JPH03156709A - Floating type magnetic head - Google Patents

Abstract

PURPOSE:To lessen the fluctuation in peak intervals at the time of the repetition of recording and reproducing and to prevent the deviation of the peaks from a data window even in high-density recording by setting the angle formed by the respective magnetic core piece <100> directions existing within the 110 face of a magnetic core and gap facing surfaces over 26 deg. over and 45 deg. or under. CONSTITUTION:This magnetic head has a nonmagnetic slider 1, a slit part 2 provided in one side race part 5 of the slider 1, the magnetic ore 3 embedded in the slit part 2 and glass 4 for fixing the magnetic core 3. The magnetic core is formed of a C type core piece 21 and I type core piece 22 consisting of single crystal ferrite, the 110 face of which is nearly parallel with the main magnetic path forming surface and a magnetic thin film 23 consisting of an Fe-Al-Si alloy formed on the I type core piece 22. The C type core piece 21 and the glass part 25 joining the I type ore piece 2 are provided in the upper part of the space 24 for winding. The magnetic gap 27 is formed of a gap regulating film consisting of a nonmagnetic material, such as SiO2. The higher- density recording with the smaller bit shift is possible in this way.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a floating magnetic head that is used in a magnetic disk drive by being floated very slightly above the surface of a recording medium. The present invention relates to the structure of a floating composite magnetic head that is formed with a metal magnetic thin film having a magnetic flux density and is suitable for recording and reproducing from a high coercive force recording medium.

[Prior Art] As a magnetic head used for writing and reading information in a magnetic disk device, for example, US Pat.
, No. 416 and Japanese Patent Publication No. 57-569, there are floating magnetic heads having structures such as those shown in Japanese Patent Publication No. 57-569. This floating magnetic head has a magnetic head constructed by providing a magnetic gap at the rear end of a slider made of a high permeability oxide magnetic material, and the entire head is made of a high permeability oxide magnetic material. There is. However, in floating magnetic heads with such a configuration, the saturation magnetic flux density of ferrite, which is a high permeability oxide magnetic material, is about 5.0OOG, so it has recently begun to be used to meet the demands for higher recording densities. There is a drawback that sufficient recording cannot be performed on a recording medium with a high coercive force.

In order to solve this problem, magnetic heads have also been used in which a metal magnetic thin film with a high saturation magnetic flux density is formed on the surface facing the gap. That is, for example, JP-A-58-1
As disclosed in No. 4311, this is a floating magnetic head in which a slider and a magnetic core piece are made of ferrite, and a metal magnetic thin film having a high saturation magnetic flux density is provided only on the surface facing the magnetic gap. However, even if this structure is improved, the problem still remains that the inductance after a predetermined winding is applied to the magnetic transducer is large, which lowers the resonance frequency and makes recording and reproduction at high frequencies disadvantageous. This is because in the magnetic head having the above structure, the inductance becomes large due to the fact that the entire magnetic head is made of a magnetic material.

Therefore, it is considered that the magnetic circuit should be made smaller in order to lower the inductance. From this point of view, a floating type composite magnetic head in which a magnetic core is embedded and fixed in a non-magnetic slider is disclosed in U.S. Patent No. 3,562,44.
It was first disclosed by No. 4. In addition, the present inventors proposed a desirable shape of a floating type composite magnetic head in which a magnetic core is embedded in a non-magnetic slider in Japanese Patent Laid-Open No. 199219/1983. The characteristics of this floating composite magnetic head are that, compared to the floating magnetic head whose entire magnetic head is made of a magnetic material, the inductance after winding the magnetic transducer is small, and it is capable of recording at high frequencies. is advantageous.

Furthermore, in order to obtain a floating composite magnetic head with low inductance and sufficient recording capability for high-coercivity recording media, Mn-Zn ferrite with high saturation magnetic flux density is used as a substrate, and additional layers are added to the nonmagnetic magnetic gap. A magnetic head in which a magnetic core coated with a thin film magnetic material with a high saturation magnetic flux density is embedded in a non-magnetic slider is superior, but as an example of such a floating type composite magnetic head, the present inventors reported
There is one disclosed in No.-154310.

