JPH02173913A - Magnetic head - Google Patents

Abstract

PURPOSE:To satisfy the resolution and the overwrite characteristic by providing a high-saturation magnetic flux density alloy thin film and a low-saturation magnetic flux density amorphous thin film on surfaces facing a gap part of cores. CONSTITUTION:A core 1 whose surface facing the gap part a low-saturation magnetic flux density amorphous thin film 5 is formed on and a core 2 whose surface facing the gap part a high-saturation magnetic flux density alloy thin film 7 is formed on are provided. In this case, the saturation magnetic flux density of the low-saturation magnetic flux density amorphous thin film is 1,500 to 3,000G, and cores 1 and 2 are joined into one body with a silicon oxide nonmagnetic part 6 between them. That is, the low-saturation magnetic flux density amorphous thin film 5 is magnetically saturated to function as a part of the gap at the time of recording and a strong magnetic flux is impressed from the high-saturation magnetic flux density alloy thin film 7 then. At the time of reproducing, the low-saturation magnetic flux density amorphous thin film 5 functions as a part of the core 1 and reproducing with a narrow gap is performed. Since the nonmagnetic part 6 is made of a silicon oxide nonmagnetic material, reaction between the nonmagnetic part and metal is not caused. Thus, the overwrite characteristic and the resolution are satisfactory and free from degradation.

Description

Detailed Description of the Invention <Field of Industrial Application> The present invention relates to a magnetic head for magnetic recording media such as floppy disks, magnetic disks, hard disks, etc., particularly to a magnetic head for both recording and reproduction. a first core on which a thin film having a saturation magnetic flux density higher than that of the core is formed on a surface facing the gap portion;
A so-called enhanced dual gap length (EDG) type magnetic head, which has at least a second core formed with a thin film having a saturation magnetic flux density lower than that of the core, and both cores are joined and integrated via a non-magnetic part. Regarding.

<Prior Art> When recording and reproducing information on a magnetic recording medium, it is preferable to use a magnetic head having a core with a wide gap during recording in order to provide a large magnetic flux, and to increase resolution during reproduction. , it is preferred to use a magnetic head with a narrow gap core.

However, when recording and reproducing are performed using a single magnetic head for both recording and reproducing purposes, the above requirements cannot be met because the gap length is fixed.

In order to eliminate such drawbacks, Japanese Patent Application Laid-Open No. 60-874
No. 11 proposes a magnetic head as shown in FIG.

The magnetic head shown in FIG. 2 has an oxide-based soft magnetic thin film 15 made of garnet or the like having a lower saturation magnetic flux density than that of the core formed on the surface facing the gap of the core 1, and a thin oxide-based soft magnetic film 15 made of garnet or the like having a lower saturation magnetic flux density than the core. It also has a high saturation magnetic flux density magnetic layer 17 made of permalloy or the like having a high saturation magnetic flux density. This magnetic head is a so-called enhanced dual gap length (EDG) type magnetic head.

In this magnetic head, as a result of the magnetic saturation of the oxide-based soft magnetic thin film 15 with a low saturation magnetic flux density during recording, the oxide-based soft magnetic thin film 15 and the non-6 competitive area 16 form a sloppy gap (because of the wide gap). In addition, since strong magnetic flux can be applied to the magnetic recording medium from the high saturation magnetic flux density magnetic layer 17, effective recording can be performed on a medium with a high coercive force, and during reproduction, the magnetic recording medium Since the leakage magnetic flux from the core 1 is minute, the oxide-based soft magnetic thin film 15 functions as a part of the core 1, making it possible to perform reproduction using a narrow gap and achieving high resolution.

In order to satisfy the above-mentioned performance, the thin film with a low saturation magnetic flux density provided on the opposing surface of the gap must have a saturation magnetic flux density lower than that of ferrite, a large initial permeability, and a small coercive force. It won't happen.

<Problem to be solved by the invention> However, with oxide-based soft magnetic materials, it is not possible to obtain low saturation magnetic flux density, high initial permeability, and low coercive force, so sufficient recording and reproducing characteristics cannot be obtained. Variations in characteristics also occur. In addition, since oxide-based soft magnetic materials generate magnetization by adopting a specific crystal structure, it is necessary to strictly narrow down the film-forming conditions, and further heat treatment is often required, which poses manufacturing difficulties. .

