JP2010140556A - Magnetic recording medium and manufacturing method therefor, and magnetic recording and reproducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic recording medium of which the recording layer has excellent corrosion resistance in an ECC medium. <P>SOLUTION: The magnetic recording medium includes: a substrate 10; a soft magnetic layer 20 formed on the substrate 10; a first magnetic layer 30 formed on the soft magnetic layer 20 and including a compound M<SB>1</SB>X; a nonmagnetic layer 40 formed so as to cover a portion of the surface of the first magnetic layer 30; a second magnetic layer 50 formed on the nonmagnetic layer 40 and including a compound M<SB>2</SB>X; and a protective layer 60 formed on the second magnetic layer 50, wherein M<SB>1</SB>and M<SB>2</SB>are elements selected from Si, Ti, Cr, Ta, W, Hf, Nb, and Mo, X is an element selected from O or N, and when mass numbers of M<SB>1</SB>and M<SB>2</SB>are represented by m<SB>1</SB>and m<SB>2</SB>, mass numbers of elements selected for M<SB>1</SB>and M<SB>2</SB>satisfy inequality m<SB>1</SB><m<SB>2</SB>. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a magnetic recording / reproducing apparatus capable of high-density recording, a magnetic recording medium, and a manufacturing method thereof.

  In a magnetic recording / reproducing apparatus such as an HDD (Hard Disc Drive), two layers having different magnetic anisotropy energy (Ku) are stacked on one of the magnetic recording media as a means for improving the recording density. In addition, there is an ECC (Exchange Coupled Composite) medium (see, for example, Patent Document 1 and Patent Document 2). In order to increase the recording density, it is effective to make the magnetic particles finer and reduce the magnetic interaction. However, since the thermal fluctuation increases when the particles are made finer, it is necessary to increase the magnetic anisotropy energy Ku value (hereinafter referred to as Ku value).

  However, when the Ku value is increased, the magnetic field intensity required for recording increases, and recording with a recording / reproducing head becomes difficult. The ECC medium can reduce the problem of thermal fluctuation caused by the refinement of particles in a layer having a large Ku value, and can reduce the reversal magnetic field in a layer having a small Ku value and can be written by a recording / reproducing head.

  On the other hand, as another means for improving the recording density, there is a magnetic recording medium called a discrete track type pattern medium (hereinafter referred to as a DTR medium) that physically separates recording tracks. Since the DTR medium can reduce the side erase phenomenon during recording and the side lead phenomenon in which information of adjacent tracks is mixed during reproduction, the density in the track direction can be greatly increased. A recording medium can be provided. Furthermore, since the DTR medium is also produced on the disk as servo information collectively as a pattern, it is not necessary to write servo signals with a magnetic head over a long time.

Therefore, it is possible to further increase the recording density by producing a DTR medium using an ECC medium.
JP 2008-65879 A JP 2008-97685 A

  However, when an oxide having a low density is used as the additive, there is a problem that the magnetic body is easily corroded. Further, in order to obtain the flying characteristics of the recording / reproducing head, the DTR medium needs to demagnetize the magnetic component by RIE (Reactive Ion Etching) method without milling part of the recording layer, but the density is low. Recording layers using oxides are susceptible to side damage when demagnetizing the magnetic component.

  On the other hand, when a high-density oxide is used as the additive, the magnetic material is hardly corroded, but the magnetic component is not easily demagnetized during the processing of the DTR medium, which is not suitable for mass production. Further, there is a problem that even if the magnetic component is sufficiently demagnetized, side damage occurs as in the case of using an oxide having a low density due to demagnetization for a long time.

  Also, during processing of the DTR medium, distortion occurs between the two recording layers having different Ku values due to the thermal energy generated in the etching process, the adhesion of the protective layer above the recording layer deteriorates, and the flying characteristics of the recording / reproducing head There was a problem of getting worse.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic recording medium, a manufacturing method thereof, and a magnetic recording / reproducing apparatus, which are excellent in corrosion resistance of a recording layer, hardly cause side damage, and have good flying characteristics in a DTR medium using an ECC medium. It is to provide.

In order to achieve the above object, a magnetic recording medium according to the present invention includes a substrate, a soft magnetic layer formed on the substrate, a first magnetic layer including a compound M ₁ X formed on the soft magnetic layer, Formed on the second magnetic layer, a nonmagnetic layer formed on the first magnetic layer so as to cover a part of the surface, a second magnetic layer containing the compound M ₂ X formed on the nonmagnetic layer, and the second magnetic layer And M ₁ and M ₂ are elements selected from Si, Ti, Cr, Ta, W, Hf, Nb, and Mo, and X is an element selected from O or N. The mass numbers of the elements M ₁ and M ₂ are in a relationship of M ₁ <M ₂ .

  The DTR medium according to the present invention can provide a magnetic recording medium in which the recording layer has excellent corrosion resistance.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
Hereinafter, the same reference numerals in the drawings denote the same elements, and redundant description is omitted.

  FIG. 1 shows a cross-sectional view of a DTR medium using the ECC medium according to the first embodiment. The DTR medium in the present embodiment is laminated on the substrate 10 in order from the lower layer, the soft magnetic layer 20, the recording layer 70 (ECC medium), and the protective layer 60. The recording layer 70 includes at least a first magnetic layer 30, an exchange coupling control layer 40, and a second magnetic layer 50.

