JP2561455B2 - Magnetic recording / reproducing device - Google Patents

Description

The present invention relates to a perpendicular magnetic recording type magnetic recording medium using barium ferrite magnetic powder as a magnetic powder, and a signal recording or sliding contact with a magnetic layer thereof. A magnetic recording / reproducing apparatus including a ring-type magnetic head for reproducing,
More specifically, the present invention relates to the magnetic recording / reproducing apparatus which can perform high density recording favorably and can obtain high output.

[Conventional technology]

Generally, a magnetic recording medium is used in which acicular magnetic powder having magnetic anisotropy in the acicular direction in the magnetic layer is oriented in the longitudinal direction of the magnetic layer. In the case of utilizing the magnetization component in the direction, there is a limit to the improvement of the recording density, and as the signal recording density is increased, the demagnetizing field in the magnetic recording medium is increased to cause the decay and rotation of the residual magnetization. It becomes difficult to detect the signal.

Therefore, as the recording density becomes higher, the influence of the demagnetizing field becomes smaller, and the perpendicular magnetic recording method, which enables good high-density recording, has attracted attention. Although it has been studied to utilize the magnetization component of, the ferromagnetic metal thin film layer made of this type of Co-Cr alloy has insufficient mechanical strength and poor flexibility. However, sufficient durability was not obtained, and it was difficult to realize a stable head touch. Therefore, in order to solve such a problem, in recent years, a hexagonal plate-shaped barium ferrite magnetic powder having a plate-like magnetic anisotropy in a direction perpendicular to the plate surface is used, and the plate surface is parallel to the magnetic layer surface. Attempts have been made to utilize the magnetization component in the perpendicular direction by orienting it.

[Problems to be solved by the invention]

However, in the method of using the hexagonal plate-shaped barium ferrite magnetic powder, since it has excellent mechanical strength and flexibility, it is possible to realize a stable head touch with good durability, but the saturation magnetization of the barium ferrite magnetic powder is Due to its small size and the fact that this type of magnetic powder cannot sufficiently improve the packing density, the average magnetization of the magnetic layer is small, and as a result, even the lower layer of the magnetic layer is sufficient to obtain a large reproduction output. It is necessary to make a record. However, when the conventionally used Mn-Zn ferrite ring type head was used for this, recording could not be sufficiently performed up to the lower layer of the magnetic layer, resulting in insufficient output.

[Means for solving problems]

The present invention has been made as a result of various studies in view of the above circumstances. At least in the vicinity of the working gap of the ring-type magnetic head, the amorphous magnetic material has a high saturation magnetic flux density of 6000 gauss or higher and a high magnetic permeability. Made of alloy,
The length of the working gap in the running direction of the magnetic recording medium is 0.15 to 0.
By using a ring type magnetic head in the range of 4 μm, the ring type magnetic head is used to record and reproduce a magnetic recording medium for perpendicular magnetic recording in which barium ferrite magnetic powder is contained in the magnetic layer. The lower layer is sufficiently recorded to increase the output at the time of recording / reproducing so that high density recording can be sufficiently performed.

The ring type magnetic head used in the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of a ring type magnetic head according to the present invention. The ring type magnetic head A is a core half 1
Excitation coils 3 and 4 are wound around and 2, respectively.

Reference numerals 5 and 6 denote laminated magnetic films deposited on the working gap 7 side of the core halves 1 and 2, respectively. These laminated magnetic films 5 and 6 are composed of magnetic films 5a and 6a and non-magnetic films 5b and 6b. The layers are alternately laminated. In this way, the magnetic films 5a and 6a of the laminated magnetic films 5 and 6 deposited in the vicinity of the working gap 7 of the ring type magnetic head A have the saturation magnetic flux density of 6000.
It is preferable that the magnetic flux is composed of a soft magnetic material having a high saturation magnetic flux density of Gauss or higher.
Recording and reproduction of a magnetic recording medium for perpendicular magnetic recording using barium ferrite magnetic powder using a ring-type magnetic head A having magnetic films 5a and 6a made of a magnetic material of 00 gauss or more results in high density recording. Can be performed well and high output can be obtained. On the other hand, if the magnetic films 5a and 6a are made of a magnetic material having a smaller saturation magnetic flux density than this, the magnetic core will be saturated depending on the energization amount of the magnetic head, and perpendicular magnetic recording using barium ferrite magnetic powder. High density recording cannot be satisfactorily performed on the magnetic recording medium for use and high output cannot be obtained.