On the other hand, as magnetic heads become smaller, thinner, and have narrower tracks in response to the demand for higher capacity magnetic recording, a problem arises in that the recording and reproducing output of the magnetic head becomes smaller. Therefore, in order to improve recording and reproducing characteristics, for example, VTR
Japanese Patent Publication No. 62-18965 and Japanese Patent Application Laid-open No. 56-163516 disclose magnetic heads using single-crystal MnZn ferrite.

That is, Japanese Patent Publication No. 62-18965 has two high permeability magnetic bodies facing each other across a magnetic gap, and at least one of the high permeability magnetic bodies is a single crystal M.
Consisting of n -Z n M n Z n ferrite,
At least one single crystal M n Z n ferrite (
110) plane is made almost parallel to the main magnetic path forming plane, and (
110) The angle O between the <100) direction existing in the plane and the plane where the magnetic gap is formed is 5 to 40 degrees or 80 degrees to
12o°, and at least a glass having a shrinkage rate lower than that of the ferrite when the temperature is lowered from the glass fixing temperature to room temperature is melted and adhered to the high magnetic permeability magnetic material surface near the side surface of the magnetic gap. A magnetic head is shown. Furthermore, the method disclosed in Japanese Patent Application Laid-open No. 163513/1983 uses a single crystal MnZn ferrite containing SnO as a solid solution.
This is a magnetic head constructed similarly to No. 8958.

[Issues to be Solved by the Invention] Further, for example, in a magnetic disk device, information transferred as an electrical signal is recorded on a magnetic disk by a magnetic head as the presence or absence of magnetization reversal.

Reproduction of recorded information is also performed by a magnetic head, which outputs a signal waveform having a peak corresponding to magnetization reversal of the magnetic disk, detects this peak, and reproduces the recorded information. FIG. 13 shows a schematic explanatory diagram of the processing of the reproduced signal in the reproduction process. The output of the magnetic head 41 is amplified by a preamplifier 42, and then passed through a filter 43 for removing noise, thereby obtaining a signal waveform as shown in FIG. 4(a), for example.

Thereafter, the differentiating circuit 44 converts the peak of the reproduced signal into a zero cross to obtain a signal waveform (b), and then the comparator 45 generates a peak pulse corresponding to the zero cross to obtain a signal waveform (C). A pulse called a data window is used to discriminate from this peak pulse to 1"O". This data window is generated by PLO (Phase Lock), which is transmitted in synchronization with the peak pulse.
0scillater) output signal waveform of the circuit 46 (d)
is used. If the peak pulse is within the data window time, if it is not "1", it is determined to be "O" and the recorded information is reproduced.

Therefore, in order to accurately record and reproduce information, it is necessary to ensure that the peak pulse falls within the data window. However, in an actual device, the peak pulse deviates from the recorded position.

The main causes of this are interference between adjacent waves called pattern peak shift and noise superimposed on the reproduced signal.
In addition, there is also irregular behavior of the reproduced waveform, which is thought to be caused by the magnetization reversal mechanism of the head.

On the other hand, as mentioned above, in recent years there has been a demand for further increases in the storage capacity of magnetic disk drives, and for this purpose it is necessary to increase the linear recording density.

Improving linear recording density means reducing the interval between magnetization reversal positions recorded on a magnetic disk, which inevitably reduces the interval between reproduced peak pulses, and also reduces the interval between data windows that occur in synchronization with the peak pulses. Since the data window width is reduced, the data window width also becomes smaller.

Therefore, when the position of the peak pulse deviates due to the various causes mentioned above, it tends to fall out of the data window.

That is, the higher the linear recording density, the smaller the allowable amount of deviation of the peak pulse with respect to the data window.

