JP2009099182A - Magnetic recording medium, magnetic recording/reproducing apparatus, and method for manufacturing magnetic recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic recording medium manufacturing method forming in a recording layer a non-magnetic portion having substantially no coercive force or saturated magnetization, and easily providing a recording medium having excellent magnetic characteristics. <P>SOLUTION: The method includes forming the recording layer 13' made of CrPt<SB>3</SB>on a substrate 11, forming a mask pattern layer 15' on a surface of the recording layer 13', and irradiating each portion of the recording layer 13' exposed from the mask pattern layer 15' with ions. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a magnetic recording medium such as a so-called discrete track medium or a patterned medium, a magnetic recording / reproducing apparatus including the magnetic recording medium, and a method for manufacturing the magnetic recording medium.

  In the technical field of magnetic disks, as a preferable medium for achieving a high recording density, a partial nonmagnetic portion is formed on a recording layer serving as a recording area, such as a so-called discrete track medium (DTM) or patterned medium (PM). 2. Description of the Related Art Magnetic disks having a known structure are known. These magnetic disks are described, for example, in Patent Documents 1 to 3 below.

  As a method for manufacturing such a magnetic disk, for example, as shown in Patent Document 4 below, a method is known in which nonmagnetic portions are formed in various portions of a recording layer by ion implantation. In this manufacturing method, a recording layer made of FePt and an ion buffer layer are sequentially formed on a substrate, a stencil mask is formed on the surface of the ion buffer layer, and ions are implanted into each part of the recording layer exposed from the stencil mask. ing. As a result, portions of the recording layer subjected to ion implantation are formed as nonmagnetic portions. According to such a manufacturing method, a flat recording layer partially having a nonmagnetic portion can be formed without mechanically processing the recording layer.

JP-A-2005-71467 JP 2005-166115 A JP 2005-293730 A JP 2006-309841 A

  However, in the above-described conventional manufacturing method, since the material constituting the recording layer is made of FePt, the coercive force of the portion that becomes the nonmagnetic portion is not reduced to a sufficiently desired level even by ion implantation, and a certain degree of coercive force. Therefore, there is a problem that a recording medium having excellent magnetic properties cannot be obtained.

  The present invention has been conceived under the circumstances described above, and can form a non-magnetic portion having almost no coercive force or saturation magnetization on a recording medium, so that a recording layer having excellent magnetic properties can be easily formed. It is an object of the present invention to provide a magnetic recording medium, a magnetic recording / reproducing apparatus including the magnetic recording medium, and a method for manufacturing the magnetic recording medium.

  In order to solve the above problems, the present invention takes the following technical means.

The magnetic recording medium provided by the first aspect of the present invention has a recording magnetic part capable of magnetically recording information and a nonmagnetic part not magnetically recordable in the recording layer formed on the substrate, The recording magnetic part is made of a Cu ₃ Au type ordered alloy, and the non-magnetic part is made of a disordered alloy.

Preferably, as a Cu ₃ Au type ordered alloy in the recording magnetic part, a main component corresponding to Au is made of Cr, and a main component corresponding to Cu is made of Pt.

Preferably, the Cu ₃ Au type ordered alloy has a <111> crystal axis in the thickness direction of the recording layer.

Preferably, the Cu ₃ Au type ordered alloy has an easy axis of magnetization in the thickness direction of the recording layer.

Preferably, the Cu ₃ Au type ordered alloy has an easy axis of magnetization in the thickness direction of the recording layer due to a magnetostrictive effect.

  The magnetic recording medium provided by the second aspect of the present invention has a recording magnetic part capable of magnetically recording information and a nonmagnetic part not magnetically recordable in the recording layer formed on the substrate, The recording magnetic part is made of a NiAs type ordered alloy, and the nonmagnetic part is made of a disordered alloy.

  The magnetic recording / reproducing apparatus provided by the third aspect of the present invention includes a magnetic recording medium according to the first or second aspect, a magnetic head for recording and reproducing information on the magnetic recording medium, and the magnetic recording medium. A motor for rotating the recording medium and a head moving mechanism for moving the magnetic head on the magnetic recording medium are provided.

A method of manufacturing a magnetic recording medium provided by the fourth aspect of the present invention includes a step of forming a recording layer made of CrPt ₃ on a substrate, a step of forming a mask pattern layer on the surface of the recording layer, And irradiating each part of the recording layer exposed from the mask pattern layer with ions.