Note that various crystalline metals are also known as soft magnetic materials with low saturation magnetic flux density, but even if these are used in the form of thin films, sufficient recording and reproducing characteristics cannot be obtained as with the oxide-based soft magnetic materials. do not have.

In addition, conventionally, high-strength glass has been used for the non-magnetic part 16, but since glass easily reacts with metal, the magnetic properties of alloys such as Permalloy and Sendust deteriorate as a result, resulting in high saturation magnetic flux. A portion of the density magnetic layer 17 cannot function as a core during reproduction (and the gap during reproduction widens).Furthermore, since metal elements such as PB are precipitated on the glass of the non-magnetic portion 16, This may reduce the strength of the glass or cause damage to the magnetic recording medium during recording and reproduction.

Note that the same applies when metal is used as the soft magnetic material with low saturation magnetic flux density.

In this publication, air or plastic is used for the non-magnetic portion 16, but if air is used, the magnetic powder of the magnetic recording medium will adhere to the gap portion and the medium will be demagnetized. Furthermore, since plastic is soft, even when plastic is used, magnetic powder adheres to it in the same way as when air is used, the medium is demagnetized, and its strength is insufficient.

The present invention was made in view of these circumstances,
It has high strength, can prevent damage to the magnetic recording medium, can ensure accurate gap length, has good recording and playback characteristics such as override characteristics and resolution, does not deteriorate, has stable temperature characteristics, and has no variation in characteristics. An object of the present invention is to provide a magnetic head for both recording and reproduction, which is advantageous in terms of manufacturing and is capable of high-density recording.

Means for Solving the Problems> Such objects are achieved by the following (1) to (.1) of the present invention.

(1) A first core having a low saturation magnetic flux density amorphous thin film having a saturation magnetic flux density lower than that of the core formed on the surface facing the gap portion, and a first core having a low saturation magnetic flux density amorphous thin film having a saturation magnetic flux density higher than that of the core formed on the surface facing the gap portion; a second core on which a saturation magnetic flux density alloy thin film is formed, the saturation magnetic flux density of the low saturation magnetic flux density amorphous thin film is 1500 to 3000 G, and the first core and the second core are A magnetic head characterized by being integrally bonded via a non-magnetic part of silicon oxide.

(2) The saturation magnetic flux density of the high saturation magnetic flux density alloy thin film is
(3) The magnetic head according to (1) or (2) above, which is used for a magnetic recording medium having a coercive force of 9000e or more.

(4) On the opposite side of the front surface of the gap part, PbO:
'60-go weight %, B20. : 1 to 15 weight%, Si
The magnetic head according to any one of the chair phases (1) to 3) above, which has a reinforcing material of lead borosilicate glass containing 5 to 20% by weight of O2.

<Function> During recording, the magnetic head of the present invention is capable of recording with a wide gap because the amorphous thin film with a low saturation magnetic flux density is magnetically saturated and this thin film acts as part of the gap. Furthermore, since a strong magnetic flux can be applied to the magnetic recording medium from the high saturation magnetic flux density alloy thin film, effective recording can be performed on a medium having a high coercive force. During reproduction, the /Ii leakage magnetic flux from the magnetic recording medium is minute and the permeability of the low saturation magnetic flux density amorphous thin film is high, so the low saturation magnetic flux density amorphous thin film acts as a part of the core, and the narrow gap It is possible to perform playback using

Further, in the magnetic head of the present invention, since the non-magnetic portion is formed of a non-magnetic material such as silicon oxide, no reaction between the non-magnetic portion and metal occurs.

Therefore, the magnetic properties of high saturation magnetic flux density alloy thin films and low saturation magnetic flux density amorphous thin films are not degraded, the reproduction gap is prevented from widening, and furthermore, the magnetic recording medium is not damaged during recording and reproduction. do not have.

<Specific structure of the invention> A preferred embodiment of the magnetic head of the present invention is shown in FIG.

The magnetic head shown in FIG. 1 includes a first core 1 on which a low saturation magnetic flux density amorphous thin film 5 having a saturation flux density lower than that of the core is formed on a surface facing the gap part; A second core 2, on which a high saturation magnetic flux density alloy thin film 7 having a saturation magnetic flux density higher than that of the core is formed on the opposite surface of the side gap part, is joined and integrated via a non-magnetic part 6 made of silicon oxide, and the lead A light core is formed.

Further, the second core 2 is integrally joined to the third core 3 via the non-magnetic portion 63 to form an erase core.

