JPH011111A - magnetic head - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a magnetic head. More specifically, the present invention relates to an improvement in the physical composition of a metal thin film portion of a composite magnetic head that forms a magnetic circuit by forming a ferromagnetic metal thin film on a substrate.

(Jourai's technology) ′ With the increasing density of magnetic recording in the near future, magnetic tapes with higher residual magnetic flux density Br are being used, and in order to cope with this, magnetic heads with high magnetic flux density and narrow track width are being used. is requested.

Conventionally, such a magnetic head is disclosed in Japanese Patent Application Laid-Open No. 60-2
As disclosed in No. 23012, a thin film magnetic head is known in which a thin film of ferromagnetic metal is formed on a core made of ferromagnetic oxide using vacuum thin film forming technology, and a magnetic gap is formed between the thin films of ferromagnetic metal. .

In this conventional magnetic head, the ferromagnetic metal thin film 101 forming the track and the magnetic gap is a multi-NJ film made by alternately laminating ferromagnetic metal 101 and non-magnetic material 102, as shown in FIG. There is a tendency to obtain a predetermined track width by keeping the thickness of each layer of ferromagnetic metal 101 in μm units, for example, within about 5 μm in the case of Sendust alloy (Japanese Patent Publication No. 3,238/1983). It was believed that there is a correlation between the thickness of the magnetic film and eddy current loss, and that eddy current loss does not occur if the film thickness becomes thinner on the order of μm. For example, it was believed that eddy current loss in a high frequency band of 5 MHz would not occur if the film thickness was about 5 μm in the case of Sendust alloy, and no deterioration of frequency characteristics would occur, according to the Skindives formula.

(Problem to be solved by the invention) However, when the present inventors actually formed a multilayer thin film of sendust with a film thickness of about 5 μm, significant deterioration of frequency characteristics was actually observed in the high frequency band. . As a result of various experiments and studies conducted by the present inventors regarding this phenomenon, it was discovered that the size of the crystal grain size of the ferromagnetic metal constituting the thin film has a close relationship with the specific resistance ρ and magnetic permeability μ. I ended up doing it. In other words, as the crystal grain size increases, the magnetic permeability increases, but the specific resistance ρ decreases, which is a trade-off relationship, and as the specific resistance ρ increases, the frequency band at the time of 6 ds deterioration moves closer to the high frequency band. There was found.

The present invention was made based on this knowledge,
It is an object of the present invention to provide a magnetic head that exhibits less deterioration in a high frequency band, particularly in a high frequency band of 5 MHz.

(Means for Solving the Problems) In order to achieve the above object, the magnetic head of the present invention has a crystal grain size of a ferromagnetic metal thin film of 300 to 300 when grown on 422 planes.
The number is set at 700 people.

In addition, when the thin film metal in the above-mentioned magnetic head is Sendust alloy, the crystal grain size is 520 to 5 when grown on 422 planes.
It is characterized by having a range of 70 people.

Further, in the magnetic head of the present invention, the crystal grain size of the ferromagnetic metal thin film is in the range of 200 to 330 crystal grains when grown on 220 planes.

(Function) Therefore, taking the case where standard Sendust is used as an example, the electrical resistivity is set in the range of 72.5 to 130 μΩ-■, as shown in the graph of 422 plane growth in FIG. As a result, the magnetic permeability falls within the range of 1750 to 400, while the frequency at the time of 6 dB deterioration is IMHz to 60 M) (z
(See graphs of 422-plane growth in Figures 1 and 3, respectively).

In addition, when the crystal grain size falls within the range of 520 to 570,
The electrical resistivity is in the range of 90 to 100 μΩ-■, the magnetic permeability is 850 to 1150, and 5 MHz
The deterioration at is in the range of 6 to 3 ds. In addition, 22
When the 0-plane growth is performed, the electrical efficiency is in the range of 68.5 to 96 μΩ-■, as shown in the graph of the 220-plane growth in FIG. As a result, the magnetic permeability is within the range of 3100 or less, while the frequency at the time of 6 dn deterioration is 2.6M.
It is taken in the range of Hz to 15 MHz (see graphs of 220-plane growth in FIGS. 1 and 3, respectively).

(Example) The structure of the present invention will be described in detail below based on an example shown in the drawings.

FIG. 4 shows a perspective view of an embodiment of the magnetic head.

This magnetic head has a pair of substrates 1^, 1B as S i 0
They are butt-jointed with a spacer (not shown) made of a low magnetic permeability material such as No. A thin film 4 of ferromagnetic metal is formed, and a magnetic gap g is formed by this thin metal film 4. Note that the boards IA and 1B are usually 5
Ferromagnetic oxides such as ferrite are used when the device is intended for use up to a high frequency range of around 10 MHz, but ceramics etc. A non-magnetic material is used.

