KR100802009B1 - Magnetism record medium using fept-b and method for manufacturing thereof - Google Patents

Abstract

A magnetism record medium using an FePt-B thin film and a method for manufacturing the same are provided to secure high coercivity and corrosion resistance of a magnetism record medium by adding Boron to an FePt alloy thin film. A magnetism record medium comprises an information recording unit for recording information, and an information storage unit for automatically storing the information recorded by the information recording unit. The information storage unit is made with an FePt-B thin film of an isotropic crystal structure formed by depositing Fe, Pt, and Born simultaneously so that the volume percent of the Boron is 33% and heat-treating at the temperature of 500~600°C.

Description

Magnetic recording medium using a thin film and method for manufacturing the same {magnetism record medium using

1 is a graph showing the coercive force change according to the amount of boron (B) added to the FePt alloy thin film and the heat treatment temperature.

Figure 2 is a graph showing the XRD result data when adding boron (B).

3 is a graph showing a change in lattice constant according to the amount of boron (B) added.

4 is a graph showing the Tetragonality value according to the addition amount of boron (B) and the heat treatment temperature.

The present invention relates to a magnetic recording medium using a FePt-B thin film and a method for manufacturing the same, and particularly, by adding B (Boron), which is a third element, to a FePt alloy thin film to help reduce the regularization temperature and to have a high coercive force. A magnetic recording medium using a FePt-B thin film and a method of manufacturing the same.

Magnetic recording occupies its place as an important memory technology that leads the information society by utilizing features such as nonvolatile, large capacity, low bit cost, and relatively high access speed.

At the moment there is no viable technology to replace the magnetic record, this situation will probably continue until this century. On the other hand, the recent rapid development of the information society requires the densification of magnetic recording, and the increase in recording surface density is about 100% per year, and the test density of 100 Gbit / inch ² or more has already been achieved. Considering the trend of magnetic recording technology, the surface recording density is expected to reach 1Tbit / inch ² within the next 10 years.

Magnetic recording media that have been used up to now have been analyzed as important features such as thin film recording material, magnetic anisotropy energy (Ku), coercive force (Hc), and nanoparticle size. In response to these technical characteristics, the recording density of magnetic recording media has grown more than 100 times in the decade since the 1990s.

As a result, the bit size recorded on the magnetic recording medium is also reduced, and miniaturization processes such as the recording bit length ranging from several micrometers to several nm have been developed. Furthermore, if the density is increased at such a face, it is expected that by 2010, the surface recording density of Tb / inch ² will be reached, and the bit size at this time will be reduced to about 40 nm x 15 nm.

At such a high recording density of Tb / inch ² , FePt-based regular alloys having higher magnetic anisotropy than CoPt and CoPt than conventional CoCr systems have attracted much attention as next generation high density recording materials.

In general, the coercive force of the material used as the magnetic recording medium for information recording is about 5 kOe or more in consideration of the stability of the magnetic recording and the capacity of the recording head, and the particle size should be small for high density recording.

However, although the particles of the media material can be produced by isolating particles of several nm or so, the thermal stability is poor, resulting in superparamagnetism, random crystal direction, and regularization temperature. Will be lowered.

By the way, FePt has high crystallite anisotropy, so it is expected that the above problems will not occur. However, in order to have a large coercive force with crystallite anisotropy in the disordered Face Centered Cubic, which has no crystallite anisotropy, In order to transform into an ordered face centered tetragonal (FCT) structure, regular heat treatment must be performed at a high temperature of 600 ° C. or higher, so it remains a big problem when applied to a device.

In general, heat treatment at 300 to 400 ° C is recommended for applications. As described above, lowering the regularization temperature and obtaining a coercive force of a predetermined size or more is an essential requirement as a magnetic recording material.

The present invention is proposed to solve the problems of the prior art as described above, by adding a third element B (Boron) to the FePt alloy thin film to help reduce the regularization temperature, FePt- which can have a high coercivity An object of the present invention is to provide a magnetic recording medium using the B thin film and a method of manufacturing the same.

In order to solve the above technical problem, the magnetic recording medium using the FePt-B thin film and the constituent means of the manufacturing method of the present invention have an information recording means for recording information and the information recording means by magnetic information recording means. A magnetic recording medium comprising information storage means to be recorded, wherein the information storage means comprises a FePt-B thin film formed by simultaneously depositing iron (Fe), platinum (Pt) and boron (B: Boron). Shall.

In addition, the content of the boron (B: Boron) is preferably 5 to 33% by volume.

On the other hand, the constituent means constituting a method of manufacturing a magnetic recording medium comprising information recording means for recording information and information storage means for recording information magnetically by the information recording means, the information storage means is boron (B: ), So that the content of 5 to 33% by volume, iron (Fe), platinum (Pt) and boron (B: Boron) by simultaneously depositing is characterized in that it is produced by forming a FePt-B thin film.