However, in a floating magnetic head with a conventionally known configuration, the deviation of the peak pulse position is quite large, and recently, 30 K P CI (Kilo Flax C
It has been pointed out that linear recording densities higher than 1000 yen (hang per inch) are unusable due to the large number of errors, and there has been a desire for a magnetic head with higher performance.

SUMMARY OF THE INVENTION In order to meet the above-mentioned demands, an object of the present invention is to provide a floating composite magnetic head that reduces variation in peak intervals during repeated recording and reproduction, and that prevents peaks from deviating from the data window even during high-density recording. It is.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a method in which a metal magnetic thin film is formed on at least one gap-opposing surface of a pair of magnetic core pieces that face each other across a non-magnetic gap. A flying type magnetic head having a magnetic core portion in which a pair of core pieces are joined by primary glass, and a slider supporting the magnetic core, wherein the magnetic core piece is made of single crystal M n
It is made of Zn ferrite, and its (110) plane is made almost parallel to the main magnetic path forming plane, and the (110)
) The angle formed between the <100> direction of each magnetic core piece existing in the plane and the gap facing surface is more than 26° and less than 45°.

In the present invention, the metal magnetic thin film is Fe-N
i-based alloy, Fe-Al-3i alloy, and other known alloys can be used. Furthermore, as the single crystal ferrite constituting the magnetic core piece, single crystal M n of a known composition is used.
Zn ferrite can be used. These are appropriately selected and used depending on the characteristics of the magnetic recording medium used.

In the present invention, the magnetic core is made of single-crystal ferrite, but the technical concept disclosed in the above-mentioned Japanese Patent Application Laid-open No. 56-163513 or Japanese Patent Publication No. 62-18958 is based on a pair of magnetic core pieces. When joining glass, tensile stress is generated in the ferrite near the magnetic gap,
The existence of this retirement stress controls the magnetic anisotropy of the ferrite to improve recording and reproducing characteristics, and also takes into consideration the wear resistance of the magnetic tape as a recording medium.

Therefore, the above-mentioned publications do not suggest application to a floating magnetic head that operates essentially without contact with a recording medium. Furthermore, the presence of stress in a magnetic core made of single-crystal MnZn ferrite with a metal magnetic thin film is different from that in the case of ferrite alone, so it cannot be applied immediately.

Furthermore, in a floating composite magnetic head in which the magnetic core is embedded within a non-magnetic slider, the presence of stress becomes even more complex because not only the secondary glass but also the magnetic core is fixed in the slider slit with secondary glass. Therefore, it cannot be applied immediately with the expectation of the effects disclosed in the publication.

In the present invention, the reason why the angle formed between the <100> direction of each magnetic core piece existing in the (110) plane of the magnetic core and the gap facing surface is greater than 26° and less than 45° is as will be described later. This is because the deviation of the peak pulse is extremely small in this range, and excellent recording and reproducing characteristics can be obtained.

[Examples] Hereinafter, the present invention will be explained in more detail based on Examples, but the present invention is not limited to the scope of these Examples.

(Embodiment 1) FIG. 1 shows a perspective view of the overall configuration of an embodiment of a floating type composite magnetic head according to the present invention. In the figure, 1 is a non-magnetic slider, 2 is a slit section provided in one of the sight rails 5 of the slider 1, 3 is a magnetic core embedded in the slit section 2, and 4 is a glass that fixes the magnetic core 3. . Thermal expansion coefficient 105-11 for slider 1
5X10-'/'C1 CaTi with porosity of 0.5% or less
0. It is desirable to use a non-magnetic ceramic consisting of:

FIG. 2 is an enlarged perspective view of the magnetic core 3.