An amorphous alloy having a high saturation magnetic flux density and a high magnetic permeability is used as a material for the magnetic films 5a and 6a of the laminated magnetic films 5 and 6, and a non-magnetic alloy having a high saturation magnetic flux density and a high magnetic permeability is used. Magnetic films 5a and 6a made of amorphous alloy
Is formed by a method such as sputtering or vacuum deposition. As the amorphous alloy having a high saturation magnetic flux density and a high magnetic permeability, one or more elements selected from the group of iron, nickel and cobalt, phosphorus, carbon and boron,
An alloy consisting of one or more elements selected from the group of silicon, or with these as the main components, aluminum, germanium, beryllium, tin, molybdenum, indium, tungsten, titanium, manganese, chromium,
An alloy containing an element such as zirconium, hafnium or niobium, or an alloy containing cobalt or zirconium as a main component and containing the above-mentioned additional element is preferably used.

Thus, in the case where the vicinity of the operating gap of the ring type magnetic head is constituted by the laminated magnetic films 5 and 6 of two or more layers in which the magnetic films 5a and 6a and the non-magnetic films 5b and 6b are alternately laminated, Compared to the one composed of a single layer of iron-aluminum-silicon alloy (Sendust), there is less magnetic loss due to the generation of eddy currents, so the output is
It has excellent characteristics such as recording density D _{50 of} 50%, and is especially prized as a magnetic head for high density recording.

As the material of the non-magnetic films 5b and 6b of the laminated magnetic films 5 and 6, for example, a non-magnetic material such as silicon dioxide or glass is used.

As the material of the core halves 1 and 2, for example, a magnetic material having a high magnetic permeability such as manganese-zinc ferrite or nickel-zinc ferrite, or a non-magnetic material such as ceramic or zinc ferrite is used.

The gap length of the working gap 7 of the ring-type magnetic head thus formed is preferably regulated in the range of 0.15 to 0.4 μm. When it is shorter than 0.15 μm, the head output becomes low, while the gap length becomes 0.4. If it is longer than μm, the D ₅₀ value decreases and high density recording cannot be performed well.

FIG. 2 shows another example of the ring type magnetic head according to the present invention. In this ring type magnetic head B, a ribbon 10 having a high saturation magnetic flux density is provided with a pair of core halves 11 respectively.
And 21 sandwiched between and supported by each pair of core halves 11 and 21.
The exciting coils 31 and 41 are wound around the coil.

The ribbon 10 is formed by a super-quenching method using a soft magnetic material having a high saturation magnetic flux density. Like the magnetic films 5a and 6a of the laminated magnetic films 5 and 6, the ribbon 10 has a saturation magnetic flux density of 6000.
It is composed of a soft magnetic material having a high saturation magnetic flux density of Gauss or higher, and an amorphous alloy having the same high saturation magnetic flux density and high magnetic permeability is also used as the material. Also, the core half 11 and
The material of 21 and the working gap length 71 are also the same as those of the ring type magnetic head, and the same effects as described above can be obtained, and high density recording is favorably performed and high output is obtained. The vicinity of the working gap of such a ring-type magnetic head is
In addition to the laminated magnetic films 5 and 6 and the ribbon 10 formed by the ultraquenching method, an artificial lattice film including a ferromagnetic metal thin film layer may be used.

Further, the magnetic recording medium for perpendicular magnetic recording in the present invention comprises a hexagonal plate-shaped barium ferrite magnetic powder having a magnetic anisotropy direction perpendicular to the plate surface, a binder resin,
Barium ferrite in the magnetic layer is formed by mixing and dispersing with an organic solvent or the like to prepare a magnetic coating material, applying the magnetic coating material onto a substrate such as a polyester film by an arbitrary coating means such as a roll coater, and drying. Needless to say, when the magnetic powder is subjected to orientation treatment,
Even if the alignment treatment is not carried out, the plate surface is oriented parallel to the magnetic layer surface by the mechanical shearing force at the time of application, so that the perpendicular magnetization component is utilized well and the perpendicular magnetic recording is well performed. When the orientation treatment is not performed as described above, the vertical orientation of the barium ferrite magnetic powder in the magnetic layer is lower than when the orientation treatment is performed, but the residual magnetization in the vertical direction remains in the in-plane direction. It is sufficient if the orientation is larger than the magnetization and to some extent. The barium ferrite magnetic powder used by being contained in the magnetic layer in this way is prepared by a method of adding an alkaline aqueous solution to an aqueous solution of a metal salt containing a Ba salt and an iron salt, and then performing hydrothermal treatment, for example. , A hexagonal plate-like Ba ferrite magnetic powder represented by the composition of BaO.6Fe ₂ O ₃ , or this Ba ferrite magnetic powder
A Ba ferrite magnetic powder in which Fe is replaced by an element such as Co or Ti is preferably used. The particle size is preferably 0.5 μm or less, and if the particle size is larger than 0.5 μm, the surface smoothness of the magnetic layer is not sufficiently improved, and good high density recording cannot be performed. The coercive force is 40
It is preferable to use those having a coercive force within the range of 0 to 2000 Oersted. When the coercive force is less than 400 Oersted, high density recording cannot be performed well, and those having more than 2000 Oersted are not suitable for magnetic recording media.