A reinforcing material 8 is provided on the opposite side of the gap portion from the front surface 1 in order to increase the strength of the magnetic head.

A read/write coil 9 is wound around the first core, and a third
An erase coil lO is wound around the core 3.

In the present invention, the first core 1, the second core 2, the third core 3
It is also preferable that the back core 4 is composed of the ferrite 1-.

The ferrite used is not particularly limited, but it is preferable to use Mn-Zn ferrite or N1-Zn ferrite depending on the purpose.

As Mn-Zn ferrite, Fe20350-60
It is preferable that the amount of ZnO is about 3 to 25 mol%, with the remainder being substantially MnO.

In addition, NL-Zn ferrite exhibits excellent properties especially in the high frequency range, and its preferred composition is as follows:
Fe1O3 is about 30 to 60 mol%, NiO is about 15 to 50 mol%, and ZnO is about 5 to 40 mol%.

The DC saturation magnetic flux density of the first core 1, second core 2, third core 3, and back core 4 is preferably 4,000
~6,000G, more preferably 4,500~5,50
It is assumed to be 0G. If the saturation magnetic flux density is less than the above range,
In addition to reducing playback sensitivity due to lower impedance,
Thermal stability decreases because the Curie temperature decreases. Moreover, when the above range is exceeded, magnetostriction increases, the characteristics as a magnetic head deteriorate, and magnetization becomes easy.

The initial magnetic permeability of the first core 1, second core 2, third core 3, and back core 4 at 500 kHz is 3.000 to 5.0
00, and the coercive force is preferably 0.30e or less.

The high saturation magnetic flux density alloy thin film 7 is provided to generate a high density magnetic flux during recording and to perform effective recording on an aerated recording medium having a high coercive force.

In the present invention, the high saturation magnetic flux density alloy thin film 7 is preferably formed from an alloy containing Fe and Si.

Further, in order to avoid uneven wear on the sliding surface of the magnetic head, it is preferable to use an alloy having wear resistance comparable to that of the low saturation magnetic flux density amorphous thin film 5 described later.

The DC saturation magnetic flux density of the high saturation magnetic flux density alloy thin film 7 is preferably 9,000 to 14.0OOG, more preferably 9,000 to 11.0OOG. If the saturation magnetic flux density is less than the above range, high-density magnetic flux cannot be generated, making it difficult to record on a high coercive force magnetic recording medium and making it unsuitable for high-density recording.

When the above range is exceeded, magnetostriction increases significantly, magnetic permeability decreases significantly, and coercive force reaches several Oersteds or more, so residual magnetization exists, causing recording demagnetization and S
/N deterioration and increase in recording current occur.

In addition, the initial magnetic permeability at 500 kHz is 500 to 3.00.
0, especially about 1,000 to 3,000, coercive force is 0.2
It is preferable that it is 0e or less.

As such a high saturation magnetic flux density alloy, Fe-Al2
-3i alloy (sendust) Fe-Ga-Si alloy or Fe-Si alloy is preferred.

In addition to Sendust, Fe-Aj2-3i alloys include
22 to 6% by weight of AJ, 6 to 12% by weight of Si, and the balance is Fe, or 3% by weight of additional elements such as Cr
For Fe-Ga-3i alloys containing less than a certain amount, 5 to 15% by weight of Ga, 7 to 20% by weight of Si, and the balance F.
Preferably, the Fe-Si alloy is S
It is preferable that the i is 0.5 to 10% by weight and the balance is Fe, and particularly preferably the Si is 1 to 6% by weight and the balance is Fe.

Note that an amorphous magnetic material can also be used for the high saturation magnetic flux density alloy thin film 7.

The film thickness of the high saturation magnetic flux density alloy thin film 7 is preferably 0.2
-5-1, more preferably 0.5-3-.

If the film thickness is less than the above range, the volume of the high saturation magnetic flux density alloy thin film as a whole becomes insufficient and saturation is likely to occur, making it difficult to sufficiently achieve the above effects. Moreover, when the above range is exceeded, not only the wear of the high saturation magnetic flux density alloy thin film increases, but also the eddy current loss increases.

By having such a high saturation magnetic flux density alloy thin film, the magnetic head of the present invention has a coercive force of 9000e or more, especially 9000e or more.
Effective recording can be performed on magnetic recording media of 0.00 to 1.5000 e.

