JPH0624053B2 - Magnetic recording method - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording method, and more particularly to a magnetic recording method using a magnetic recording medium having a continuous thin film type magnetic layer by a so-called oblique evaporation method.

Prior art and its problems Active development of a magnetic recording medium for video, audio, etc. having a continuous thin film type magnetic layer on a long substrate due to its compactness when wound into a tape and wound. Has been done.

As a magnetic thin film layer of such a metal thin film type medium, vapor deposition of Co, Co—Ni or the like formed by a so-called oblique vapor deposition method, which is characteristically performed by vapor deposition at a predetermined inclination angle with respect to the normal line of the substrate. Membranes are preferred.

Since the characteristics of the medium are largely deteriorated due to spacing loss, it is necessary to make the surface of the medium as smooth as possible.

However, if the surface is made too flat, friction will increase, which will hinder the head touch and the running surface.

By the way, in the metal thin film type medium, the magnetic layer is 0.05 to
Since it is as thin as 0.5 μm, the surface property of the medium depends on the surface property of the substrate.

For this reason, it has been proposed to provide comparatively smooth wrinkle-shaped or earth-shaped protrusions on the substrate surface (JP-A-53-116115, etc.).

Further, in JP-A-58-68227 and JP-A-58-100221, fine particles are arranged on the surface of a substrate so that they can be observed with an optical microscope at a magnification of 50 to 400 times, and actually measured with a stylus type surface roughness measuring device. It has been proposed to provide unevenness with a height that can be achieved.

However, even these are still insufficient in terms of physical properties such as running friction, running durability and running stability, and electromagnetic conversion characteristics.

On the other hand, Japanese Patent Publication No. 39-25246 and the like propose that a top coat layer made of an organic lubricant is provided on the surface of the ferromagnetic metal thin film layer to reduce running friction.

However, when an organic lubricant is used, adhesion of the lubricant to the head and clogging of the head occur, which poses a serious problem in practical use.

On the other hand, the ferromagnetic metal thin film layer formed by the oblique vapor deposition method is formed as an aggregate of columnar crystal grains that are inclined with respect to the normal line of the main surface of the substrate and have a longitudinal diameter extending over the entire thickness direction of the ferromagnetic metal thin film layer. To be done.

Co, Ni, etc. are present in the columnar crystal grains, and O, which is introduced as required, is present on the surface of the columnar crystal grains.
It exists by forming an oxide.

However, such a ferromagnetic metal thin film layer has a shape anisotropy in the longitudinal direction of the substrate, that is, in the traveling direction of the medium. It has the drawback of occurring.

Therefore, the present inventors previously measured the coercive force as a medium having no such input / output difference while changing the direction on a plane defined by the longitudinal direction of the substrate and the normal direction of the main surface of the substrate. (Hc max-Hc min) / Hc (0) ≦ 0.9 {where Hc max is the maximum coercive force, Hc min is the minimum coercive force, and Hc (0) is the longitudinal direction of the substrate. Represents the coercive force at. } A magnetic recording medium characterized by having the following relationship is proposed.

In this case, when the above (Hc max-Hc min) / Hc (0) is 0.6 or less, the corrosion resistance becomes extremely good, and the inventors of the present invention have also proposed this fact.

In this way, even if you control the coercive force in a given plane,
It has the drawbacks of insufficient durability and poor so-called still characteristics in the still image mode.

That is, a magnetic recording method that has low running friction, has no difference in input / output depending on whether the medium is running or not, and has very good running durability has not yet been realized.

II Object of the invention The object of the present invention is to improve the physical properties such as friction, durability running property, running stability, etc. in a magnetic recording method using a metal thin film type magnetic recording medium, and to the extent that the physical properties are not hindered. A magnetic recording method that eliminates head adhesion and clogging and that does not cause any inconvenience in terms of electromagnetic conversion characteristics. To provide.

Such an object is achieved by the present invention described below.