  Preferably, the method includes a step of heating after depositing Cr and Pt on the substrate.

  Preferably, after the Cr layer and the Pt layer are alternately laminated on the substrate, the recording layer is formed by performing a heat treatment.

According to such a configuration, since the recording layer made of, for example, CrPt ₃ is irradiated with ions, the portion of the recording layer irradiated with ions can be formed as a nonmagnetic portion having almost no coercive force or saturation magnetization, A recording medium having excellent magnetic properties can be easily obtained.

  Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

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

  FIG. 1 is an internal structure diagram showing an embodiment of a magnetic recording / reproducing apparatus according to the present invention. As shown in the figure, a magnetic recording / reproducing apparatus A is disposed so as to face a spindle motor (not shown), a rotating shaft 1 rotated by the spindle motor, a magnetic disk X mounted on the rotating shaft 1, and a magnetic disk X. A swing arm 4 having a magnetic head H at the tip, an arm shaft 3, a swing arm 4 that is fixed to the tip and moves horizontally on the magnetic disk X around the arm shaft 5, and a swing arm An actuator 5 for driving 4 to move horizontally is provided. The flying head slider 2, the arm shaft 3, the swing arm 4, and the actuator 5 are configured as a head moving mechanism that moves the magnetic head H on the magnetic disk X.

  When recording or reproducing information with respect to the magnetic disk X, the swing arm 4 is driven by the actuator 5 constituted by a magnetic circuit, and the magnetic head H provided at the tip of the flying head slider 2 is rotated. It is positioned at a desired track on a certain magnetic disk X. In the magnetic head H, a recording element and a read element are formed. The recording core width of the recording element is about 60 nm, and the recording gap length in the disk radial direction is about 30 nm. The read core width of the read element is about 60 nm, and the read gap length in the disk radial direction is 27 nm.

  2 and 3 show the magnetic disk X provided in the magnetic recording / reproducing apparatus A of FIG. This magnetic disk X is obtained by the manufacturing method according to the present invention. FIG. 2 is a perspective view of the magnetic disk X, and FIG. 3 is a partially enlarged sectional view of the magnetic disk X.

  The magnetic disk X has a laminated structure including a substrate 11, a soft magnetic layer 12, a recording layer 13, and a protective film 14 (not shown in FIG. 2), and is configured as a patterned medium.

The substrate 11 is a part for ensuring the rigidity of the magnetic disk X, and is made of, for example, SiO ₂ , aluminum alloy, glass, or resin.

  The soft magnetic layer 12 is for efficiently forming a magnetic path for returning the magnetic flux from the magnetic head acting during recording to the magnetic head again. Such a soft magnetic layer 12 is made of a soft magnetic material having a high magnetic permeability, a large saturation magnetization, and a small coercive force. Examples of the soft magnetic material constituting the soft magnetic layer 12 include FeC, FeNi, FeCoB, FeCoSiC, CoZrNb, FeCoZrNb, and FeCo—AlO. The thickness of the soft magnetic layer 12 is, for example, 10 to 200 nm.

As shown in FIG. 3, the recording layer 13 has a plurality of recording magnetic portions 13A and a plurality of nonmagnetic portions 13B. The recording magnetic portion 13A has perpendicular magnetic anisotropy and corresponds to an information recording portion in which the magnetization direction is upward or downward. The nonmagnetic portion 13B has nonmagnetic magnetic characteristics in which the coercive force (Hc) or the saturation magnetization value (Ms) is 0, and magnetic recording cannot be performed on this portion. The recording layer 13 is a continuous film body, and both the recording magnetic part 13A and the nonmagnetic part 13B are made of the same material. However, the non-magnetic portion 13B is a portion that has been altered to a non-magnetic material. The material constituting the recording layer 13 of the present embodiment is made of a Cu ₃ Au type ordered alloy, the main component corresponding to Au is Cr, and the main component corresponding to Cu is Pt. That is, the recording layer 13 is made of CrPt ₃ . The thickness of the recording layer 13 is about 5 to 20 nm.