  As the substrate 10, for example, a glass substrate, an Al-based alloy substrate, ceramic, carbon, a Si single crystal substrate having an oxidized surface, and those obtained by plating such a substrate with NiP or the like can be used. As the glass substrate, there are amorphous glass and crystallized glass, and general-purpose soda lime glass and aluminosilicate glass can be used as the amorphous glass. Further, as the crystallized glass, lithium-based crystallized glass can be used. As the ceramic substrate, a sintered body mainly composed of general-purpose aluminum oxide, aluminum nitride, silicon nitride, or the like, or a fiber reinforced material thereof can be used. In addition, it is possible to use a metal substrate or a non-metal substrate having a NiP layer formed on the surface thereof by plating or sputtering. Further, only the sputtering method has been taken up as a method for forming a thin film on the substrate 10, but a similar effect can be obtained by a vacuum deposition method, an electrolytic plating method, or the like.

  The soft magnetic layer 20 has a part of the function of the magnetic head for circulating a recording magnetic field from a magnetic head for magnetizing the recording layer 70, for example, a single magnetic pole head, to the magnetic head side in the horizontal direction. Thus, a steep and sufficient perpendicular magnetic field is applied to the magnetic recording layer 70 to increase the recording / reproducing efficiency.

  A material containing Fe, Ni, and Co can be used for the soft magnetic layer 20. Examples of such materials include FeCo alloys such as FeCo and FeCoV, FeNi alloys such as FeNi, FeNiMo, FeNiCr, and FeNiSi, FeAl alloys and FeSi alloys such as FeAl, FeAlSi, FeAlSiCr, FeAlSiTiRu, and FeAlO. Examples thereof include FeTa alloys such as FeTa, FeTaC, and FeTaN, and FeZr alloys such as FeZrN. Further, a material having a fine crystal structure such as FeAlO, FeMgO, FeTaN, FeZrN or the like containing 60 at% or more of Fe or a granular structure in which fine crystal particles are dispersed in a matrix can be used.

  As another material of the soft magnetic layer 20, a Co alloy containing Co and at least one of Zr, Hf, Nb, Ta, Ti, and Y can be used. Co is preferably contained at 80 at% or more. When such Co alloy is formed by sputtering, an amorphous layer is likely to be formed, and amorphous soft magnetic materials do not have magnetocrystalline anisotropy, crystal defects, and grain boundaries, and thus have excellent soft magnetism. Show. Further, the use of this amorphous soft magnetic material can reduce the noise of the medium. Examples of the optimum amorphous soft magnetic material include CoZr, CoZrNb, and CoZrTa-based alloys.

  Further, an underlayer (not shown) can be provided under the soft magnetic layer 20 in order to improve the crystallinity of the soft magnetic layer 20 or the adhesion to the substrate 10. As the underlayer material, Ti, Ta, W, Cr, Pt, alloys containing these, oxides or nitrides thereof can be used. In order to prevent spike noise, the soft magnetic layer 20 may be divided into a plurality of layers and antiferromagnetically coupled by inserting Ru of 0.5 to 1.5 nm. At that time, in order to control the exchange coupling force, a magnetic (for example, Co) or non-magnetic film (for example, Pt) may be laminated before and after the Ru layer.

  An intermediate layer (not shown) made of a nonmagnetic material can be provided between the soft magnetic layer 20 and the recording layer 70. There are two roles of the intermediate layer: blocking the exchange coupling interaction between the soft magnetic layer 20 and the recording layer 70 and controlling the crystallinity of the recording layer 70. As the intermediate layer material, Ru, Pt, Pd, W, Ti, Ta, Cr, Si, alloys containing these, oxides or nitrides thereof can be used.

  The recording layer 70 functions to perform perpendicular magnetic recording. At least the first magnetic layer 30, the exchange coupling control layer 40, and the second magnetic layer 50 are included. The first magnetic layer 30 having a large Ku value and the second magnetic layer 50 having a small Ku value are magnetically weakly coupled via the exchange coupling control layer 40, and the first magnetic layer 30 and the second magnetic layer 50 are coupled to each other. The magnetic layer 50 is controlled by the exchange coupling force by the exchange coupling control layer 40.

  In addition, in the recording layer 70, it is preferable to add a material that becomes a nonmagnetic grain boundary component to the recording layer 70 in order to suppress the interaction between the particles.

  Further, in the first magnetic layer 30 and the second magnetic layer 50, it is preferable that magnetic particles (crystal grains having magnetism) are dispersed in the layers.

The first magnetic layer 30 and the second magnetic layer 50 are made of a nonmagnetic material containing Co or a main component and containing an oxide or a nitride. The oxide and nitride are preferably MX (M is an element such as Si, Ti, Cr, Ta, W, Hf, Nb, and Mo, and X is an element made of O or N). _{Specifically, SiO 2, TiO 2, Cr} 2 O 3, Ta 2 O 5, WO 3, HfO 2, NbO 2, MoO 2, Si 3 N 4, TiN, Cr 2 N, TaN, WN 2, HfN , NbN, Mo ₂ N and the like. In particular, it is preferable that the first magnetic layer 30 is SiO ₂ and the second magnetic layer 50 is TiO ₂ . _This, SiO 2, TiO ₂ in order better diffusion less crystalline coordination tropism for magnetic, because high-quality crystal is obtained.