The low saturation magnetic flux density amorphous thin film 5 functions as a gap together with a non-magnetic portion 6 (described later) during recording, and serves as a gap during reproduction.
As a part of core 1, it is a dara.

Low saturation magnetic flux density The saturation magnetic flux density of amorphous thin III 5 at direct current is 1,500 to 3,0OOG, preferably 1,8
00 to 2,500G.

A low saturation magnetic flux density amorphous thin film whose saturation magnetic flux density is less than the above range has a low Curie point and is therefore thermally unstable, resulting in unstable temperature characteristics.

Furthermore, in this case, the resolution will decrease.

Note that the resolution is, for example, converting the output of 1f to VHt, 2f
When the output of is V21, (v zr/ v +r
) X 100 [%].

Furthermore, in this case, an extremely high override characteristic value can be obtained, but conversely, since the override 1~ characteristic is too high, override recording is performed with another magnetic head on the medium recorded with this magnetic head. In this case, erasing by overwriting becomes difficult.

If the saturation magnetic flux density exceeds the above range, the override characteristics will deteriorate.

The initial magnetic permeability of the low saturation magnetic flux density amorphous thin film 5 at 500 kHz is 500 to 3,000, particularly 1.000 to 3,00.
0, coercive force is 0. It is preferable that it is 20e or less. If the initial magnetic permeability is less than the above range, it will be difficult for the low saturation magnetic flux density amorphous thin film 5 to function as a part of the second core 2 during reproduction, and the performance as a narrow gap magnetic head cannot be expected. . Note that the higher the initial magnetic permeability, the higher the reproduction output, so it is preferable that the initial magnetic permeability of the low saturation magnetic flux density amorphous thin film 5 is higher. However, the low saturation magnetic flux density amorphous thin film 5 having the composition described below is An initial permeability of about 1,000 to 3,000 can be obtained.

Moreover, the low saturation magnetic flux density amorphous thin film 5 in the present invention is
Even if the film is made thinner, a low coercive force of 0.20e or less can be obtained.

In the present invention, the low saturation magnetic flux density amorphous thin film 5 is CO
, one or more of Fe, Ni and Cr, and Si, B, P
and one or more of C, or Co and one or more of Zr, Hf, Ti, Y, Si and B,
(2) It is preferable that the composition contains one or more of Nb, Ta, Cr, MO, and W. This moderate composition facilitates amorphization and obtaining desired properties.

Co, one or more of Fe, Ni and Cr, Si, B
The low saturation magnetic flux density amorphous thin film 5 containing one or more of , P, and C preferably has an atomic composition represented by the following formula in particular from the viewpoint of obtaining the above-mentioned 6H characteristics.

Formula (GO+-p-q-r Fe, Ntq Cr
r) l-xL In the above formula, M represents one or more of Si, B, P, and C (7), and 0.05≦x≦0.3.0
≦p≦0.15, 0≦q≦0.55, and 0≦r≦0.1. In this case, it is preferable that 0.04≦p+q+r≦0.2.

Moreover, it is preferable that M is a combination of 2 to 4 types including Si+B, B+P, or JP+C. In this case, the content ratio of each element is arbitrary.

In addition, in the above composition, ・Ti, Mn, R
It may contain at least 10% by weight of one or more transition metal elements such as u, Rh, Pt, Os, Nb, Zr, Hf, Ta, and W.

Further, metalloid elements such as Ge and Aβ may be contained in an amount of 10% by weight or less of the total weight.

By having the composition as described above, the wear resistance of the low saturation magnetic flux density amorphous thin film is improved, and the film formation rate is also improved.

In addition, a low saturation magnetic flux density amorphous thin film containing Co, one or more of Zr%Hf, Ti%Y, Si and B, and one or more of Nb, Ta, Cr, MO and W The ratio of each element in No. 5 is preferably as shown below in order to obtain the above-mentioned magnetic properties.

The Co content is preferably 70 to 80 at%, more preferably 72 to 78 at%.

Note that a part of Co may be replaced with Fe, Ni, and Mn. It is preferable that the amount of these elements substituted for Co is 30 at % or less in total.

The content of the element selected from the group of Zr, Hf, Ti, Y, Si, and B is preferably 30 at% or less, particularly 5 to 25 at%.
It is at%.

Further, the content of an element selected from the group of ■, Nb, Ta, Cr, Mo, and W is preferably 30 at% or less, especially 5
~25at%.