As the Cu ₃ Au type ordered alloy, CrPt ₃ , FePt ₃ , CoPt ₃ , MnPt ₃ , MnPd ₃ , Mn ₃ Pt and the like are known. Of these, FePt ₃ , MnPd ₃ , and Mn ₃ Pt are not suitable as magnetic recording materials because they exhibit antiferromagnetism and are not substantially magnetized. CrPt ₃ , CoPt ₃ , and MnPt ₃ are suitable as magnetic recording materials because they have ferromagnetism. For example, a CrPt ₃ film formed on a SiO ₂ substrate and subjected to heat treatment has a negative magnetostriction constant with regular atomic arrangement, and receives tensile stress from the SiO ₂ substrate. Thus, the CrPt ₃ film has an easy axis of magnetization in the direction perpendicular to the film surface. Such an ordered alloy is suitable as a material for locally forming an ordered / random region. The relationship between the magnetic anisotropy constant Ku, the magnetostriction constant λ, and the stress σ is Ku = −3 / 2 × λ × σ. Here, a Cu ₃ Au type ordered alloy thin film made of CrPt ₃ has λ: negative, σ: positive, and Ku has a positive value, so that perpendicular magnetic anisotropy appears. Therefore, the recording magnetic part 13A in the recording layer 13 of the present embodiment has perpendicular magnetic anisotropy in which the magnetization direction is upward or downward.

The protective film 14 is a part for physically and chemically protecting the soft magnetic layer 12 and the recording layer 13 from the outside, and is made of, for example, SiN, SiO ₂ , or diamond-like carbon. The exposed surface of the protective film 14 forms a recording surface of the magnetic disk X, and a lubricant is applied to this surface.

  In the laminated structure of the magnetic disk X composed of the substrate 11, the soft magnetic layer 12, the recording layer 13, and the protective film 14 as described above, other layers may be included as necessary. For example, a nonmagnetic intermediate layer or the like may be provided between the substrate 11 and the recording layer 13 in addition to the soft magnetic layer 12.

  When information is recorded on such a magnetic disk X, a recording magnetic head (not shown) is floated on the protective film 14, and recording on the recording layer 13 is performed by applying a recording magnetic field by the magnetic head. A recording mark (magnetic domain) indicating a predetermined magnetization direction is formed on the magnetic part 13A. At this time, the recording magnetic part 13A to which the magnetic field is applied while the information recording is in progress and the recording magnetic part 13A adjacent to both are separated by the nonmagnetic part 13B. The cross light phenomenon that the mark disappears or deteriorates is suppressed. A magnetic disk in which the cross-write phenomenon is suppressed is preferable for reducing the track pitch and increasing the recording density. Note that the magnetization of the servo region used for tracking servo or the like is aligned in a predetermined direction by an external permanent magnet or the like at the time of manufacture. When recording layers are formed on both sides, the recording layers are magnetized so that the magnetization directions of the front and back surfaces are opposite to each other.

Such a magnetic disk X was magnetically recorded and reproduced by a recording / reproducing tester. In the recording / reproducing test, a magnetic field perpendicular to the magnetic disk X was applied. Thereby, the magnetization of the magnetic part (recording magnetic part 13A) as a Cu ₃ Au type ordered alloy is directed upward or downward in the vertical direction. With respect to the magnetic disk X thus recorded, the reproduction signal was examined as shown in FIG. Here, the dot length prepared for the signal confirmation is 50 nm to 200 nm. As shown in the figure, a magnetic signal can be detected from the recording magnetic part 13A not irradiated with ions, and a magnetic signal cannot be detected from the nonmagnetic part 13B irradiated with ions. This is because the portion that was not irradiated with ions developed magnetization while maintaining the original Cu ₃ Au type ordered alloy, whereas the portion that was irradiated with ions was Cu ₃ Au type ordered. It means that the alloy is disturbed and becomes an irregular alloy. As shown in the figure, when the recording layer 13 is magnetized upward, the signal waveform of the reproduction signal swings to the plus side, whereas when it is magnetized downward, the signal waveform of the reproduction signal is minus side. Swing. Similar signal waveforms are obtained during actual recording and reproduction. The signal output is 0 in the region where the nonmagnetic portion 13B having no Cu ₃ Au type ordered alloy structure continues continuously.

  5 to 7 show a method of manufacturing the magnetic disk X. This method corresponds to one embodiment of the method for manufacturing a magnetic recording medium according to the present invention.