21 and 22 are C made of single crystal ferrite, respectively.
These are magnetic core pieces called a type core piece and a Go type core piece, and 23 is a Fe-AQ-S formed on the ■ type core piece 22.
This is a magnetic thin film made of an i-based alloy. 24 is C-shaped core piece 2
This is a space for winding formed between the C-shaped core piece 21 and the ■-shaped core piece 22, and a glass portion 25 for joining the C-shaped core piece 21 and the ■-shaped core piece 22 is provided above the space. 26 is a notch for regulating the track width Tw. The magnetic gap 27 is formed by a gap regulating film made of a non-magnetic material such as Sin deposited by sputtering or the like. The tempered glass for joining the pair of magnetic core pieces may be, for example, 560 mm, depending on the material of the magnetic core pieces.
It has a softening point of ~600°C and a fixing temperature of 450-490°C, and a coefficient of thermal expansion of 93 at the fixing temperature of 30 to
˜111×10−′/′C is preferably used. The glass for fixing the magnetic core in the slit formed in the slider is appropriately selected depending on the composition of the secondary glass and the material of the slider. For example, it has a softening point of 420 to 470°C, Thermal expansion coefficient at 280℃ is 82~100X
Something like IO-'/'C is used.

The main specifications of the manufactured floating type composite magnetic head are as follows.

Gap length GQ O, 6° Gap depth Gd 2um Track width Tw 1ip Fe-Al-Si film thickness 2.2- The magnetic core 3 of this example is made of single crystal Mn-Zn ferrite, and its plane orientation is As shown in Figure 2, (110
) plane is made almost parallel to the main magnetic path forming plane. In addition, in this example, the angle θ between the <100> direction and the gap forming surface of each of the C-type and ■-type magnetic core pieces is 20
Six types of magnetic heads were fabricated with angles of 35°, 60°, 80°, 90°, and 100°.

For each magnetic head produced, its reproduction output voltage and T, -T were measured. T, and T2 are the time from the positive peak to the negative peak, T, and the time from the negative peak to the positive peak, T, as shown in Figure 3.
That is. Recording and reproduction were repeated 50 times for each magnetic head, and T3 and T were measured each time. T,
-T is an index indicating the symmetry of the waveform, and if it is O, the waveform is almost symmetrical, and it can be considered that there is no peak shift. The measurement conditions are as shown below.

Recording medium: 5-inch diameter, Go-Ni sputtered magnetic film medium, magnetic retention crab 12000e Circumferential speed: 9.75 m/s Flying height: 0.15 μm Number of coil turns: 26×2 turns Recording frequency: 4 MHz The measurement results are shown in FIG. 4. From this figure, the output voltage is determined by the angle θ between the <100> direction of each magnetic core piece and the gap forming surface.
is maximum when is about 20° and about 95°,
T, -T, 1, which indicates the asymmetry of the reproduction output, has an angle θ of 35
IT shows a minimum value at 0°, and the angle O is in the range of approximately 26° to 40°.

It can be seen that -T and l are less than l0m5ec, indicating excellent symmetry.

For comparison, we prepared a floating composite magnetic head having the same shape as the above-mentioned floating type composite magnetic head of the present invention, but with only the core material made of polycrystalline ferrite.

(The part of the magnetic head that faces the non-magnetic gap is composed of multiple crystal grains), and the reproduction output and
T, -T, l were measured. As a result, the playback output is 0.3
5 mVpp, and IT,-T,1 was about 19 nsee.

Although it is not necessarily clear why peak shifts occur in conventional floating magnetic heads using polycrystalline ferrite, the following reasons may be considered, for example.

■There are several ferrite particles near the magnetic gap,
Because the anisotropy directions of the individual ferrite grains do not match, the magnetic domain structure becomes unstable, and the magnetic domain structure changes each time recording and reproduction are repeated, which appears as output fluctuations and waveform distortion.

■If the ferrite particles near the magnetic gap are small, a portion with degraded magnetic properties will appear near the gap, making the magnetic domain structure unstable, and the magnetic domain structure will change each time recording and playback is repeated, resulting in fluctuations in output and waveform distortion. .

(2) As the recording density increases, the leakage of magnetic flux from the medium decreases, and the magnetic permeability of ferrite also decreases as the frequency increases, so the reproduction output decreases at high recording densities. Therefore, it becomes susceptible to noises such as head noise, medium noise, and amplifier noise, resulting in output fluctuations and waveform distortion.