The film thickness of the low saturation magnetic flux density amorphous thin film 5 is preferably 0.
3 to 5-1 scales, more preferably 0.6 to 2 scales.

If the film thickness is less than 0.3, the difference in effective gap length during recording and playback will be small (and it will not be possible to satisfy both recording and playback characteristics. If it exceeds this, the effective gap length during recording will become too wide, and the power required for recording will increase.

The high saturation magnetic flux density alloy thin film 7 and the low saturation magnetic flux density amorphous thin film 5 described above are preferably formed by various known vapor phase deposition methods such as sputtering, vapor deposition, and CVD. It is preferable to form by sputtering method.

If induced magnetic anisotropy occurs in these deposited thin films, the anisotropy can be removed by heat treatment at a temperature below the crystal temperature in a static magnetic field or a rotating magnetic field.

1st core 1, 2nd core 2, 3rd core 3, back core 4,
If the saturation magnetic flux densities of the high saturation magnetic flux density alloy thin film 7 and the low saturation magnetic flux density amorphous thin film 5 are within the above ranges, high resolution can be obtained as a magnetic head. Further, since good values of override characteristics of -30 dB or less and -40 dB or more can be obtained, the magnetic head of the present invention can perform override recording well.

The non-magnetic portion 6 functions as a gap during reproduction, and is made of a non-magnetic material such as silicon oxide.

When a nonmagnetic material of silicon oxide is used, reaction with metal can be prevented and good recording and reproducing characteristics can be obtained.

Further, the non-magnetic portion 63 serving as an erase gap is formed of a non-magnetic material such as SiO□ or glass or a non-magnetic space.

The thickness of the non-magnetic part 6, that is, the gap length during reproduction, is
Preferably 0.1 to 2.0 μs, more preferably 0.1
~1. It is preferable to have a roughness of 0.0, more preferably about 0.1 to 0.4 scales. Within this range, high-density recording can be performed satisfactorily.

In the present invention, in order to increase the strength of the magnetic head,
A reinforcing material 8 is used.

The reinforcing material 8 contains 60 to 80% by weight of PBO and B20. It is preferable to use lead borosilicate glass containing 1 to 15% by weight of SiOz and 5 to 20% by weight of SiOz.

In particular, pbo is 65-75% by weight and B20° is 4-13% by weight.
It is preferable to contain 6 to 15% by weight of SiO□.

Outside the above range, the working point Tw of the glass (working point Tw refers to the temperature at which the viscosity of the glass becomes 10' poise) becomes high, and the amorphous thin film is crystallized during welding.

In addition to the above composition, the reinforcing material 8 of lead borosilicate glass preferably contains at least one of Aρiox, Zno, and B i z Os. In this case, the proportion of each substance is as follows: AQ-Os is 5% by weight or less, preferably 3% by weight or less, particularly preferably 0.5 to 3% by weight.
% by weight, ZnO is 12% by weight or less, preferably 8% by weight or less, particularly preferably 2 to 8% by weight, BizOi is 15% by weight or less, preferably 10% by weight or less, particularly preferably 3 to 10% by weight. % is preferable.

Working point T w of lead borosilicate glass having the above composition
is 450 to 580°C. Therefore, crystallization of the amorphous thin film rarely occurs during welding (by using such lead borosilicate glass, it is possible to reduce the crystallization of the amorphous thin film without impairing the 6 competitive properties of the amorphous thin film. Welding can be performed.

Furthermore, the lead borosilicate glass contains 6% by weight or less of Na2O, 3% by weight or less of 20, and 2% by weight of NiO.
Below, CrO is 2 weight% or less, Coo is 2 weight% or less,
Fez Os may be contained in an amount of 2% by weight or less.

The lead borosilicate glass described above is manufactured by a conventional method, and the welding is carried out by the method of Tsutomi at a welding temperature near the working point.

Note that lead borosilicate glass also reacts with metal, but since the welded portion of the reinforcing material is on the opposite side of the front surface of the gap, there is almost no effect.

The reit light coil 9 wound around the first core 1 and the nose coil 10 wound around the third core 3 are installed by attaching a bobbin in Fig. 1, but they are directly attached to the core. It may be rolled.

The magnetic head of the present invention is integrated with a slider as necessary and assembled into a head assembly.

We also use various magnetic heads such as floppy heads that perform overwrite recording such as tunnel erase types such as so-called laminate types and bulk types, or read/write types that do not have an erase head, and heads for 81 recording machines such as monolithic types and composite floating types. Used as a head.