That is, the present invention provides a magnetic recording method for recording and reproducing a magnetic recording medium having a ferromagnetic metal thin film layer containing Co as a main component on a flexible substrate by using a magnetic head. When the length is a μm, a is 0.
1 to 0.5, and the medium surface has an average of 10 ⁵ / mm ²
a Has ^two or more protrusions, and the protrusion is 30 to 300Å
Furthermore, when the coercive force of the ferromagnetic metal thin film layer is measured while changing the direction on a plane defined by the longitudinal direction of the base and the normal to the main surface of the base, (Hc max- Hc min) / Hc (0) ≦ 0.9 (where, Hc max represents the maximum value of coercive force, Hc min represents the minimum value of coercive force, and Hc (0) represents coercive force in the longitudinal direction of the substrate. } And the filling factor of the ferromagnetic metal thin film layer is 0.7 or more.

III Specific Structure of the Invention Hereinafter, the specific structure of the present invention will be described in detail.

The magnetic recording medium used in the present invention has a ferromagnetic metal thin film layer on a substrate.

The ferromagnetic metal thin film layer in the present invention is made of Co, Co-N.
i, Co-Cr, Co-Ti, Co-Mo, Co-V,
Co-W, Co-Re, Co-Ru, Co-Mn, Co
Various known compositions such as —Fe and Fe may be used, and vapor deposition, ion plating and the like can be used as the forming method.

However, the effect of the present invention is greatest when the magnetic layer has a composition containing Co as a main component and optionally 1 to 3 of Ni, Cr, and O contained therein.

That is, it may be composed of Co alone or may be composed of Co and Ni.

When Co + Ni, the weight ratio of Co / Ni is 1.5.
The above is preferable.

Further, O may be contained in addition to Co or Co + Ni. When O is contained, more preferable results can be obtained in terms of changes in electromagnetic conversion characteristics over time and running durability.

In such a case, the atomic ratio of O / Co (when Ni is not included) or O / (Co + Ni) is preferably 0.5 or less, and particularly preferably 0.1 to 0.45.

On the other hand, in the ferromagnetic metal thin film layer, Co, Co + Ni, C
When Cr is contained in addition to o + O or Co + Ni + O, even more preferable results are obtained.

This is because the electromagnetic conversion characteristics are improved, the output and the S / N ratio are improved, and the film strength is further improved.

In such a case, Cr / Co (when Ni is not included)
Alternatively, the weight ratio of Cr / (Co + Ni) is preferably 0.1 or less, and particularly preferably 0.001 to 0.1.

Then, a more preferable result is obtained when the weight ratio of Cr / Co or Cr / (Co + Ni) is 0.005 to 0.05.

In such a ferromagnetic metal thin film layer, other trace components, especially transition elements such as Fe, Mn, V, Z
r, Nb, Ta, Ti, Zn, Mo, W, Cu, etc. may be contained.

Such a ferromagnetic metal thin film layer usually has a thickness of 0.05-0.
The thickness is 5 μm, more preferably 0.07 to 0.3 μm.

Generally, such a ferromagnetic metal thin film layer is preferably composed of an aggregate of columnar crystal grains inclined with respect to the normal to the main surface of the substrate.

In such a case, the columnar crystal grains are preferably inclined at an angle of 30 ° or more with respect to the normal line of the main surface of the base.

Each columnar crystal grain has a length over the entire thickness direction on the ferromagnetic metal thin film side, and its minor axis is about 50 to 500Å.

The inclination angle of the columnar crystal grains with respect to the normal line of the main body surface of the substrate side is preferably larger than the inclination angle of the columnar crystal grain with respect to the normal line of the main surface of the substrate body on the opposite side.

Co, Ni, Cr, etc. are present in the crystal grains, and O is mainly present on the surface of each columnar crystal grain.

Under such a premise, when the coercive force is measured while changing the direction on a plane defined by the longitudinal direction of the base body and the normal direction of the main surface of the base body, Hc max, Hc min, and Hc (0) Must be (Hc max-Hc min) / Hc (0) ≦ 0.9.

If this value exceeds 0.9, a large input / output difference of 2 dB or more will occur when the traveling direction of the medium is changed, which is not practical.

When this value is 0.6 or less, the input / output difference with respect to the forward / reverse traveling is extremely small.

On the other hand, if this value exceeds 0.6, the corrosion resistance is critically reduced, and it cannot be practically used.

When this value is 0.4 or less, the input / output difference with respect to the forward and reverse running is extremely small, and the corrosion resistance is extremely high.

Furthermore, the filling factor of the ferromagnetic metal thin film layer must be 0.7 or more.