The ferromagnetic metal thin film 4 has a rectangular or trapezoidal track eraser 13 which is perforated in a direction perpendicular to the tape sliding contact surface 5 on the gap facing surface 3 parallel to the magnetic gap g. 1
It is formed on the wall surface 6 by a known vacuum thin film forming technique so as to have a uniform film thickness along the ridgeline formed by the gap facing surface 3 and the side wall surface 6. Therefore, the film thickness of 8M4 becomes thinner toward the bottom of the track groove 13, that is, in the tape sliding direction. However, this metal thin film 4
Since the necessary location is near the gap facing surface 3 forming the gap g, that is, near the surface of the track groove 1°3, the present invention shows that even if the location away from the gap g becomes narrow, there will not be much problem in the output characteristics. This has been confirmed through experiments by researchers and others.

In addition, when a ferromagnetic oxide is used for the substrate 1, the exposed portion of the ferromagnetic metal thin WA4 should be in an area that is equal to or larger than the width of the tape sliding contact surface 5 and narrower than the entire chip width W1, preferably the tape sliding contact surface. 5 and is suppressed to about 173 or less of the width of the shoulder portion 11. At this time, in the back core portion 10, the area where the cores IA and 1B are directly abutted against each other increases, and the effect of reducing the magnetic resistance appears conspicuously.

In addition, the grain size of the crystal grains 20 of the metal thin film 4 varies depending on the composition metal, but generally it is 300 to 700 when grown on 422 planes.
520 ~ 5, preferably for standard Sendust alloy
It is adjusted to a range of 70 people, most preferably about 570 people. Further, the crystal grain size is adjusted to 200 to 330 for 220-plane growth, and 270 to 330 for 5 MHz. There are various methods for adjusting the grain size of the crystal grains 20, as described below, but generally speaking, when trying to form a predetermined track width with a single layer, the substrate temperature rises during sputtering. It has a tendency to become grainy, which is difficult to control, and also causes the problem of eddy current loss due to an increase in J model. Therefore, -5 per M41
Multilayer II consisting of MI'J of ~6 μm! A non-magnetic material layer 21 is usually formed between each of the six pins 141 to prevent eddy current loss.

On the other hand, on the opposite side of the side wall surface 6 on which the thin film 4 is formed, a four part 8 is formed adjacently for regulating the track width of the magnetic gap g and suppressing the occurrence of a pseudo gap.
Oxidized glass 15 and fused glass 16 as non-magnetic materials
is melt-filled.

In the magnetic head of this embodiment, a magnetic herad chip is formed by slicing a block constructed by joining a pair of substrates 1 so as to have a predetermined azimuth angle.

Further, in the magnetic head of the present invention, the front core portion 9 near the tape sliding surface 5 and the back core portion 10 other than that have different chip widths, for example, a convex type as shown in FIG. Although not shown, it is formed into a trapezoid or L shape, and is designed to reduce the magnetic resistance of the back core portion 10.

Although the above-mentioned embodiment is one of the preferred embodiments, it is not limited thereto, and various modifications can be made without departing from the gist of the present invention. The composition is not limited to the standard Sendust alloy, but may be made of other ferromagnetic metals, and the shape itself does not have to be such that the front core part is smaller than the back core part as in this example. The shape of the groove and the direction in which the thin film is formed can be changed as appropriate, and are not limited to those described above.