When the mass number of these elements M is expressed as m, the relationship is m ₁ <m ₂ (the subscript “1” represents the first magnetic layer 30 and the subscript “2” represents the first 2 represents the magnetic layer 50 of 2).

  By using this relationship, when the first magnetic layer 30 and the second magnetic layer 50 are altered by the RIE method, the magnetic component in the first magnetic layer 30 is likely to be demagnetized, and the second magnetic layer In 50, it becomes difficult for the magnetic component to become non-magnetic. That is, side damage to the second magnetic layer 50 can be suppressed.

  Also, when the second magnetic layer 50 is processed by ion milling, the second magnetic layer 50 has a higher density than the first magnetic layer 30 and thus is less likely to be corroded and maintains flatness. can do. Therefore, the adhesion with the protective layer 60 is improved, and the flying characteristics of the recording / reproducing head can be improved.

  Details of the RIE process and the ion milling process will be described later.

  The magnetic particles preferably have a columnar structure that vertically penetrates the first magnetic layer 30 and the second magnetic layer 50. By forming such a structure, the orientation and crystallinity of the magnetic particles of the first magnetic layer 30 and the second magnetic layer 50 are made favorable, and as a result, a signal / noise ratio suitable for high-density recording ( S / N ratio) can be obtained.

  In order to obtain such a structure, the amount of oxide to be contained is important. The content of the oxide is preferably 5 mol% or more and 20 mol% or less with respect to the total amount of Co, Cr, and Pt. More preferably, it is 8 mol% or more and 13 mol% or less. The reason why the above-mentioned range is preferable as the oxide content in the first magnetic layer 30 and the second magnetic layer 50 is that when the layer is formed, the oxide is precipitated around the magnetic particles and the magnetic particles are isolated. This is because it can be miniaturized. When the oxide content exceeds the above range, the oxide remains in the magnetic particles, and the orientation and crystallinity of the magnetic particles are impaired. This is not preferable because a columnar structure in which magnetic particles penetrate the first magnetic layer 30 and the second magnetic layer 50 vertically is not formed.

  In addition, when the oxide content is less than the above range, separation and refinement of the magnetic particles are insufficient, resulting in an increase in noise during recording and reproduction, and an S / N ratio suitable for high density recording is obtained. It is not preferable because it is not possible. The Cr content in the first magnetic layer 30 and the second magnetic layer 50 is preferably 5 at% to 20 at%. More preferably, it is 10 at% or more and 18 at% or less. The Cr content is in the above range because the uniaxial crystal magnetic anisotropy constant of the magnetic particles is not lowered too much, and high magnetization is maintained. As a result, recording / reproduction characteristics suitable for high-density recording and sufficient thermal fluctuation are achieved. This is because it is preferable because the characteristics are obtained. When the Cr content exceeds the above range, the Ku value of the magnetic particles becomes small and the thermal fluctuation characteristics deteriorate.

  In addition, since the crystallinity and orientation of the magnetic particles are deteriorated, the recording / reproducing characteristics are deteriorated as a result. The Pt content in the first magnetic layer 30 and the second magnetic layer 50 is preferably 10 at% to 25 at%. The reason why the Pt content is in the above range is that the Ku value necessary for the perpendicular magnetic layer is obtained and the crystallinity and orientation of the magnetic particles are good, and as a result, thermal fluctuation characteristics suitable for high-density recording, recording / reproduction This is because characteristics are obtained. In general, magnetic particles are in the hcp (hexagonal close-packed structure) phase, but when the Pt content exceeds the above range, an fcc (face-centered cubic structure) phase is formed in the magnetic particles and the crystallinity and orientation are impaired. This is not preferable because it may be

  Further, when the Pt content is less than the above range, it is not preferable because a Ku value for obtaining thermal fluctuation characteristics suitable for high density recording cannot be obtained. The first magnetic layer 30 and the second magnetic layer 50 are selected from B, Ta, Mo, Cu, Nd, W, Nb, Sm, Tb, Ru, and Re in addition to Co, Cr, Pt, and oxide. One or more elements can be included. By including the above elements, it is possible to promote miniaturization of magnetic particles or improve crystallinity and orientation, and to obtain recording / reproducing characteristics and thermal fluctuation characteristics suitable for higher density recording. The total content of the above elements is preferably 8 at% or less. If it exceeds 8 at%, phases other than the hcp phase are formed in the magnetic particles, so that the crystallinity and orientation of the magnetic particles are disturbed, resulting in recording / reproduction characteristics and thermal fluctuation characteristics suitable for high-density recording. Since it is not possible, it is not preferable.

  In addition to the above, the first magnetic layer 30 and the second magnetic layer 50 include a CoPt alloy, a CoCr alloy, a CoPtCr alloy, CoPtO, CoPtCrO, CoPtSi, CoPtCrSi, and Pt, Pd, Rh, and A multilayer structure of an alloy mainly composed of at least one selected from the group consisting of Ru and Co and CoCr / PtCr, CoB / PdB, CoO / RhO, etc., to which Cr, B, and O are added are used. be able to. The thickness of the first magnetic layer 30 is preferably 10 nm or less, more preferably 0.5 nm to 5 nm, and the thickness of the second magnetic layer 50 is preferably 20 nm or less, more preferably 5 to 15 nm. is there. Within this range, the magnetic recording / reproducing apparatus suitable for higher recording density can be operated. If the thickness of the first magnetic layer 30 exceeds 10 nm, the magnetization reversal of the entire recording layer cannot be performed effectively. If the thickness of the second magnetic layer 50 is less than 5 nm, the reproduction output tends to be too low and the noise component tends to be higher, and the thicknesses of the first magnetic layer 30 and the second magnetic layer 50 are smaller. If it exceeds 20 nm, the reproduction output tends to be too high and the waveform tends to be distorted.