In this case, the filling factor is ρ, where ρ is the average of the ferromagnetic metal thin film layers and ρ _B is the true density of the components of the ferromagnetic metal thin film layers.
/ Ρ _B

The average density ρ is the actually measured average density of the entire ferromagnetic metal thin film layer.

Further, the true density ρ _B is the bulk density of a homogeneous ingot of an alloy having a composition corresponding to the components of the ferromagnetic metal thin film layer.

Then, in order to measure ρ / ρ _B , first, the weight and volume of the ferromagnetic metal thin film layer are actually measured to measure ρ.

In this case, the weight is obtained by drying a sample having a constant area and the base used, weighing the sample, and calculating the weight from the difference.

Further, the thickness of the ferromagnetic metal thin film layer in calculating the volume may be obtained from a step gauge, a film thickness meter, an electron micrograph or the like.

Dividing this ρ by ρ _B directly measured from the bulk alloy ingot gives ρ / ρ _B.

Alternatively, the ferromagnetic metal thin film layer is subjected to fluorescent X-ray analysis, Auger spectroscopic analysis, ESCA, etc. to measure the number of counts of the component elements.

In this case, the ferromagnetic metal thin film layer formed by the oblique deposition method in particular is
It has a density gradient in the thickness direction, and the count number of fluorescent X-rays or the like is performed while etching is performed by an etching means of a dry process such as ion milling, and the count number is averaged. Then, even if this count number (average count number) is divided by the count number of the reference ingot, ρ
/ Ρ _B is calculated.

When ρ / ρ _B calculated in this way is 0.7 or more, running durability is reduced and the still durability time is shortened.

In this case, if ρ / ρ _B is 0.75 or more, particularly 0.8 or more, more preferable results can be obtained.

It is preferable that such ρ / ρ _B has a gradient in the thickness direction of the ferromagnetic metal thin film layer.

That is, by changing the deposition conditions, the distribution of the density of the ferromagnetic metal thin film layer in the thickness direction changes, which also causes a difference in running durability.

In this case, it is preferable that ρ / ρ _B or the average density of the portion of the ferromagnetic metal thin film layer on the substrate side is larger than ρ / ρ _B or the average density of the portion on the side opposite to the substrate.

In this case, when the ferromagnetic metal thin film layer is divided into three equal parts in the thickness direction, ρ or ρ / ρ _{B of} a portion of 1/3 from the side opposite to the base body.
Is 1. of ρ or ρ / ρ _B of a portion of 1/3 from the substrate side.
It is preferably 5 times or more, preferably 1.5 to 3 times, more preferably 1.5 to 2.5 times.

At this time, the running durability is further improved.

If it is larger than 3 times, the head touch becomes worse and the output varies.

The average density of each part in this case is, for example, ESC.
It may be obtained from the characteristic X-ray intensity of the constituent components such as A and the etching time with Ar or the like.

If desired, various top coats may be formed on the surface of such a ferromagnetic metal thin film layer.

The substrate for forming the ferromagnetic metal thin film layer is not particularly limited as long as it is a long and non-magnetic substrate, and is particularly flexible substrate, particularly made of resin such as polyester or polyimide. It is preferable.

The thickness may be various, but especially 5
It is preferably ˜20 μm.

In this case, on the back surface of the ferromagnetic metal thin film layer forming surface of the substrate,
Various known back coat layers may be formed.

On the surface of the magnetic recording medium used in the present invention having such a structure, fine protrusions are provided with a predetermined density.

The fine protrusions are 30 to 300Å, more preferably 50 to
It has a height of 250Å.

That is, the projections of the present invention can be observed with an optical microscope and can be observed with a scanning or transmission electron microscope, not with a stylus type surface roughness meter.

If the projection height exceeds 300Å and can be observed with an optical microscope, electromagnetic conversion characteristics deteriorate and running stability deteriorates.

Further, if it is less than 50Å, the improvement of physical properties is not effective.

And the density is an average of 10 ⁵ / a ² per 1 mm ² ,
More preferably, it is 2 × 10 ⁶ / a ² to 10 ⁹ / a ² .

In this case, a represents the gap length of the magnetic head used in μm unit.

And, a is 0.1 to 0.5 μm, particularly 0.1 to 0.
4 μm.