Further, by using the magnetic head of the present invention described above, override recording of various known methods can be performed.

<Example> Hereinafter, the present invention will be explained in further detail by giving specific examples of the present invention.

Example 1 As shown in FIG. 1, the first core 1 has a low saturation magnetic flux density amorphous thin film 11115 formed on the surface facing the gap portion, and the surface facing the gap portion on the first core 1 side. The second core 2 on which the high saturation magnetic flux density alloy thin film 7 is formed is S i O2
The second core 2
The third core 3 is joined and integrated through a non-1n-i part 63 made of S i O2, and the back core 4 is joined to the lower side of the core block, and on the opposite side of the front surface of the gap part, lead is A magnetic head sample having a reinforcing material 8 of borosilicate glass was manufactured. For comparison, we also manufactured one in which the non-magnetic parts 6 and 63 were made of glass, and one without a reinforcing material. The composition of the glass used for the non-magnetic part of the comparative magnetic head assembly was the same as that of the reinforcing material 8.

The composition of the lead borosilicate glass used as the reinforcing material 8 is 70Pb011Ba Os-Losing in weight percentage.
−3Aff, 0°−6ZnO, and the working point T of the glass
The temperature was 530°C.

Table 1 shows the composition, DC saturation magnetic flux density, initial magnetic permeability, and coercive force of the high saturation magnetic flux density alloy thin film 7. The film was formed by sputtering, and the film thickness was 2. It was set as opm.

Further, Table 1 shows the composition of the low saturation magnetic flux density amorphous thin film 5, the saturation magnetic flux density at direct current, the clear li-temperature, the IRla force, and the Curie point. Note that the film was formed by sputtering, and the film thickness was 1.0 mm.

The material of the first core 1, second core 2, third core 3, and back core 4 is Mn-Zn ferrite binding, DC saturation magnetic flux density +: J: 4500 G, and initial magnetic permeability is 3000.
, coercive force [:J:0.10e].

The thickness of the non-magnetic portion of the magnetic heads of the present invention and comparison is as follows:
The non-magnetic part 6 was set to 0.4 scale, and the non-magnetic part 63 was set to 2.5 μs. Further, the number of coil turns of the read/write coil 9 was 100×2 turns, and the number of coil turns of the erase coil 10 was 100 turns.

Using this magnetic head and a floppy disk with a coercive force of 9000e, the following characteristics were measured at a track width of 1201JJ11.

In addition, during the measurement, a low saturation magnetic flux density amorphous thin film was used.
The floppy disk was used as a progress side.

(Override characteristics) A 1.25 MHz 1f signal was recorded, and then a 2.5 MHz 2f signal was overwritten thereon.

The signal output multiplied by if with respect to the output of the 2f signal was calculated, and the override characteristics were evaluated.

Note that if this value exceeds 130 dB, it is insufficient as an override characteristic.

Further, if this value is less than 140 dB, compatibility with other magnetic heads cannot be achieved.

(Resolution) A 1f signal of 1.25 MHz was recorded, and the output of this signal was defined as vlf. Separately, a 2.5 MHz 2f signal was recorded, and this output was designated as V 2f. From these,
The resolution was calculated using the following formula.

Formula CVxt/Vre) X 1 00
[%] Note that a resolution of less than 70% is not practical.

Table 1 shows the results.

From Table 1, it is clear that the magnetic properties of the thin films of comparative magnetic head samples No. 7 and Nc) and No. 8, whose non-magnetic parts were made of glass, have deteriorated, and the gap during playback is wide. As a result, it can be seen that the recording and reproducing characteristics are reduced. Further, as a result of observing the magnetic recording media on which recording and reproduction were performed using No. 7 and No. 8 using a scanning electron microscope, it was found that the surfaces of the magnetic recording media were damaged. Note that no change was observed in the surface of the magnetic recording medium using the present invention before and after use.

Furthermore, in the comparative magnetic head sample No. 7, which did not have a reinforcing material, half of the quanta were broken at the gap portion during the manufacturing process, and only a small number of the heads were able to be evaluated for their characteristics.

<Effects of the Invention> The magnetic head of the present invention has a high saturation magnetic flux density alloy thin film and a low saturation magnetic flux density amorphous thin film on the opposing surfaces of the gap portion of the core, and can satisfy both resolution and override characteristics. It is.