  The exchange coupling control layer 40 is formed of a nonmagnetic metal material such as Pt, Pd, Ru, Re, Rh, Ir, Au, Ag, Cu, Si, Cr, Mn, and Al and an oxide thereof. Preferably, the exchange coupling force is controlled by its thickness.

The protective layer 60 is provided for the purpose of preventing corrosion of the perpendicular magnetic recording layer and preventing damage to the medium surface when the magnetic head comes into contact with the medium. The material is preferably a protective layer formed of an insulating material containing, for example, C (carbon), SiO ₂ , and ZrO ₂ . The thickness of the protective layer 60 is preferably 1 to 10 nm. Thereby, the distance between the head and the medium can be reduced, which is suitable for high-density recording. Carbon may be classified into sp ² -bonded carbon (graphite) and sp ³ -bonded carbon (diamond). Durability and corrosion resistance are superior to sp ³ -bonded carbon, but since it is crystalline, surface smoothness is inferior to graphite. Usually, the carbon film is formed by sputtering using a graphite target. In this method, amorphous carbon in which sp ² bonded carbon and sp ³ bonded carbon are mixed is formed. Those having a large proportion of sp ³ bonded carbon are called diamond-like carbon (DLC (Diamond Like carbon)). DLC is excellent in durability and corrosion resistance, and since it is amorphous, it also has excellent surface smoothness. Therefore, DLC is used as a surface protective layer for magnetic recording media. In addition, in the DLC film formation by the CVD method, the source gas is excited and decomposed in plasma, and DLC is generated by a chemical reaction. Therefore, by combining conditions, a DLC richer in sp ³ bond carbon is formed. Can do.

  Next, a method for manufacturing a DTR medium according to the first embodiment will be described in order with reference to FIGS.

  As shown in FIG. 2, a soft magnetic layer 20, a recording layer 70, and a protective layer 60 are formed on a substrate 10 by a CVD (Chemical Vapor Deposition) method. The film forming method is not limited to CVD, and a sputtering method, a vacuum evaporation method, or the like may be used.

Next, as shown in FIG. 3, a resist 80 is applied to the surface of the protective layer 60 of FIG. 2 by spin coating. The resist 80 is used as a mask when the recording layer 70 is processed. The coating method is not limited to the spin coating method, and an ink jet method or a dip method may be used. Although SOG (Spin On Glass) is used for the resist 80, a photo-curable resist may be used. When SOG is applied by spin coating, it is preferable to adjust the SiO ₂ concentration at 5000 rpm so that the film thickness is about 80 nm.

  Next, as shown in FIG. 4, in order to process the resist 80 applied to the medium surface, the resist 80 is processed using an imprint method. In order to perform processing by the imprint method, for example, a stamper (not shown) in which a recording track and a servo information pattern are embedded is pressed at about 100 MPa, and the pattern is transferred to the resist 80.

Next, as shown in FIG. 5, when SOG is used for the resist 80, the residue of the resist 80 is removed by the RIE method using a fluorine-based gas, leaving only the imprinted pattern on the magnetic film. Here, the residue indicates a resist portion that is removed to form a resist pattern. CF ₄ or SF ₆ is preferable as a gas that is a raw material for RIE. For example, when the thickness of the resist 80 is 80 nm and the pattern height is 50 nm, the residue of the resist 80 is about 50 nm. When CF ₄ gas is used as the conditions for the RIE method, the gas flow rate is 20 sccm, the pressure is 0.1 Pa, Etching may be performed with a bias of 100 W. Further, when a fluorine-based gas is used, an acid such as HF or H ₂ SO ₄ may be generated by reacting with water in the atmosphere, and thus washing with water is performed. The plasma source is preferably ICP (Inductively Coupled Plasma) capable of generating high-density plasma at a low pressure, but may be ECR (Electron Cyclotron Resonance) plasma or a general parallel plate RIE apparatus.

Next, as shown in FIG. 6, the protective layer 60, the second magnetic layer 50, and the exchange coupling control layer 40 are processed by ion milling. For processing, etching using an Ar ion beam (Ar ion milling) is generally used, but He, Ne, or a mixed gas of Ar, He, Ne and O ₂ , N _2, or the like may be used. Specifically, ion milling using an ECR ion gun is attempted. In this method, etching with a static counter-type (ion incident angle of 90 °) can be processed with almost no taper (tilt) on the magnetic material unevenness. For example, when 10 nm etching with Ar gas is performed using an ECR ion gun, etching is preferably performed for 60 seconds with a gas flow rate of 10 sccm, a pressure of 10 mPa, Power of 100 W, and an acceleration voltage of 500 V. When a mixed gas of He and N ₂ is used, etching is preferably performed with a He gas flow rate of 10 sccm, an N ₂ gas flow rate of 10 sccm, a pressure of 10 mPa, Power 1000 W, and an acceleration voltage of 500 V.