When the protrusion density is 10 ⁵ / a ² pieces / mm ² , more preferably less than 2 × 10 ⁶ / a ² pieces / mm ² , noise increases, still characteristics deteriorate, and head clogging occurs frequently. It causes a decrease in power consumption and cannot be put to practical use.

On the other hand, if it exceeds 10 ⁹ / a ² / mm ² , the effect on the physical properties will be reduced.

In order to provide such protrusions, it is usually sufficient to dispose fine particles on the substrate.

The particle size may be 30 to 300 Å, especially 50 to 250 Å, whereby fine protrusions corresponding to the particle size are formed.

The fine particles used are those generally known as colloidal particles, for example, SiO ₂ (colloidal silica), Al ₂ O ₃ (alumina sol), MgO, Ti.
O ₂ , ZnO, Fe ₂ O ₃ , zirconia, CdO, Ni
O, CaWO ₄ , CaCO ₃ , BaCO ₃ , CoC
O ₃ , BaTiO ₃ , Ti (titanium black), Au,
Ag, Cu, Ni, Fe, various hydrosols, resin particles and the like can be used. In this case, it is particularly preferable to use an inorganic substance.

Such fine particles may be used as a coating solution using various solvents, which may be coated on a substrate and dried, or a coating solution to which a resin component such as various aqueous emulsions is added may be coated and dried. Good.

In some cases, the projections may be provided by adding fine particles to the top coat layer instead of disposing the coating liquid on the substrate.

Further, when a resin component is used, it is possible to provide a gentle protrusion by superposing on the fine protrusion based on these fine particles, but it is not usually necessary to do so.

If necessary, various known underlayers may be interposed between the substrate and the ferromagnetic metal thin film layer.

If necessary, the ferromagnetic metal thin film layer may be divided into a plurality of layers, and the non-ferromagnetic metal thin film layer may be interposed therebetween.

In the present invention, the magnetic layer may be formed by electrolytic vapor deposition, ion plating, plating or the like, but it is preferably formed by a so-called oblique vapor deposition method.

In this case, the minimum value of the incident angle of the vapor deposition substance with respect to the normal to the substrate is preferably 20 ° or more.

When the incident angle is less than 20 °, the electromagnetic conversion characteristics deteriorate.

Usually, during vapor deposition, a cylindrical can for vapor deposition is used, and a vapor deposition mask is interposed therebetween so that the incident angle is 90 to 20 ° with respect to the normal to the main surface of the substrate. It is preferable to gradually reduce the incident angle on the film.

In such a case, in order to have the above-mentioned angular dependence of the coercive force, for example, a plurality of hearths or crucibles are arranged in a direction perpendicular to the feeding direction of the base body, that is, in the width direction of the base body. There are methods such as changing the evaporation rate.

Further, in order to make ρ / ρ _B and its distribution have the above values, there are methods such as changing the evaporation rate in the width direction of the substrate and slightly lowering the minimum incident angle during vapor deposition as described above. is there.

Such condition values can be easily obtained from experiments.

Incidentally, the deposition atmosphere, as usual by argon, helium, an inert atmosphere such as vacuum, and 10 ^-5 × 10 ⁰ Pa pressure of about, also deposition distance, the substrate transport direction, the can and the structure of the mask, arranged Etc. may be the same as known conditions.

However, it is preferable that oxygen is contained in the vapor deposition atmosphere to improve electromagnetic conversion characteristics and corrosion resistance.

Oxygen can be introduced into the ferromagnetic metal thin film layer by various methods for arbitrary magnetism during vapor deposition.

Then, various oxidation treatments can be performed even after the ferromagnetic metal thin film layer is formed.

Further, if a heat treatment is performed after forming the ferromagnetic metal thin film layer, more preferable results are obtained.

On the other hand, various magnetic heads can be used.

In this case, as the magnetic head, it is preferable that at least the end surface of the gap portion is made of a magnetic metal material.

In this case, the entire core can be formed of a metal ferromagnetic material, and if necessary, a part of the core including the end face of the gap can be formed of a metal ferromagnetic material.

In FIG. 1, for example, metallic half ferromagnetic bodies 31 and 32 having a thickness of about 1 to 5 μm are deposited on the end surfaces of the gaps of the core halves 21 and 22 made of a ferromagnetic material such as ferrite by sputtering or the like, and the glass Core half 2 through gap 4 of quality etc.
An example is shown in which the magnetic head 1 is configured by associating 1 and 22.