It is thought that one or more of the above causes are the cause, but according to the present invention, a single crystal is used in which there are no multiple ferrite particles near the gap and the magnetic domain structure has a stable plane orientation, and It is thought that excellent effects can be obtained because the easy magnetization direction <100> is oriented in a direction suitable for recording and reproduction.

(Example 2) FIGS. 5 and 6 show the conventional head used as a comparative example in Example 1 and the structure shown in FIG. 1 with the <100> direction of the magnetic core piece and the gap forming surface The angle θ is 35
The results of measuring IT and -T- using the floating composite magnetic head according to the present invention, which is .degree., are shown. In addition,
The measurement conditions were a medium with Hc = 12000e, a circumferential speed of 9.7
5 m/s, flying height 0.154, recording frequency 4 MHz
was recorded, and T1 and T2 of the output were measured from the reproduced waveform.

According to FIG. 5 using the conventional head, the average of T and -T is as large as 22.5 ns, and the range of variation is also 36 ns.
13 nsec from ec, which is very large. In such a head, the data window width becomes narrow for linear recording densities of 30 KPCI or more, so there is a high probability that the peak will deviate from the data window and cause an error. Therefore, high-density recording is difficult. On the other hand, in FIG. 6, which shows the measurement results according to the present invention, it can be seen that the smaller the values of T and -T, which represent the symmetry of the waveform, the smaller the variation.

Therefore, it is clear that the floating magnetic head according to the present invention can have a smaller data window width than the conventional head using a polycrystalline ferrite core, and therefore can realize a higher linear recording density.

In addition, Figure 7 shows the bit shift Gu, which is a practical guideline.
These are the results measured using RWA201B manufactured by Zik.

The curve labeled A is the result of the head according to the present invention, and the curve labeled B is the measurement result of the conventional head. The bit shift at an error rate of 10-' is approximately 14
nsee, whereas in the head of the present invention it is about 10 ns.
ee, and the head of the present invention shows a much better value, 30
It can be seen that a linear recording density higher than KPCI can be achieved.

(Embodiment 3) FIG. 8 shows a perspective view of the overall configuration of a floating magnetic head according to another embodiment of the present invention. In the figure, 31 is a half magnetic core with a part of the floating slider, 32 is a half magnetic core with a winding groove 34, and the second half of the magnetic core is a glass 33
are joined by. 35 is a rail portion that generates floating pressure.

Both magnetic core halves 31 and 32 are made of single crystal M n
-Z n ferrite is used, and its surface orientation is (113) on the surface facing the recording medium and (33) on the surface facing the gap.
2) The angle θ at which the remagnetic core is joined so that the 100〉 direction spreads on the surface facing the recording medium is 35
°. FIG. 9 is an enlarged view of the vicinity of the gap seen from the air bearing surface side. The direction of the arrow C indicates the direction of movement of the recording medium. A Fe-AQ-5i thin film 36 is formed only on the outflow end side of the gap 37.

For comparison, a conventional head was also made using polycrystalline ferrite in the same manner as in Example 1. The conventional L\rad prepared as a comparative example has the same shape as the product of this example, but the magnetic core material is Mn-Zn polycrystalline ferrite, and the gap portion is composed of a plurality of crystal grains. The main specifications of the magnetic head produced in this example are as follows.

Gap length GQ 0.6q Gap depth Gd ion Track width Tw lltm Fe-AQ-Si film thickness 2/J1 Using the created magnetic head of the present invention and the conventional head,
The variation in T, -T, and bit shift were measured.

The measurement conditions are the same as in Example 1.

The measurement results are shown in FIGS. 10 to 12. FIG. 10 shows the measurement results for the conventional head, and FIG. 11 shows the measurement results for the head of the present invention. Comparing both figures, the values of T and -T, which indicate waveform asymmetry, are smaller in the head of the present invention, and the variation thereof is also smaller.