In this method, first, as shown in FIG. 5A, a soft magnetic layer 12 and a recording layer 13 ′ are sequentially formed on a substrate 11. As the substrate 11, a SiO ₂ substrate was used. The thickness of the substrate 11 is 0.635 mm, the outer diameter is φ65 mm, the inner diameter is φ20 mm, and the shape of the substrate 11 is a donut shape. The soft magnetic layer 12 is formed by, for example, a sputtering method. The recording layer 13 ′ is in an intermediate generation state before the above-described recording magnetic portion 13A and nonmagnetic portion 13B are formed, and is formed as follows.

As shown in FIG. 7, the substrate 11 on which the soft magnetic layer 12 is formed is disposed on the rotary table 20 with the soft magnetic layer 12 facing upward, and the Cr target 21 and the Pt target are placed on the substrate 11. 22 is used to perform sputtering. At this time, the ultimate degree of vacuum is, for example, 5 × 10 ⁻⁶ Pa, and the vacuum degree is set to about 0.5 Pa by introducing Ar during film formation. The turntable 20 is rotated at a rotation speed of about 10 rpm, and the power supplied to the Cr target 21 and the Pt target 22 is 100 W and 300 W, respectively. While the substrate 11 rotates at a low speed together with the turntable 20, sputtering is performed with the Cr target 21 and the Pt target 22. Thereby, Cr layers 13c ′ and Pt layers 13p ′ are alternately stacked on the surface of the soft magnetic layer 12. The Cr layer 13c ′ is formed with a film thickness of about 0.4 nm per rotation, and the Pt layer 13p ′ is formed with a film thickness of about 1.6 nm per rotation.

For example, sputtering is performed while the substrate 11 is rotated a predetermined number of times, and as a result, the Cr layer 13c ′ and the Pt layer 13p ′ are alternately and repeatedly stacked on the substrate 11. The state in which the Cr layer 13c ′ and the Pt layer 13p ′ are alternately stacked is referred to as a so-called as-depo state. For example, sputtering is performed for about 1 minute at a sputtering rate of about 20 nm / min. As a result, a CrPt ₃ recording layer 13 ′ having a thickness of about 20 nm and a Cr: Pt composition ratio of 1: 3 is formed. When the magnetic characteristics of the recording layer 13 ′ thus formed were measured with a VSM (Vibrating Sample MAgnetomer), no magnetism was shown and the saturation magnetization Ms was zero. However, since the recording layer 13 ′ contains about 75 at% of Pt, the <111> axial direction with respect to the dense structure of the fcc structure was grown. The <111> axis direction is the direction of the easy magnetization axis.

  Thereafter, the substrate 11 is heat-treated in a vacuum. The heating temperature is, for example, 400 to 900 ° C., and the heating time is about 15 minutes. Through such heat treatment, a recording layer 13 ′ having a predetermined magnetic property and a predetermined thickness is formed on the surface of the soft magnetic layer 12 in the substrate 11.

Specifically, heat treatment was performed at 850 ° C. for 15 minutes using a vacuum annealing furnace. By this heat treatment, it was found that the recording layer 13 ′ made of CrPt ₃ alloy was made of Cu ₃ Au type ordered alloy as a result of crystal identification by X-ray diffraction. When the magnetic properties of this ordered alloy were measured by VSM, the value of saturation magnetization Ms was about 300 emu / cc, the coercive force Hc was about 6 kOe, and perpendicular magnetic anisotropy was exhibited. When the magnetic anisotropy constant was measured with a torque meter, it showed a large perpendicular magnetic anisotropy of 6 × 10 ⁶ erg / cc. The recording layer 13 ′ thus formed through the heat treatment has a face-centered cubic lattice crystal structure as shown in FIG. In such a face-centered cubic lattice, Cr atoms are located at each vertex of the unit lattice, Pt atoms are located at the center of each surface of the unit lattice, and the number of atoms in the unit lattice is one Cr atom. There are 3 atoms. That is, the constituent material of the recording layer 13 ′ is CrPt ₃ . Such a crystal structure in which atoms are regularly arranged is called an ordered alloy. In the as-depo state, the recording layer 13 ′ has no magnetization because it is simply a stacked state of the Cr layer 13c ′ and the Pt layer 13p ′. On the other hand, in the recording layer 13 ′ that is an ordered alloy, the magnetic moment of Cr alone is about 2.33 ± 0.10 μB, and the magnetic moment of Pt alone is about −0.27 ± 0.05 μB. In such a face-centered cubic lattice crystal structure, a {111} plane that is a dense plane is a growth plane. The direction of the crystal axis <111> is the thickness direction of the recording layer 13 ′, and this direction is the direction of the easy magnetization axis. Thereby, the recording layer 13 ′ has perpendicular magnetic anisotropy throughout. The main factor showing the perpendicular magnetic anisotropy is considered to be an adverse effect of magnetostriction caused by a difference in thermal expansion coefficient between the recording layer 13 ′ made of CrPt ₃ and the substrate 11.