When SOG is used as a resist mask, that is, an etching mask, it is necessary to remove the etching mask by the RIE method using a fluorine-based gas in the same manner as the residue removal of the resist 80. FIG. 7 shows the process diagram. As RIE conditions, for example, when CF ₄ gas is used, it is preferable to perform etching without applying a bias at a gas flow rate of 20 sccm and a pressure of 0.1 Pa. Further, the step of removing the resist 80 includes a step of demagnetizing the magnetic component of the first magnetic layer 30 in the groove. The degree of demagnetization can be controlled by the RIE time.

In addition, when processing the second magnetic layer 50 and the exchange coupling control layer 40 using ion milling, when a mixed gas of He and N ₂ is used, a process of demagnetizing the magnetic component is simultaneously performed. Therefore, this process time can be shortened.

  Next, the protective layer 60 is removed. An example of the removal method is an RIE method using oxygen gas.

  Finally, a protective layer 60 is formed to protect the surface of the processed medium as shown in FIG. Carbon is used for forming the protective layer 60. As a film forming method, a CVD method is preferable because coverage to unevenness is improved, but a sputtering method, a vacuum evaporation method, or the like may be used. When the protective layer 60 is formed by the CVD method, a DLC film containing many sp3 carbon bonds is formed. The film thickness is preferably 1 to 10 nm. Of course, a lubricating layer (not shown) can be formed on the protective layer 60. As the lubricating layer, perfluoropolyether, fluorinated alcohol, fluorinated carboxylic acid, or the like can be used.

  According to the present embodiment, it is possible to provide a magnetic recording medium using an ECC medium whose recording layer has excellent corrosion resistance.

(Second Embodiment)
FIG. 9 shows an embodiment in which a DTR magnetic recording medium using an ECC medium is applied to an HDD. The HDD 90 in the present embodiment includes a hub 110 driven by a spindle motor (not shown) in the housing 100, a DTR medium 120 fixed to the hub 110 and rotated, and a swing arm driven by an actuator (not shown). 130 and a head unit 140 that reads and writes information on the DTR medium 120. In the present embodiment, the ECC medium in the first embodiment is used as the DTR medium 120.

  According to the ECC medium according to the present embodiment, a magnetic recording medium having a recording layer with excellent corrosion resistance can be provided.

  The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific embodiments, and various modifications and changes can be made within the technical scope described in the claims. .

  Hereinafter, the present invention will be specifically described based on examples and comparative examples.

  The performance evaluation of the DTR medium manufactured using the first embodiment according to the present invention was performed. Specifically, in order to examine the side damage, the DTR medium was mounted on the HDD 90, the head unit 140 was moved in the cross-track direction, and the track unit magnetic body width was examined. In addition, the track part magnetic body width was normalized with 60 nm as 1.

Next, after allowing the DTR medium to stand under high temperature and high humidity (70 ° C, 80%) for 24 hours, 1 mL of dilute nitric acid was dropped on the surface of the DTR medium, and the dilute nitric acid dropped after 1 hour was sucked out. The amount of Co elution (μg / m ² ) was determined by collecting and performing elemental analysis using an inductively coupled plasma mass spectrometer.

Generally, a magnetic recording medium excellent in error rate resistance is provided if the standard value of the track portion magnetic body width is 0.9 (ie, 54 nm) or more and the Co elution amount is smaller than 1 μg / m ^2. It is.

In the configuration of the recording layer 70 of the DTR medium, CoCrPt was used for the first magnetic layer 30, Pt—SiO ₂ was used for the exchange coupling control layer 40, and Co was used for the second magnetic layer 50. The film thicknesses were 10 nm, 1 nm, and 5 nm, respectively. The Ku value obtained for the first magnetic layer 30 was 6 × 10 ⁶ erg / cm ³ , and the Ku value obtained for the second magnetic layer 50 was 9 × 10 ⁴ erg / cm ³ . Further, for ion milling and demagnetization of the magnetic component, etching was performed using a mixed gas of He and N ₂ to produce a DTR medium.

  10, 11, and 12 show the results of performance evaluation performed on the DTR medium manufactured according to the first embodiment based on the following examples.

  The conditions are shown in Examples 1-1 to 8-1 in FIGS. 10, 11 and 12 below.

The experimental results in FIG. 12 show the results of evaluating a DTR medium produced using Ar gas for ion milling and CF ₄ gas for demagnetizing the magnetic component.

In Example 1-1 to Example 8-1, the material is set based on the condition that the mass number of the element is m ₁ <m ₂ .

Example 1
For the first magnetic layer 30, SiO ₂ was used as a material for separating the grain state of the magnetic layer. Further, TiO ₂ , Cr ₂ O ₃ , NbO ₂ , MoO ₂ , HfO ₂ , Ta ₂ O ₅ , and WO ₃ were used for the second magnetic layer 50.

A sufficient track width with a track width standard value of 0.9 or more was obtained, the required amount of Co was less than 1 μg / m ² , and good results were obtained with respect to corrosion resistance.

(Example 2)
TiO ₂ is used as a material for separating the grain state of the first magnetic layer 30, and Cr ₂ O ₃ , NbO ₂ , MoO ₂ , HfO ₂ , Ta ₂ O are used as materials for separating the grain state of the second magnetic layer 50. ₅ and WO _{3 were} used.

A sufficient track width with a track width standard value of 0.9 or more was obtained, the required amount of Co was less than 1 μg / m ² , and good results were obtained with respect to corrosion resistance.