In addition, the FePt-B thin film is characterized in that it is co-deposited using an RF Magnetron Sputtering (Radio Frequency Magnetron Sputtering) device.

In addition, the FePt-B thin film is characterized in that the heat treatment in the range of 300 ℃ to 600 ℃ for 30 minutes to 2 hours in a vacuum state.

In addition, the FePt-B thin film includes the boron (B: Boron) in a content of 9% by volume to 20% by volume, and is characterized in that the heat treatment is performed in a range of 400 ° C to 600 ° C.

In addition, the FePt-B thin film is in an amorphous state in the deposited state including the boron (B: Boron) in a content of 30% by volume to 33% by volume, and is heat-treated in a range of 300 ° C to 600 ° C, and isotropic crystal structure Characterized in having a.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of a magnetic recording medium using the FePt-B thin film of the present invention made of the above-described configuration means and a method of manufacturing the same.

The present invention provides a magnetic recording medium on which a FePt-B alloy thin film is co-deposited with MgO as an underlying layer in order to assist the magnetization of the FePt alloy thin film on a silicon (Si) substrate in the vertical direction. That is, iron (Fe), platinum (Pt) and boron (B: Boron) are simultaneously deposited on the MgO to form a FePt-B thin film. The content of the boron to be deposited at the same time is preferably 5 to 33% by volume.

The present invention also provides a method of manufacturing the magnetic recording medium comprising information recording means for recording information and information storage means for magnetically recording information by the information recording means, wherein the information storage means is boron. It is manufactured by simultaneously depositing iron (Fe), platinum (Pt) and boron (B: Boron) on a substrate so that the content of (B: Boron) is 5 to 33% by volume to form a FePt-B thin film.

The magnetic recording medium of the present invention was manufactured by a simultaneous deposition method using an RF magnetron sputtering device, the initial vacuum before deposition was a high vacuum of 5 × 10 -8 Torr or less, and the purity of the sputtering gas is 99.9999. % Argon (Ar) was used.

The argon pressure during sputtering is FePt-B; 6 mtorr, MgO; It was maintained at 8 mtorr and the working power was 40W and 100W respectively. The composition of Fe and Pt is maintained at about 1: 1, and the content of B is varied from 1% to 33%, and thin films are manufactured to determine the optimal boron (B) content and the development of new materials according to the characteristics of the magnetic recording medium. Investigate.

In the present invention, a composition change of boron (B) was applied to a 2 inch diameter FePt alloy disk by adjusting the number of 5 × 5 × 1 mm boron (B) chips. The structure of all specimens was made of MgO _20nm / FePt-B _50nm / MgO _20nm , and the size was 10 × 20mm and 5 × 5mm for XRD analysis, VSM and DMSVSM (Digital Measurement System Vibrating Sample Magnetometer). Made to the size of.

After the FePt-B thin film was prepared, heat treatment was performed under vacuum (1 × 10 −6 Torr or less). The heat treatment temperature ranges from 300 ° C. to 600 ° C., and may be performed for 30 minutes to 2 hours. In the embodiment of the present invention was carried out at intervals of 50 ℃ to 300 ℃ to 600 ℃ each was performed for 1 hour heat treatment.

In the present invention, the crystal structure and orientation of the thin film were observed by an X-ray diffraction analyzer (XRD), and the magnetic properties of the thin film were measured using a VSM (Vibrating Sample Magnetometer) and DMSVSM (Digital Measurement System Vibrating Sample Magnetometer). . Then, the thickness was measured by α-step, the content of boron (B) was analyzed by WDS (Wave Dispersive Spectrometer).

Hereinafter, in order to manufacture a magnetic recording medium according to the present invention, a description will be made with reference to the accompanying drawings showing various characteristics when a thin film having B added to the FePt alloy and the thickness of the thin film is changed.

1 is a graph showing the change in coercive force according to annealing temperature after dividing boron (B) from 5% by volume to 33% by volume of FePt and dividing it into a structure of MgO _20nm / FePt-B _50nm / MgO _20nm .

As shown in FIG. 1, a value of 5 kOe or more, which indicates that the ordering progresses as the boron (B) is added, appears mostly from around 400 ° C. In addition, it showed the highest coercive force in the alloy thin film added with boron (B) 10% by volume and 15% by volume at 400 ° C, and the lowest coercive force in the thin film added with 25% by volume and 33% by volume.

Specifically, when the FePt-B thin film to which the content of 9% by volume to 20% by volume, which includes the content of 10% by volume and 15% by volume of boron (B), is subjected to heat treatment within a range of 400 ° C to 600 ° C, We can see that the coercive force is high. That is, the coercivity is also increased as the heat treatment temperature is gradually increased for the thin film to which the content of 9% to 20% by volume, which includes the 10% by volume and 15% by volume, is added by 33% of boron (B). The thin film does not show a big change.