In addition to the soft magnetic layer 12, an intermediate layer may be formed between the substrate 11 and the recording layer 13 ′. The intermediate layer formed between the soft magnetic layer 12 and the recording layer 13 ′ is preferably made of, for example, SiO ₂ , SiN, or alumina and has nonmagnetic magnetic characteristics. When the recording layer 13 ′ is CrPt ₃ , it exhibits perpendicular magnetic anisotropy due to the stress generated between the substrate 11 and the recording layer 13 ′. For example, when the thickness of the soft magnetic layer 12 is about 20 nm and the thickness of the intermediate layer made of SiO ₂ is 10 nm or less, the recording layer 13 ′ made of CrPt ₃ exhibits perpendicular magnetic anisotropy due to stress with the substrate 11. It will have.

  Next, as shown in FIG. 5B, a resist film 15 is formed on the entire surface of the recording layer 13 '. The resist film 15 is made of, for example, methyl methacrylate resin (PMMA) and is formed by coating to a film thickness of about 40 nm. The resist film 15 becomes a mask pattern layer 15 ′ (see FIG. 6A) through the following steps.

  After the formation of the resist film 15, the uneven surface 30A of the stamper 30 is brought into contact with the resist film 15 as shown in FIG. At this time, the stamper 30 is heated to 120 ° C., for example, and a pressure of about 40 kN is applied to the stamper 30. The heating / pressurizing time is about 5 minutes. The stamper 30 includes a stamper body 30a and a convex portion 30b that forms an uneven surface 30A. The convex portion 30b has a pattern shape corresponding to the above-described nonmagnetic portion 13B, and the tip of the convex portion 30b is in contact with the recording layer 13 '.

  Thereafter, as shown in FIG. 6A, the resist film 15 is cured by cooling to room temperature, and then the convex portion 30 b of the stamper 30 is detached from the resist film 15. As a result, the mask pattern layer 15 ′ is formed in a state where the recording layer 13 ′ is exposed in some places according to the convex portion 30 b of the stamper 30. In the mask pattern layer 15 ', a concave / convex pattern opposite to that of the stamper 30 is transferred, and the convex portion 30b of the stamper 30 becomes a concave portion of the mask pattern layer 15'. That is, the mask pattern layer 15 'has a pattern shape corresponding to the above-described recording magnetic part 13A. In the concavo-convex pattern of the stamper 30, a portion corresponding to the recording magnetic portion 13 </ b> A that becomes a data region becomes a concave portion, and a portion corresponding to the servo region also becomes a concave portion. By transferring the concave portion to the mask pattern layer 15 ′, the convex portion remains in the mask pattern layer 15 ′. Here, the size corresponding to the recording dots is 60 nm (disc radial direction) × 40 nm (disc circumferential direction), and the actual dot pattern is approximately ¼ of the area, and the dot size is about 30 nm × 20 nm. is there. Such a pattern is formed on the entire surface of the mask pattern layer 15 'except for the servo pattern region.