(Example 3)
Cr ₂ O ₃ is used as a material for separating the grain state of the first magnetic layer 30, and NbO ₂ , MoO ₂ , HfO ₂ , Ta ₂ O ₅ , WO are used as materials for separating the grain state of the second magnetic layer 50. _{3 were} used.

A sufficient track width with a track width standard value of 0.9 or more was obtained, the required amount of Co was less than 1 μg / m ² , and good results were obtained with respect to corrosion resistance.

Example 4
NbO ₂ was used as a material for separating the grain state of the first magnetic layer 30, and MoO ₂ , HfO ₂ , Ta ₂ O ₅ , and WO _{3 were} used as materials for separating the grain state of the second magnetic layer 50.

A sufficient track width with a track width standard value of 0.9 or more was obtained, the required amount of Co was less than 1 μg / m ² , and good results were obtained with respect to corrosion resistance.

(Example 5)
MoO ₂ was used as a material for separating the grain state of the first magnetic layer 30, and HfO ₂ , Ta ₂ O ₅ , and WO _{3 were} used as materials for separating the grain state of the second magnetic layer 50.

A sufficient track width with a track width standard value of 0.9 or more was obtained, the required amount of Co was less than 1 μg / m ² , and good results were obtained with respect to corrosion resistance.

(Example 6)
HfO ₂ was used as a material for separating the grain state of the first magnetic layer 30, and Ta ₂ O ₅ and WO _{3 were} used as a material for separating the grain state of the second magnetic layer 50.

A sufficient track width with a track width standard value of 0.9 or more was obtained, the required amount of Co was less than 1 μg / m ² , and good results were obtained with respect to corrosion resistance.

(Example 7)
Ta ₂ O ₅ was used as a material for separating the grain state of the first magnetic layer 30, and WO _{3 was} used as a material for separating the grain state of the second magnetic layer 50.

A sufficient track width with a track width standard value of 0.9 or more was obtained, the required amount of Co was less than 1 μg / m ² , and good results were obtained with respect to corrosion resistance.

(Example 8)
SiO ₂ was used as a material for separating the magnetic state of the first magnetic layer 30, and TiO ₂ was used as a material for separating the grain state of the second magnetic layer 50.

A sufficient track width with a track width standard value of 0.9 or more was obtained, the required amount of Co was less than 1 μg / m ² , and good results were obtained with respect to corrosion resistance.

  Next, the results of performance evaluation based on the following comparative example for the DTR medium manufactured according to the first embodiment will be shown.

  The conditions are shown in Comparative Examples 1-1 to 10-2 in FIGS.

Further, the experimental results of FIG. 15 show the results of evaluating a DTR medium produced using Ar gas for ion milling and CF ₄ gas for demagnetization of the magnetic component.

In Comparative Example 1-1 to Comparative Example 10-2, the material is set based on the condition that the mass number of the element is m ₁ ≧ m ₂ .

(Comparative Example 1)
For both the first magnetic layer 30 and the second magnetic layer 50, SiO _{2 was} used as a material for separating the grain state.

Due to the decrease in the width of the magnetic material due to side damage, the standard value of the track width became smaller than 0.9. In addition, the required amount of Co was more than 1 μg / m ² .

(Comparative Example 2)
TiO ₂ was used as a material for separating the grain state of the first magnetic layer 30, and SiO ₂ and TiO ₂ were used as a material for separating the grain state of the second magnetic layer 50.

When both the first magnetic layer 30 and the second magnetic layer 50 are made of TiO ₂ as a material that separates the grain state, the standard value of the track width is less than 0.9 due to a decrease in the width of the magnetic material due to side damage. It has become smaller. In addition, the required amount of Co was more than 1 μg / m ² .

Next, when TiO ₂ is used as a material for separating the grain state of the first magnetic layer 30 and SiO ₂ is used as a material for separating the grain state of the second magnetic layer 50, the required amount of Co is Less than 1 μg / m ² . However, the standard value of the track width has become smaller than 0.9 due to a significant reduction in the width of the magnetic material due to side damage.

(Comparative Example 3)
Cr ₂ O ₃ was used as a material for separating the grain state of the first magnetic layer 30, and SiO ₂ , TiO ₂ , and Cr ₂ O ₃ were used as materials for separating the grain state of the second magnetic layer 50.

When both the first magnetic layer 30 and the second magnetic layer 50 are made of Cr ₂ O ₃ as a material for separating the grain state, the standard value of the track width is 0.9 due to the decrease in the width of the magnetic material due to side damage. Became smaller. In addition, the required amount of Co was more than 1 μg / m ² .

Next, when Cr ₂ O ₃ is used as a material for separating the grain state of the first magnetic layer 30 and SiO ₂ or TiO ₂ is used as a material for separating the grain state of the second magnetic layer 50, The amount of Co required was less than 1 μg / m ² . However, the standard value of the track width has become smaller than 0.9 due to a significant reduction in the width of the magnetic material due to side damage.

(Comparative Example 4)
NbO ₂ was used as the material for separating the grain state of the first magnetic layer 30, and SiO ₂ , TiO ₂ , Cr ₂ O ₃ , and NbO ₂ were used as the material for separating the grain state of the second magnetic layer 50.

When NbO ₂ is used as the material for separating the grain state in both the first magnetic layer 30 and the second magnetic layer 50, the standard value of the track width is more than 0.9 due to a decrease in the magnetic body width due to side damage. It has become smaller. In addition, the required amount of Co was more than 1 μg / m ² .