Further, the coercive force of the magnetic layer of a magnetic recording medium formed using such barium ferrite magnetic powder is 400 to 2
Within the range of 000 oersteds, the residual magnetic flux density is 1000 gauss or more, and the surface roughness is 0.05 μm as the center line average roughness.
If the coercive force is too low, high-density recording cannot be satisfactorily performed, and if it exceeds 2000 oersteds, a magnetic material having a high saturation magnetic flux density of 6000 gauss or more even in the vicinity of the working gap. However, the recording magnetic field is not sufficient and the recording becomes insufficient. Also, if the residual magnetic flux density is less than 1000 gauss, a sufficient head output cannot be obtained due to the relationship with amplifier noise, and if the surface roughness is more than 0.05 μm as the center line average roughness, the S / N will decrease,
High-density recording cannot be performed satisfactorily.

The magnetic properties such as the coercive force and the residual magnetic flux density of the magnetic layer of the magnetic recording medium described above and below show values after diamagnetic field correction.

When forming a magnetic layer containing such barium ferrite magnetic powder, as the binder resin used, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral resin, fibrin resin, polyurethane resin, isocyanate compound Conventionally used binder resins such as radiation-curable resins are widely used, and as the organic solvent, toluene, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, tetrahydrofuran, ethyl acetate or other conventionally used organic solvents are used alone or Used as a mixture of two or more kinds.

[Action]

With respect to the magnetic layer of the magnetic recording medium for perpendicular magnetic recording using such barium ferrite magnetic powder, an amorphous material having a high saturation magnetic flux density and a high magnetic permeability of 6000 gauss or more at least in the vicinity of the working gap of the ring type magnetic head. The length of the working gap in the running direction of the magnetic recording medium is 0.15
When recording / reproducing with a ring type magnetic head in the range of up to 0.4 μm, the distribution of the recording magnetic field generated near the gap of this type of ring type magnetic head becomes sharp and the magnetic field strength also increases, so that the coercive force is increased. Large and relatively thick magnetic layer Magnetic field using barium ferrite magnetic powder is sufficiently suitable for saturated recording up to the lower layer to increase the reproduction output, and makes the perpendicular magnetization component of barium ferrite magnetic powder effective. By utilizing this, high density recording can be satisfactorily performed and high output can be obtained.

The combination of the ring type magnetic head of the present invention and the magnetic recording medium having a magnetic layer using barium ferrite is not limited to recording and reproduction, but only recording is performed by this combination, and reproduction is performed with a magnetic recording medium having another structure. The electromagnetic conversion characteristics are improved even when using the head.

〔Example〕

 Next, an embodiment of the present invention will be described.

Example 1 Ba ferrite magnetic powder (particle size: 0.15 μm, coercive force: 550 oersted) 450 parts by weight VAGH (vinyl chloride-vinyl acetate-vinyl alcohol copolymer manufactured by UCC, USA) 50 〃 Pandex T5201 (Dainippon Ink and Chemicals) Kogyo Co., Ltd., polyurethane resin) 30〃 Coronate L (Nippon Polyurethane Industry Co., Ltd., trifunctional low molecular weight isocyanate compound) 20〃 Carbon black 36〃 Al ₂ O ₃ powder 27〃 α-Fe ₂ O ₃ powder 18〃 2- A magnetic paint was prepared by mixing and dispersing a composition of ethylhexyl oleate 14 〃 cyclohexanone 650 〃 toluene 650 〃 in a ball mill for 15 minutes. This magnetic paint has a thickness of 75 μm
Was coated on both sides of the polyester film and calendered to form a magnetic layer having a thickness of 2.50 μm. After that, the disk was punched out to make a magnetic disk. The magnetic disk thus obtained has a saturation magnetization of 140 gauss, a vertical coercive force of 800 oersteds, an in-plane coercive force of 350 oersteds, and a vertical squareness ratio of 0.9.
3. The squareness ratio in the in-plane direction was 0.20.