Furthermore, FIG. 12 shows the results of measuring bit shifts, which serve as a practical guideline. It is clear that the curve D is based on the present invention and is better than the conventional head shown as curve E. Furthermore, the bit shift of this embodiment is smaller than that of the first embodiment. That is, although the inductance of this structure is larger than that of the first embodiment, it has the advantage that more favorable results can be obtained in terms of bit shifting.

[Effects of the Invention] As detailed above, the floating magnetic head according to the present invention has small variations in peak shift and good waveform symmetry. Therefore, the bit shift is small and higher density recording is possible, which has great industrial effects.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a schematic configuration of a floating type composite magnetic head according to an embodiment of the present invention, FIG. 2 is an enlarged perspective view of a magnetic core in the floating type composite magnetic head of FIG. 1, and FIG. 3 is a T ,, T, and the measurement position of the output. Figure 4 shows the relationship between the angle θ formed by the (100) direction of the magnetic core piece and the surface facing the gap, the output voltage, IT, -T, l. figure,
Figure 5 is a distribution diagram of T, -T, and output when recording and reproducing are repeated 50 times in a conventional floating type composite magnetic head, and Figure 6 is a distribution diagram of T, -T, and output when recording and reproducing are repeated 50 times in a floating type composite magnetic head of the present invention. Figure 7 is a diagram showing the distribution of T, -T, and output when repeated. Figure 7 is a diagram showing the measurement results of bit shifts by the floating composite magnetic head according to the present invention and the conventional floating composite magnetic head. A perspective view of a floating magnetic head according to another embodiment of the invention, FIG. 9 is an enlarged view of a portion near the gap seen from the air bearing surface side, and FIGS.
Distribution diagram of T, -T and output when recording and reproducing are repeated 50 times with the conventional floating magnetic head and the floating magnetic head of the present invention each having the structure shown in FIG.
The figure shows the measurement results of bit shifts by the head of the present invention having the structure shown in FIG. 8 and the conventional head, and FIG. 13 is a block diagram of the read circuit of the disk drive device. 1 Nislider, 2 Nislit part, 3: Magnetic core, 4:
Bonded glass, 576: Side rail, 21: C-type core piece, 22: ■-type core piece, 23: Fe-AQ-3i film, 24
: Winding window, 25: Bonded glass part, 26: Notch, 27
:Magnetic gap. Figure (0) Engraving of drawing (no change in content) Figure 1 TI-T2 (ns) Figure 7 Bit shift (nsec) Figure 10 Figure Tl-72 (ns) i[11 Figure T1-72 ( nS) Fig. 8 Fig. 4 Fig. 12 Focus shift (nsec) Fig. 3 Fig. Procedural amendment (method) % formula % 2. Name of the invention Floating magnetic head 3. Patents related to the person making the amendment case

Claims (3)

[Claims] (1) A magnetic core in which a metal magnetic thin film is formed on at least one gap-opposing surface of a pair of magnetic core pieces facing each other across a non-magnetic gap, and the pair of magnetic core pieces are joined by a glass part. and a slider supporting the magnetic core, wherein the magnetic core piece is made of single crystal MnZn.
Made of ferrite, the (110) plane of the magnetic core piece is made almost parallel to the main magnetic path forming plane, and the angle θ between the <100> direction existing in the (110) plane and the gap-opposing plane is 26°. What is claimed is: 1. A floating magnetic head characterized in that the floating magnetic head is configured such that the angle exceeds 45 degrees and is 45 degrees or less. (2) The slider is made of a non-magnetic material, the magnetic core is accommodated in a slit formed in the slider, and the secondary glass has a composition different from that of the primary glass used to join the pair of magnetic core pieces. 2. The floating magnetic head according to claim 1, wherein the floating magnetic head is fixed to the floating magnetic head. (3) The floating magnetic head according to claim 1, wherein one of the magnetic core pieces is formed integrally with the slider.