Next, when NbO ₂ is used as a material for separating the grain state of the first magnetic layer 30, and SiO ₂ , TiO ₂ , Cr ₂ O ₃ is used as a material for separating the grain state of the second magnetic layer 50. The amount of Co required was less than 1 μg / m ² . However, a significant decrease in the width of the magnetic material due to side damage was observed, and the standard value of the track width was smaller than 0.9.

(Comparative Example 5)
The MoO ₂ used as a material for separating the particle state of the first magnetic layer _{30, SiO 2, TiO 2,} Cr 2 O 3 to the material that separates the particle state of the second magnetic layer _50, the NbO 2, MoO ₂ Using.

When both the first magnetic layer 30 and the second magnetic layer 50 are made of MoO ₂ as a material for separating the grain state, the standard value of the track width is more than 0.9 due to a decrease in the width of the magnetic material due to side damage. It has become smaller. In addition, the required amount of Co was more than 1 μg / m ² .

Next, MoO ₂ is used as a material for separating the grain state of the first magnetic layer 30, and SiO ₂ , TiO ₂ , Cr ₂ O ₃ , and NbO ₂ are used as materials for separating the grain state of the second magnetic layer 50. When used, the required amount of Co was less than 1 μg / m ² . However, a significant decrease in the width of the magnetic material due to side damage was observed, and the standard value of the track width was smaller than 0.9.

(Comparative Example 6)
HfO ₂ is used as a material for separating the grain state of the first magnetic layer 30, and SiO ₂ , TiO ₂ , Cr ₂ O ₃ , NbO ₂ , MoO ₂ , as a material for separating the grain state of the second magnetic layer 50, HfO ₂ was used.

When HfO ₂ is used as the material for separating the grain state in both the first magnetic layer 30 and the second magnetic layer 50, the standard value of the track width is less than 0.9 due to the decrease in the magnetic body width due to side damage. It has become smaller. In addition, the required amount of Co was more than 1 μg / m ² .

Next, HfO ₂ is used as a material for separating the grain state of the first magnetic layer 30, and SiO ₂ , TiO ₂ , Cr ₂ O ₃ , NbO ₂ , and the like are used as materials for separating the grain state of the second magnetic layer 50. When MoO ₂ was used, the required amount of Co was less than 1 μg / m ² . However, a significant decrease in the width of the magnetic material due to side damage was observed, and the standard value of the track width was smaller than 0.9.

(Comparative Example 7)
Ta ₂ O ₅ is used as a material for separating the grain state of the first magnetic layer 30, and SiO ₂ , TiO ₂ , Cr ₂ O ₃ , NbO ₂ , MoO are used as materials for separating the grain state of the second magnetic layer 50. ₂ , HfO ₂ and Ta ₂ O ₅ were used.

When Ta ₂ O ₅ is used as the material for separating the grain state in both the first magnetic layer 30 and the second magnetic layer 50, the standard value of the track width is 0.9 due to the decrease in the magnetic body width due to side damage. Became smaller. In addition, the required amount of Co was more than 1 μg / m ² .

Next, Ta ₂ O ₅ is used as a material for separating the grain state of the first magnetic layer 30, and SiO ₂ , TiO ₂ , Cr ₂ O ₃ , and NbO are used as materials for separating the grain state of the second magnetic layer 50. _{2 When} MoO ₂ was used, the required amount of Co was less than 1 μg / m ² . However, a significant decrease in the width of the magnetic material due to side damage was observed, and the standard value of the track width was smaller than 0.9.

(Comparative Example 8)
WO ₃ is used as a material for separating the grain state of the first magnetic layer 30, and SiO ₂ , TiO ₂ , Cr ₂ O ₃ , NbO ₂ , MoO ₂ , and the like are used as materials for separating the grain state of the second magnetic layer 50. with _{HfO 2, Ta 2 O 5,} WO 3.

When both the first magnetic layer 30 and the second magnetic layer 50 are made of WO ₃ as a material for separating the grain state, the standard value of the track width is more than 0.9 due to a decrease in the width of the magnetic material due to side damage. It has become smaller. In addition, the required amount of Co was larger than μg / m ² .

Next, WO ₃ is used as a material for separating the grain state of the first magnetic layer 30, and SiO ₂ , TiO ₂ , Cr ₂ O ₃ , NbO ₂ , and the like are used as materials for separating the grain state of the second magnetic layer 50. When MoO ₂ and Ta ₂ O ₅ were used, the required amount of Co was less than 1 μg / m ² . However, a significant decrease in the width of the magnetic material due to side damage was observed, and the standard value of the track width was smaller than 0.9.

(Comparative Example 9)
For both the first magnetic layer 30 and the second magnetic layer 50, SiO ₂ was used as a material for separating the grain state.

  The magnetic band width decreased due to side damage, and the standard value of the track width was smaller than 0.9.

(Comparative Example 10)
TiO ₂ was used as a material for separating the grain state of the first magnetic layer 30, and SiO ₂ and TiO ₂ were used as a material for separating the grain state of the second magnetic layer 50. When TiO ₂ is used as the material for separating the grain state in both the first magnetic layer 30 and the second magnetic layer 50, a decrease in the magnetic body width due to side damage is observed, and the standard value of the track width is 0.9. Became smaller.