On the other hand, as shown in FIG. 1, the saturation magnetic flux density is 9500 at the end on the working gap 7 side of the Mn-Zn ferrite core halves 1 and 2.
Magnetic films 5a and 6a made of Gaussian Co-Zr-Nb amorphous film,
Non-magnetic films 5b and 6b made of SiO ₂ film are 6.0μm and 0.05μm, respectively.
The magnetic films 5 and 6 are formed by laminating 10 layers with a film thickness of m by the high frequency sputtering method, and the gap length is 0.21 μm.
A ring-type magnetic head having a track width of 70 μm was manufactured, and recording / reproducing was performed on the magnetic disk with the ring-type magnetic head to examine the recording / reproducing characteristics. Graph A in FIG. 3 shows the result in relation to the reproduction output and the recording density.

Example 2 Instead of the ring type magnetic head used in Example 1, as shown in FIG.
A Co-Fe-Si-B amorphous ribbon 10 having a saturation magnetic flux density of 9000 gauss at m and a pair of core halves 11 and 21 was supported to prepare a ring type magnetic head having a gap length of 0.30 μm. Using this ring type magnetic head mounted on a button type slider, recording / reproduction of the above-mentioned magnetic disk was performed to examine the recording / reproduction characteristics. Graph A in FIG. 4 shows the result in the relationship between the reproduction output and the recording density.

Comparative Example 1 Instead of the ring type magnetic head used in Example 1, an Mn-Zn ferrite ring head having the same structure as the ring type magnetic head used in Example 1 and having the same gap length and the same track width was produced. Recording / reproduction was performed on the magnetic disk in the same manner as in Example 1 except that the recording / reproduction characteristics were examined. Graph B in FIG. 3 shows the result in the relationship between the reproduction output and the recording density.

Comparative Example 2 In place of the ring type magnetic head used in Example 2, a Ni-Zn ferrite ring head having the same structure as the ring type magnetic head used in Example 2 and having the same gap length and the same track width was produced. Recording and reproducing were performed on the magnetic disk in the same manner as in Example 2 except that the recording and reproducing characteristics were examined. Graph B in FIG. 4 shows the result in the relationship between the reproduction output and the recording density.

〔The invention's effect〕

As apparent from FIGS. 2 and 3, the magnetic recording / reproducing apparatus according to the present invention (graph A) has a conventional Mn
Compared with the one using -Zn ferrite ring head (graph B), the reproduction output is higher and the D _{50 at} which the output at 1 KBPI is reduced by half is twice or more. From this, according to the magnetic recording / reproducing apparatus of the present invention. It can be seen that high density recording can be sufficiently performed and high output can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing an example of the magnetic head according to the present invention, FIG. 2 is a schematic perspective view showing the other example, and FIG. 3 is a magnetic recording obtained in Example 1 and Comparative Example 1. FIG. 4 is a diagram showing the relationship between the reproduction output and the recording density when the magnetic disk is recorded and reproduced by the reproducing apparatus, and FIG. It is a relationship diagram of an output and a recording density. 1,2,11,21 …… Core half, 5,6 …… Multilayer magnetic film, 5a, 6a…
... Magnetic film, 5b, 6b ... Non-magnetic film, 7,71 ... Magnetic gap, 10 ... Ribbon, A, B ... Ring type magnetic head

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Osamu Inagoya 1-88 No. 1 Tora, Ibaraki City Hitachi Maxell, Ltd. (56) References JP 59-201211 (JP, A) JP 59 -127213 (JP, A) JP 60-25014 (JP, A) JP 59-168902 (JP, A) JP 60-45902 (JP, A) JP 59-129935 (JP, A) ) Actually open Sho 57-180829 (JP, U) Japanese Patent Sho 59-12758 (JP, B2)

Claims (1)

(57) [Claims] 1. A magnetic coating material containing magnetic powder is applied onto a substrate,
A magnetic recording / reproducing apparatus comprising a magnetic recording medium having a magnetic layer formed by drying, and a ring-type magnetic head for recording / reproducing a signal by slidingly contacting the magnetic layer of the magnetic recording medium. As a magnetic powder to be included in the layer,
Using barium ferrite magnetic powder having a particle size of 0.5 μm or less and a coercive force of 400 to 2000 Oersted, a high permeability having a high saturation magnetic flux density of 6000 gauss or more at least near the working gap of the ring type magnetic head. A magnetic recording / reproducing apparatus comprising an amorphous alloy having a magnetic susceptibility, wherein the length of the working gap of the ring type magnetic head in the running direction of the magnetic recording medium is in the range of 0.15 to 0.4 μm.