As a result, extremely good electromagnetic conversion characteristics can be obtained, the running is good, and head adhesion and head clogging are good.

The shape, structure, etc. may be known.

However, as described above, the gap length a is usually 0.1 to
0.5 μm, particularly 0.1 to 0.4 μm, and the track width is usually 10 to 50 μm, especially 10 to 20 μm.

Various ferromagnetic materials can be used, and any of amorphous magnetic metals, sendust, hard permalloy, thin films such as permalloy, and thin plates can be used.

However, among these, the amorphous magnetic alloy containing Co as a main component has particularly small head clogging or adhesion and good electromagnetic conversion characteristics.

As such an amorphous magnetic alloy, Co70 to 95 at
%, Zr, Nb, Ta, Hf,
Rare earth elements, Si, B, P, C, Al, etc., especially those containing 5 to 20 at% of Zr and / or Nb are preferable.

Alternatively, Co of 65 to 85 at% and Si and / or B of 15 to 35 at% as a vitrifying element are also preferable. In this case, Fe of 10 at% or less, 2
5 at% or less Ni, total 20 at% or less Cr, Ti, R
One or more of u, W, Mo, Ti, Mn and the like may be contained.

These amorphous magnetic alloys are formed as core halves or gaps by using sputtering or rapid quenching.

Recording and reproduction on the above-mentioned medium using such a magnetic head may be performed according to a known video recording system such as a so-called VHS system, beta system, 8 mm video system, U standard system.

IV Specific Actions and Effects of the Invention The magnetic recording method of the present invention is useful when used as a medium for video, audio, computer and the like.

According to the present invention, running durability is extremely high and still characteristics are very good.

Further, the input / output difference due to the forward and reverse of the traveling direction of the medium becomes extremely small.

Then, the corrosion resistance becomes extremely good and the characteristic deterioration is extremely small.

In addition, running friction is extremely small and stable, so running durability is further improved, running friction does not increase even after running many times, repetitive recording and playback times are dramatically improved, and still characteristics are dramatically improved. To do.

It also has high running stability and exhibits extremely high stability under a wide range of conditions from high temperature and high humidity to low temperature and low humidity.

Furthermore, the reproduction output based on the spacing loss is extremely small.

Also, there is very little noise.

Also, there is very little clogging of the head and adhesion of the head.

Such an effect is further enhanced when a metal ferromagnetic head is used.

Further, such an effect is further enhanced in high density recording with a minimum recording wavelength of less than 1 μm.

V Specific Examples of the Invention Hereinafter, specific examples of the present invention will be described in detail.

Example 1 Colloidal silica was coated on a smooth polyester film (thickness 12 μm) substantially free of fine particles, and Table 1
A substrate having micro-protrusions having the height and density shown in 1 was obtained.

Next, when the weight ratio of Co and Co / Ni is 4/1,
And an alloy having a Co / Ni / Cr weight ratio of 65/30/5, on a polyester film substrate (width 100 mm) having predetermined protrusions by an oblique vapor deposition method.
A magnetic thin film layer having a thickness of 5 μm was formed.

The substrate is continuously transported by a can, and the incident angle of the vapor deposition substance is set to 90.
Gradually decreased from. The distance between the evaporation source and the can is 200 mm.
And

Then, the vapor deposition is P _Ar = 5 × 10 ⁻³ Pa, and Was carried out in an atmosphere in which oxygen was introduced.

In this case, the molten metal area of the hearth was 25 cm ^2, and a total of 3 hearths were arranged, one at the center of the substrate and one at 2 points 20 mm away from the center of the substrate.

Of the evaporation rates from these three hearths, the evaporation rates of both hearths in the end direction of the substrate are the same, and the ratio of the evaporation rate of the hearths in the end direction and the evaporation rate of the central hearth is changed as shown in Table 1 below. went.

The minimum incident angle during vapor deposition was changed as shown in Table 1.

Then, each sample was heat-treated in air at 85 ° C. for 1 hour.

In each sample, the magnetic layer has a length over the entire thickness direction of the magnetic layer, and is composed of an aggregate of columnar crystal grains inclined with respect to the normal line of the substrate. The inclination angle was larger than that of the surface layer side portion.