2 is a 15% added FePt-B alloy thin film ((a)) showing the highest addition effect as shown in FIG. 1 and the lowest coercive force, so that the addition of boron (B) added 33% FePt showing the adverse effect rather -B alloy thin film ((b) picture) is heat treated at 300 ℃ to 600 ℃ at 50 ℃ intervals for 1 hour and then compares the XRD results.

As shown in FIG. 2, the two graphs show a marked difference, and among them, a peak from 350 ° C. in the case of FePt (001) peak added at 15% indicates high intensity. Particularly, when 33% is added, an amorphous phase appears in the deposited state, and has a characteristic of a new material having an isotropic (a-axis and a-axis are almost the same) structure by heat treatment. The thin film having this property is a magnetic material having excellent corrosion resistance in the case of an amorphous phase, and has a characteristic of having an appropriate coercive force after heat treatment.

FIG. 3 shows the lattice constants according to the respective compositions and the heat treatment temperatures through the XRD results of FIG. 2. In Figure 3 it can be seen that the degree of regularization and the role of boron (B) when ordering through the change of the a-axis and c-axis according to the regularization to L10 FePt. The addition of 10% and addition of 15% resulted in a significant change of the a-axis and c-axis, indicating that the FCC changed to an FCT structure. The characteristics of the new isotropic magnetic material are almost the same.

From this result, the coercive force also increases as the heat treatment temperature gradually increases for the thin film to which the boron content of 9% by volume to 20% by volume, which includes the 10% by volume and 15% by volume of boron, is added ( As shown in Figure 1), it can be seen that the ordering is made between 400 ℃ to 600 ℃. That is, since the regularization occurs in the thin film to which the boron content of 9% by volume to 20% by volume is added even at 400 ° C, it can be seen that the ordering temperature is significantly reduced than before.

On the contrary, the FePt-B thin film in the deposited state including the boron (B: Boron) in a content of 30% by volume to 33% by volume is heat-treated in a range between 300 ° C and 600 ° C, It can be seen that it has an isotropic crystal structure. Therefore, when the addition of boron (B) more than 30% by volume it can be seen that a new material is developed by the excessive addition of boron (B).

4 shows the c / a ratio through the lattice constants shown in FIG. 3 to more clearly understand the degree of lattice deformation after heat treatment. As the value is close to 1, the lattice strain is low, indicating low tetragonality, and thus, the transformation into a complete FCT structure cannot be considered. Therefore, as shown in FIG. 4, when the boron (B) 33% was added as in FIG. 3, there was almost no lattice deformation, and the largest change was achieved when 10% and 15% were added.

According to the magnetic recording medium and the manufacturing method using the FePt-B thin film of the present invention having the above-described configuration and preferred embodiment, by adding a predetermined content of B (Boron) as a third element to the FePt alloy thin film to reduce the ordering temperature It can be made, and has the effect of having high coercivity.

In detail, first, the boron (B) was deposited on FePt with 5%, 10%, 15%, and 20% of the composition deposited on the substrate, and compared with 10% and 15%. In addition, there is an effect that can produce a magnetic recording medium having a high coercivity based on the result showing the highest coercivity.

In addition, when 25% and 33% of boron (B) is added to FePt, on the contrary, the addition effect does not appear, but the coercive force is lowered, but the new isotropic magnetic material having excellent corrosion resistance and moderate coercive force is obtained.

Second, XRD results show that when 15% of boron (B) is added, the normalization proceeds from the peaks of (001), (200), and (002) from around 350 ° C before the coercive force sharply increases, reducing the regularization temperature. Can be.

Third, when boron (B) is added to FePt, the lattice constant changes rapidly in specimens added up to 15%, but when it is added above, it is found that lattice deformation is rather slowed down. There is an effect that can determine the boron content of.

Accordingly, it can be seen that when boron (B) is co-deposited on the FePt target according to the present invention, the FePt-B phase is formed and the regularization temperature is reduced by about 100 ° C. as compared with the conventional FePt. .

Claims (7)

A magnetic recording medium comprising information recording means for recording information and information storage means for magnetically recording information by the information recording means, The information storage means is deposited simultaneously so that the content of the boron (B: Boron) of iron (Fe), platinum (Pt) and boron (B: Boron) to 33% by volume, in the range of 500 ℃ to 600 ℃ A magnetic recording medium using a FePt-B thin film, which is formed by heat treatment to form an FePt-B thin film having an isotropic crystal structure. delete A method of manufacturing a magnetic recording medium comprising information recording means for recording information and information storage means for magnetically recording information by the information recording means, The information storage means is iron (Fe), platinum (Pt) and boron (B :) on a substrate using an RF magnetron sputtering device, so that the content of boron (B: Boron) is 33% by volume. Simultaneous deposition of Boron) to form an amorphous FePt-B thin film; A method of manufacturing a magnetic recording medium using a FePt-B thin film, characterized in that to form a FePt-B thin film having an isotropic crystal structure by heat treatment in the range of 500 ℃ to 600 ℃. delete delete delete delete

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