Next, as shown in FIG. 6B, the recording layer 13 ′ exposed from the mask pattern layer 15 ′ is irradiated with ions. The irradiated ions are, for example, Ga ⁺ ions, and the ion dose is set to about 2 × 10 ¹⁵ ions / cm ² . The acceleration voltage at the time of ion irradiation is, for example, 22 keV. The perpendicular magnetic anisotropy constant is approximately 6 × 10 ⁶ erg / cc. Magnetic properties of the recording layer 13 'before ion irradiation, for example a coercive force Hc = 6 kOe, but was about Ms = 300 emu / cc, in Iondosu amount of 5 × 10 ⁴ ion / cm ^2, the saturation magnetization Ms of 150 emu / Decreased to cc. When a large amount of 2 × 10 ⁵ ion / cm ² was irradiated, the saturation magnetization Ms decreased to 10 emu / cc. The etching amount at this time was about 2 nm. When the X-ray diffraction of the recording layer 13 ′ having such a magnetization disappeared by about 95% was measured, no diffraction based on a Cu ₃ Au type ordered alloy was observed. In addition, due to the collapse of the ordered structure, no orientation in the <111> direction due to the polycrystals observed in the as-depo state was observed. In the portion of the recording layer 13 ′ finally irradiated with a predetermined amount of ions, the crystal structure is irregularly disturbed by Ga ⁺ ions, so that the coercive force Hc≈0 Oe and the saturation magnetization Ms = 15 emu / cc. Magnetic properties deteriorate. That is, the portion irradiated with ions in the recording layer 13 ′ becomes the nonmagnetic portion 13B, while the portion escaped from the ion irradiation by the mask pattern layer 15 ′ becomes the recording magnetic portion 13A, and these recording magnetic portion 13A and nonmagnetic portion The recording layer 13 including 13B is formed. Note that the etching amount of the mask pattern layer 15 ′ by ion irradiation is about 20 nm, and the etching amount of the recording layer 13 ′ exposed from the mask pattern layer 15 ′ is 2 nm.

Thereafter, as shown in FIG. 6C, the mask pattern layer 15 ′ is removed from the recording layer 13 by, for example, ashing using oxygen plasma, and then, for example, diamond is formed on the surface of the recording layer 13 by sputtering. A like carbon protective film 14 is formed. The O ₂ gas pressure during ashing with oxygen plasma is about 1 Pa, and the input power during ashing is about 500 W. Such ashing is performed for about 30 seconds. On the surface of the recording layer 13 formed substantially flat in this manner, a protective film 14 such as a DLC protective film and a lubricant are applied to about 3 nm. The protective film 14 and the lubricant serve to suppress wear due to rubbing with the magnetic head H. Thereby, the mask pattern layer 15 ′ is completely removed, and a finished product of the magnetic disk X as shown in FIG. 3 is obtained.

  FIG. 9 is an explanatory diagram for explaining the magnetic characteristics immediately after the recording layer 13 'is formed. As shown in FIG. 6A, when the crystal structure of the recording layer 13 ′ in the as-depo state is evaluated by the X-ray diffraction method (θ-2θ scan), it is generally oriented in the crystal plane {111} direction. it is conceivable that. When X-ray diffraction was measured in such a recording layer 13 '(φ-2θx scan), diffraction corresponding to the ordered alloy could not be observed. On the other hand, in the recording layer 13 that had been subjected to the heat treatment, when X-ray diffraction was measured by φ-2θx scan, a measurement result indicating the degree of crystal order as shown in FIG. That is, as shown in FIG. 5B, since the diffraction peak intensities are observed in the directions of the crystal planes {110} and {220}, it is considered that they are oriented in these directions. Thereby, it is considered that the recording layer 13 ′ is an almost complete ordered alloy.

FIG. 10 is an explanatory diagram for explaining magnetic characteristics by ion irradiation. The magnetic characteristics of the recording layer before ion irradiation are about Hc = 6 kOe, Ms = 300 emu / cc, and the perpendicular magnetic anisotropy constant is about 6 × 10 ⁶ erg / cc. The acceleration voltage at the time of ion irradiation is, for example, 30 keV. By irradiating such a recording layer with Ga ⁺ ions, a measurement result as shown in the figure was obtained. Thereby, by irradiating with ions, the coercive force Hc and saturation magnetization Ms of the recording layer were almost zero, and the recording layer could be almost completely demagnetized.

  Therefore, according to the manufacturing method of the present embodiment, the nonmagnetic portion 13B having almost no magnetization can be formed in the recording layer 13 by ion irradiation. It can be easily obtained without processing.

  In addition, according to the manufacturing method of the present embodiment, even if the entire surface of the recording layer 13 is irradiated with ions, the mask pattern layer 15 ′ allows ions to reach only a part of the recording layer 13, There is no need to squeeze ions for irradiation. Therefore, there is no need to form a fine ion beam as in the prior art, and there is an advantage that mass productivity is greatly improved by forming the mask pattern layer 15 ′ by imprinting using the stamper 30.

  The present invention is not limited to the above embodiment.