When TiO ₂ is used as the material that separates the grain state of the first magnetic layer 30 and SiO ₂ is used as the material that separates the grain state of the second magnetic layer 50, the width of the magnetic material due to side damage is greatly increased. As a result, the standard value of the track width became smaller than 0.9.

  In this example and this comparative example, an oxide was used as a material for separating the grain state of the magnetic layer, but similar results were obtained when a nitride was used.

1 is a cross-sectional view showing a configuration of a DTR medium according to a first embodiment of the present invention. 1 is a cross-sectional view showing a configuration of a DTR medium according to a first embodiment of the present invention. The figure which shows the manufacturing process of the DTR medium concerning the 1st Embodiment of this invention. The figure which shows the manufacturing process of the DTR medium concerning the 1st Embodiment of this invention. The figure which shows the manufacturing process of the DTR medium concerning the 1st Embodiment of this invention. The figure which shows the manufacturing process of the DTR medium concerning the 1st Embodiment of this invention. The figure which shows the manufacturing process of the DTR medium concerning the 1st Embodiment of this invention. The figure which shows the manufacturing process of the DTR medium concerning the 1st Embodiment of this invention. 1 is a diagram showing a configuration of an HDD using a DTR medium according to a first embodiment of the present invention. The result figure of the performance evaluation of the DTR medium concerning the 1st Embodiment of this invention. The result figure of the performance evaluation of the DTR medium concerning the 1st Embodiment of this invention. The result figure of the performance evaluation of the DTR medium concerning the 1st Embodiment of this invention. The result figure of the performance evaluation of the DTR medium concerning the 1st Embodiment of this invention. The result figure of the performance evaluation of the DTR medium concerning the 1st Embodiment of this invention. The result figure of the performance evaluation of the DTR medium concerning the 1st Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Board | substrate 20 ... Soft magnetic layer 30 ... 1st magnetic layer 40 ... Exchange coupling control layer 50 ... 2nd magnetic layer 60 ... Protective layer 70 ... Recording layer 80 ... Resist 90 ... HDD
DESCRIPTION OF SYMBOLS 100 ... Case 110 ... Hub 120 ... DTR medium 130 ... Swing arm 140 ... Head part

Claims (5)

A substrate,
A soft magnetic layer formed on the substrate;
A first magnetic layer comprising a compound M ₁ X formed on the soft magnetic layer;
A nonmagnetic layer formed to cover a part of the surface of the first magnetic layer;
A second magnetic layer containing the compound M ₂ X formed on the nonmagnetic layer;
A protective layer formed on the second magnetic layer;
A magnetic recording medium comprising:
The M ₁ and the M ₂ are elements selected from Si, Ti, Cr, Ta, W, Hf, Nb, and Mo;
X is an element selected from O and N;
Mass number _{m 1} of the _{M 1,} the mass number of the _{M 2} as _{m 2,} and characterized by having the _{M 1,} the relationship mass number of selected elements in the _{M 2} is _m 1 _{<m 2} Magnetic recording media. Laminating a soft magnetic layer on a substrate;
Laminating a first magnetic layer containing compound M ₁ X on the soft magnetic layer;
Laminating a nonmagnetic layer on the first magnetic layer;
Laminating a second magnetic layer containing the compound M ₂ X on the nonmagnetic layer;
Laminating a protective layer on the second magnetic layer;
Applying a resist on the protective layer;
Transferring irregularities using a stamper to the resist;
Removing the resist residue to form a resist pattern;
Processing using the resist pattern as a mask, and forming irregularities on the nonmagnetic layer, the second magnetic layer, and the protective layer;
Removing the resist and the protective layer;
Forming a protective layer on the second magnetic layer;
Of the compound M ₁ X and the compound M ₂ X,
M ₁ and M ₂ are elements selected from Si, Ti, Cr, Ta, W, Hf, Nb, and Mo,
X is an element selected from O and N;
The mass number of M ₁ is m ₁ , the mass number of M ₂ is m ₂ , and the mass numbers of selected elements of M ₁ and M ₂ have a relationship of m ₁ <m _2. A method of manufacturing a magnetic recording medium. The compound M ₁ X is SiO ₂ ;
The magnetic recording medium according to claim 1, wherein the compound M ₂ X is any one of TiO ₂ , Cr ₂ O ₃ , NbO ₂ , MoO ₂ , HfO ₂ , Ta ₂ O ₅ , and WO ₃ . The compound M ₁ X is TiO ₂ ,
The magnetic recording medium according to claim 1, wherein the compound M ₂ X is any one of Cr ₂ O ₃ , NbO ₂ , MoO ₂ , HfO ₂ , Ta ₂ O ₅ , and WO ₃ . A soft magnetic layer;
A first magnetic layer comprising a compound M ₁ X formed on the soft magnetic layer;
A nonmagnetic layer formed to cover a part of the surface of the first magnetic layer;
A second magnetic layer containing the compound M ₂ X formed on the nonmagnetic layer;
A protective layer formed on the second magnetic layer;
With
The M ₁ and the M ₂ are elements selected from Si, Ti, Cr, Ta, W, Hf, Nb, and Mo;
X is an element selected from O and N;
The mass number of M ₁ is m ₁ , the mass number of M ₂ is m ₂ , and the mass numbers of selected elements of M ₁ and M ₂ are m ₁ <m _2. A magnetic recording medium,
A magnetic recording / reproducing head for recording / reproducing information on the magnetic recording medium;
A magnetic recording / reproducing apparatus comprising:

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