The oxygen content of each sample was obtained by introducing O ₂ into the atmosphere, and O / (Co or Co + Ni) = 18 to 20
%, Without introducing O ₂ , it was about 1%.

After drying each sample and the substrate used, the weight is measured and ρ is measured, while Co / Ni and Co / Ni /
When the bulk density ρ _B of Cr was measured and ρ / ρ _B was calculated, the results shown in Table 1 below were obtained.

A value x obtained by dividing ρ / ρ _B in a portion having a film thickness of 1/3 from the surface by ρ / ρ _B in a portion having a film thickness of 1/3 from the substrate was calculated by ESCA while performing Ar etching.
The results shown in Table 1 were obtained.

Next, each sample was cut into a width of ½ inch, and a tape obtained from the central portion was produced.

The magnetic head used is that shown in FIG. 1 and has a gap length of 0.25 μm and a track length of 20 μm. In this case, the core halves 21 and 22 are made of ferrite, and the gap end faces are formed by sputtering.
It was Co0.8 Ni0.1 Zr0.1 (atomic ratio) with a thickness of μm, and the gap material was glass.

In addition, 10 ⁵ / a ² is 1.6 × 10 ⁶ .

Then, the following measurements were performed on each sample.

(1) Input / output difference in forward / reverse running direction It was mounted on a commercially available VHS type VCR and the input / output at 4.5 MHz in both running directions was measured to find the difference between the maximum values.

(2) Corrosion resistance Each sample was allowed to stand at 60 ° C. and 90% relative humidity for 7 days, and −Δφm / φm (%) per cm ² was measured.

(3) Still Durability In a still mode of a commercially available VTR device, the time (minutes) until the output attenuated to 1/2 at 20 ° C. and 60% relative humidity was measured.

(4) Running durability Each sample was subjected to a 50-pass experiment using a commercially available VTR device, and the reduction amount (dB) of the signal at 4 MHz was measured.

The results are shown in Table 1.

From the results shown in Table 1, the effects brought about by the coercive force distribution and the filling rate in the present invention are clear.

Example 2 In a sample obtained by vapor deposition of the Co / Ni alloy of Example 1 in an oxygen atmosphere, colloidal silica was applied onto a substrate,
The minute protrusions shown in Table 2 below were provided.

In the sample of the present invention, the effect of colloidal silica coating was not detected by observation with an optical microscope and measurement with a stylus type surface roughness meter, but when observed at a high magnification by a scanning electron microscope, protrusions were formed on the magnetic film. Seen, the size is
It corresponded to the size of the applied colloidal silica.

Table 2 shows the relationship between the height and density of the protrusions on the surface of the magnetic layer and the characteristics.
Shown in.

Experiments were conducted using signals having characteristics and the shortest recording wavelength of 0.7 μm.

The magnetic head used is that shown in FIG. 1 and has a gap length of 0.25 μm and a track length of 20 μm. In this case, the core halves 21 and 22 are made of ferrite, and the gap end faces are formed by sputtering.
μm thick Co0.8, Ni0.1, Zr0.1 (at%)
The gap material was glass.

Note that 10 ⁵ / a ² is 1.6 × 10 ⁶ (mm ² ) ^-1 .

A ferrite head was used as a magnetic head for comparison.

The method of measuring the characteristics is as follows.

1. Observation of protrusions SEM (scanning electron microscope) and TEM (transmission electron microscope) are used. Still characteristics Record at 5MHz and measure the still characteristics of playback output. 1
Set the OK level to 0 minutes or more.

3. Output Indicates the S / N ratio (relative value) when recording / reproducing at a center frequency of 5 MHz. Modify VHS VTR to measure up to 5MHz.

4. Noise Measure the noise (dB) at 4MHz in the playback output measurement.

5. Surface condition after endurance running test The condition of the tape surface after running for 50 passes is observed with an optical microscope.

○: No change △: Damage to magnetic surface ×: Missing magnetic layer As a result of Auger spectroscopic analysis, it was found that the surface of the magnetic layer in each of these Examples was covered with an oxide layer of 100 to 200 Å.

Sample No. 33 is of a magnetic layer containing no oxygen by vapor deposition in an atmosphere containing no oxygen.

In each of the above examples, colloidal silica was used as the inorganic fine particles, but the same result was obtained even if other substances such as alumina sol, titanium black, zirconia or various hydrosols were used.