Second, in the present invention, the non-magnetic part is made of silicon oxide, which is non-magnetic.
Since it is formed from A, reaction with metal can be prevented.

Therefore, the magnetic properties of the high saturation magnetic flux density alloy thin film and the low saturation magnetic flux density amorphous thin film are not deteriorated, and the reproduction gap can be prevented from widening. As a result, an accurate gap length can be ensured and good recording and reproduction characteristics can be obtained.

Furthermore, damage and demagnetization of the magnetic recording medium can be prevented during recording and reproduction.

[Brief explanation of the drawing]

FIG. 1 is a side view showing one embodiment of the magnetic head of the present invention. FIG. 2 is a partial side view showing a conventional magnetic head. Explanation of symbols 1...First core 2...Second core 3...Third core 4...Back core 5...Low saturation magnetic flux density amorphous thin film 6...Non-silicon oxide Magnetic part 63...Nonmagnetic part 7...High saturation magnetic flux density alloy thin film 8...Reinforcement material 9...Read/write coil 10...Erase coil 15...Oxide-based soft magnetic thin film 16... ...Nonmagnetic portion 17...High saturation magnetic flux density magnetic layer F[0,1 Patent applicant: TDC Co., Ltd. Agent Patent attorney: Yo Ishii -k'Q'h-
1 Yumini procedural amendment (voluntary) 1. Indication of the case Patent Application No. 328520 of 1988 2. Name of the invention Magnetic head 3. Relationship with the case of the person making the amendment Name of the patent applicant Title TDC Co., Ltd. 4. Agent address 2S, 3rd floor, Tenjin Yasakakosan Building, 3-23-1 Yushima, Bunkyo-ku, Tokyo 113 839-0367 Fax, 839-0327 Name (8286) Patent attorney Yo Ishii -1';
I-j 5. Subject of correction
・Contents of amendments to columns 6 of "Claims" and "Detailed Description of the Invention" of the Sohni Specification (1) The "Claims" of the specification will be corrected as shown in the attached sheet. (2) “Holding force” on page 8, line 5 of the specification is “coercive force”
Correct. (3) Correct rMOJ on page 17, line 9 to "MO". (4) Correct rMOJ in the second line from the bottom of page 18 to "MO". 2. Scope of Claims (1) A first device in which a low saturation magnetic flux density amorphous thin film having a saturation magnetic flux density lower than that of the core is formed on the opposing surface of the gap portion.
a core, and at least a second core having a high saturation magnetic flux density alloy thin film having a higher saturation magnetic flux density than the core formed on a surface facing the gap portion, and the saturation magnetic flux density of the low saturation magnetic flux density amorphous thin film. is 1500-3000G,
A magnetic head characterized in that the first core and the second core are joined and integrated via a non-magnetic portion of silicon oxide. (2) The saturation magnetic flux density of the high saturation magnetic flux density alloy thin film is
3. The magnetic head according to claim 1, which has a power of 9,000 to 14,000 G. (3) The magnetic head according to claim 1, which is used for a magnetic recording medium of LL229,000e or higher. (4) On the opposite side of the front surface of the gap part, PbO:
60-80% by weight, 13zOs: 1-15% by weight, S
4. The magnetic head according to claim 1, further comprising a lead borosilicate glass reinforcing material containing 5 to 20% by weight of iO2.

Claims (4)

[Claims] (1) A first core having a low saturation magnetic flux density amorphous thin film having a saturation magnetic flux density lower than that of the core formed on the surface facing the gap portion, and a first core having a low saturation magnetic flux density amorphous thin film having a saturation magnetic flux density higher than that of the core formed on the surface facing the gap portion; a second core on which a saturation magnetic flux density alloy thin film is formed, the saturation magnetic flux density of the low saturation magnetic flux density amorphous thin film is 1500 to 3000 G, and the first core and the second core are A magnetic head characterized by being integrally bonded via a non-magnetic part of silicon oxide. (2) The saturation magnetic flux density of the high saturation magnetic flux density alloy thin film is
The magnetic head according to claim 1, which has a power of 9000 to 14000G. (3) The magnetic head according to claim 1 or 2, which is used for a magnetic recording medium having a coercive force of 9000e or more. (4) On the opposite side of the front surface of the gap part, PbO:
60-80% by weight, B_2O_3:1-15% by weight, S
4. The magnetic head according to claim 1, further comprising a lead borosilicate glass reinforcing material containing 5 to 20% by weight of iO_2.