In addition, an ordered alloy of NiAs type may be used for the recording layer. The NiAs-type ordered alloy can have an easy axis of magnetization in the direction perpendicular to the film surface by using MnBi as a representative material and hexagonal C-axis orientation. A recording layer made of MnBi generally corresponds to a structure in which Mn and Bi are alternately stacked. The perpendicular magnetic anisotropy shows a large value of 11 × 10 ⁶ erg / cc. Such a layer of MnBi can be formed into an ordered alloy by, for example, alternately depositing Mn and Bi on a glass substrate with a substantially equivalent film thickness and then performing a heat treatment at about 350 ° C. for about 8 hours. When such an ordered alloy is irradiated with ions, the ordering is disturbed and the magnetic properties are greatly deteriorated. Thereby, even when a NiAs type ordered alloy made of, for example, MnBi is applied to the recording layer, the ordered and irregular portions can be formed in the recording layer by ion irradiation / non-irradiation.

  During manufacturing, a layer for protecting the recording layer from oxidation and ion irradiation may be provided between the surface of the recording layer and the mask pattern layer (surface portion of the recording layer covered with the mask pattern).

  For example, the film thickness and the forming method of the recording layer can be appropriately changed within the scope described in each claim.

It is an internal structure figure which shows one Embodiment of the magnetic recording / reproducing apparatus based on this invention. FIG. 2 is a partial perspective view of a magnetic disk provided in the magnetic recording / reproducing apparatus of FIG. 1. FIG. 3 is a partially enlarged sectional view of the magnetic disk in FIG. 2. FIG. 3 is an explanatory diagram for explaining a reproduction signal obtained from the magnetic disk of FIG. 2. FIG. 3 is a process diagram of a method for manufacturing the magnetic disk shown in FIG. 2. FIG. 4 is a process diagram following FIG. 3. It is explanatory drawing of the formation method of a recording layer. It is a schematic diagram of the crystal structure of a recording layer. It is explanatory drawing for demonstrating the magnetic characteristic immediately after recording layer formation. It is explanatory drawing for demonstrating the magnetic characteristic by ion irradiation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Substrate 12 Soft magnetic layer 13, 13 'Recording layer 13c' Cr layer 13p 'Pt layer 14 Protective film 15' Mask pattern layer

Claims (10)

In the recording layer formed on the substrate, it has a recording magnetic part capable of magnetically recording information and a nonmagnetic part incapable of magnetic recording,
The magnetic recording medium is characterized in that the recording magnetic part is made of a Cu ₃ Au type ordered alloy, and the non-magnetic part is made of a disordered alloy. 2. The magnetic recording medium according to claim 1, wherein the Cu ₃ Au type ordered alloy in the recording magnetic part is composed of Cr as a main component corresponding to Au and Pt as a main component corresponding to Cu. _3. The magnetic recording medium according to claim 1, wherein the Cu ₃ Au type ordered alloy has a <111> crystal axis or a <100> crystal axis in a thickness direction of the recording layer. The magnetic recording medium according to claim 1, wherein the Cu ₃ Au type ordered alloy has an easy axis of magnetization in a thickness direction of the recording layer. The magnetic recording medium according to claim 4, wherein the Cu ₃ Au type ordered alloy has an easy axis of magnetization in a thickness direction of the recording layer due to a magnetostrictive effect. In the recording layer formed on the substrate, it has a recording magnetic part capable of magnetically recording information and a nonmagnetic part incapable of magnetic recording,
The magnetic recording medium, wherein the recording magnetic part is made of a NiAs type ordered alloy, and the nonmagnetic part is made of a disordered alloy. A magnetic recording medium according to any one of claims 1 to 6,
A magnetic head for recording and reproducing information with respect to the magnetic recording medium;
A motor for rotating the magnetic recording medium;
A head moving mechanism for moving the magnetic head on the magnetic recording medium;
A magnetic recording / reproducing apparatus comprising: Forming a recording layer made of CrPt ₃ on a substrate;
Forming a mask pattern layer on the surface of the recording layer;
Irradiating each part of the recording layer exposed from the mask pattern layer with ions;
A method for manufacturing a magnetic recording medium, comprising:   The method for manufacturing a magnetic recording medium according to claim 8, further comprising a step of heating after depositing Cr and Pt on the substrate.   The method for manufacturing a magnetic recording medium according to claim 9, wherein the recording layer is formed by performing heat treatment after alternately laminating Cr layers and Pt layers on the substrate.

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