Similar results were also obtained when a head made of Co-Fe-Ru-Cr-Si-B based amorphous was used.

It should be noted that when the head manufactured using Sendust was used, the effect was less than that in the above case.

The combination of the tape and the head according to the present invention was superior to the other combinations in terms of physical properties, the friction coefficient in each atmosphere was stable and low, and the durability and running characteristics were far superior.

[Brief description of drawings]

FIG. 1 is a front view showing an example of a magnetic head used in the present invention. 1 ... Magnetic head, 21, 22 ... Core half body, 31, 32 ... Metal ferromagnetic body, 4 ... Gap

Claims (16)

[Claims] 1. A magnetic recording method for recording and reproducing a magnetic recording medium having a ferromagnetic metal thin film layer containing Co as a main component on a flexible substrate by using a magnetic head. a is 0.
1 to 0.5, and the medium surface has an average of 10 ⁵ / mm ²
a Has ^two or more protrusions, and the protrusion is 30 to 300Å
Furthermore, when the coercive force of the ferromagnetic metal thin film layer is measured while changing the direction on a plane defined by the longitudinal direction of the base and the normal to the main surface of the base, (Hc max- Hc min) / Hc (0) ≦ 0.9 (where, Hc max represents the maximum value of coercive force, Hc min represents the minimum value of coercive force, and Hc (0) represents coercive force in the longitudinal direction of the substrate. }, And the filling factor of the ferromagnetic metal thin film layer is 0.7 or more. 2. The magnetic recording method according to claim 1, wherein at least the end surface of the gap portion of the magnetic head is made of a metal ferromagnetic material. 3. The magnetic recording method according to claim 2, wherein the metal ferromagnet is an amorphous magnetic alloy containing Co as a main component. 4. The magnetic recording method according to any one of claims 1 to 3, wherein (Hc max-Hc min) / Hc (0) ≦ 0.6. 5. The magnetic recording method according to claim 1, wherein the filling rate is 0.75 or more. 6. The ferromagnetic metal thin film layer is Co or Co
6. The magnetic recording method according to any one of claims 1 to 5, which contains 1 to 3 of Ni, Cr and O as main components. 7. A ferromagnetic metal thin film layer containing Ni, Co /
The magnetic recording method according to any one of claims 1 to 6, wherein the weight ratio of Ni is 1.5 or more. 8. The ferromagnetic metal thin film layer contains Cr, and Cr /
The magnetic recording method according to any one of claims 1 to 7, wherein the weight ratio of (Co or Co + Ni) is 0.1 or less. 9. The ferromagnetic metal thin film layer contains O, and O / (C
9. The magnetic recording method according to any one of claims 1 to 8, wherein the atomic ratio of o or Co + Ni) is 0.5 or less. 10. The ferromagnetic metal thin film layer has a thickness of 0.05 to
The magnetic recording method according to any one of claims 1 to 9, which has a thickness of 0.5 μm. 11. The magnetic recording according to any one of claims 1 to 10, wherein the ferromagnetic metal thin film layer is composed of an aggregate of columnar crystal grains inclined with respect to a normal line to the main surface of the substrate. Method. 12. A tilt angle of a columnar crystal grain on a substrate side with respect to a normal line of a substrate main surface is larger than a tilt angle of a columnar crystal grain on a side opposite to a substrate with respect to a normal line of a substrate main surface. 12. The magnetic recording method according to any one of 1 to 11 in the range. 13. The magnetic recording method according to claim 1, wherein the average density of the portion of the ferromagnetic metal thin film layer on the side opposite to the substrate is higher than the average density of the portion on the substrate side. . 14. When the ferromagnetic metal thin film layer is divided into three equal parts in the thickness direction, the average density of the 1/3 portion on the side opposite to the substrate is 1.5 or more of the average density of 1/3 on the substrate side. 14. The magnetic recording method according to claim 13, wherein 15. A flexible substrate made of a polymer, fine particles having a diameter of 30 to 300Å are arranged on the substrate, and a ferromagnetic metal thin film layer is provided thereon. 15. The magnetic recording method according to any one of 1 to 14 in the range. 16. The magnetic recording method according to any one of claims 1 to 15, wherein the ferromagnetic metal thin film layer has a ferromagnetic metal oxide layer on its surface.