for moving the magnetic head relative to the magnetic recording medium and a recording / reproduction signal processing means for performing signal input to the magnetic head and output signal reproduction from the magnetic head. A magnetic recording / reproducing apparatus.

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