Next, the manufacturing process of the magnetic head shown in FIG.
3. First, a large number of rectangular or trapezoidal track grooves 13 with a surface symmetrical shape extending toward the slope direction and the depth direction are formed at a predetermined pitch on the substrate 1. Figure 5(a)]. Next, this substrate I is divided into two parts along a plane perpendicular to the aforementioned depth direction to form a pair of substrates 1^ and 1B [Fig. 5(b)].
Then, these are washed and a ferromagnetic metal magnetic Fi [4] is formed using vacuum thin film formation technology [Figure 5(c)]
Generally, the magnetic thin film 4 is formed by sputtering a ferromagnetic metal such as Sendust alloy. This film is formed with the target facing the gap facing surface 3 so that the angle with respect to the target is approximately 45°. The pair of substrates 1^, 1B are placed facing a target and sputtered so that thin films are formed on opposite sidewall surfaces. That is, one substrate 1^ and the other substrate 1B are arranged in opposite directions with respect to the target so that the metal thin film [4 is formed on the left side wall surface and the right side wall surface of the same track groove 13, respectively. According to this method, the thin film 4 of ferromagnetic metal is formed so that the thickness becomes gradually thinner in the tape sliding direction, but it can be easily formed to a predetermined film thickness in the gap width direction, and A film having a constant thickness can be formed in the depth direction. The metal thin film 4 is required in the vicinity of the gap facing surface 3 forming the gap g, that is, on the surface of the track groove 13, so that even if the part away from the gap g becomes narrow, there is no problem in the output characteristics. Usually metal thin IT
! A4 is made of several layers of ferromagnetic metal, or is made of ferromagnetic metal.
As shown in the figure, the track width is formed by alternately depositing ferromagnetic metal 41 and nonmagnetic material 21, or by a single magnetic film to form a track width of about 20 μm+α. The grain size of the crystal grains 20 of the thin film metal in each layer 41 is 300 to 700 in 422-plane growth, preferably standard Sendust alloy (9.6% Si, 5.4% AI).
, residual Fe), it is adjusted to 520 to 570 people, and most preferably about 570 people in the case of sendust alloy. This control of the grain size can be achieved, for example, by sputtering at a rate of about 400 sputters/11 inches at a high temperature in an argon gas atmosphere when using standard Sendust Heili as a target. In addition, since sputtering takes a long time, the substrate temperature rises during that time, and even though it was initially set at around 200°C, it rose to over 300°C, and the intention was to grow the crystal with 220 planes, but instead it grew with 422 planes. Something like that happens. Therefore, it is necessary to perform sputtering intermittently to cool the substrate and to monitor the substrate temperature sufficiently.Normally, when the substrate temperature exceeds 300°C, the crystal grows in 422 planes, and below 300°C, the crystal grows in 222 planes.
There will be 0-sided growth. Also, if the temperature gets too high,
The crystals grow too much, the eddy current loss becomes too large, and the characteristics of the head deteriorate.

Therefore, the metal Fl film 4 is sputtered to a total film thickness of 5 to 6 μm per layer by repeatedly suspending sputtering and cooling.
The grain size growth of crystal grain 20 is 422 plane growth and the above-mentioned 300 ~
It is designed to limit the number of people to 700 people. It is also possible to alternately form a ferromagnetic metal and a non-magnetic material with a thickness of several tens of nanometers, and interrupt crystal growth with the non-magnetic material layer to keep the grain size within a certain range.

In addition, when the crystal growth is 220 planes, the crystal grain size is set to 200.
When the number of grains is 330, there is not much difference in magnetic permeability μ compared to the case of 422-plane growth, and since the temperature is low, the grain size can be easily adjusted to be small. Especially for 5 MHz, it is 270~3
In the range of 30 people, the decrease in magnetic permeability μ is small and the eddy current loss is small. Further, in a head compatible with 10 MHz, it is preferable to make the grain size close to 200 mm in order to prevent characteristic deterioration particularly in a high frequency range.

Next, the track groove 13 is filled with high melting point glass 15 to protect the thin film 4 [Glass bonding FIG. 5(d)]
After that, the gap facing surface 3 and the tape sliding surface 5 are ground to a flat surface with a predetermined surface roughness. Grinding is usually done by lapping to give a mirror finish. Thereafter, a track regulating recess 8 for eliminating a false gap is ground next to the track groove 13 and along the groove 13. When the four parts 8 are ground, the track width formed by the metal thin film 4 is adjusted to a predetermined width. Thereafter, a winding groove 12 is formed on the gap facing surface 3 of one of the substrates 1^ (FIG. 5(e)), and this winding groove 12 regulates the depth dimension. Note that the winding groove 12 is not formed on the other substrate 1B. Next, a spacer 2 made of a non-magnetic material such as 5i02 is formed by sputtering on the gap-opposing surfaces of both substrates IA and 1B. ^, 1B with the metal thin M4 facing each other, and the above-mentioned four parts 8 for track regulation.
is filled with low melting point glass 16 and bonded [gap bonding FIG. 5(f)]. One substrate 1B is reversed so that the track grooves subjected to the same processing are overlapped, and then shifted in the groove width direction so that the left wall surface of one substrate 1^ and the right wall surface of the other substrate 1B face each other. At this time, the ferromagnetic metal thin film 4 exposed on the gap facing surface 3fl
Since a gap g is formed between the side edges of the metal thin film 4
Accurate alignment is required so that the two faces face each other. After the gap bonding described above, the tape sliding surface 5 is cylindrically ground to finish the tape sliding surface 5 into a curved surface [FIG. 5(g)].

Next, the magnetic gap g takes a predetermined azimuth angle with respect to the tape sliding direction, and the front core part 9 is first formed and a groove is machined to obtain the tape sliding width. Grooves are formed on both sides of 5. This width corresponds to the width and depth of the shoulder. Thereafter, the substrate is sliced from the outside of the substrate and a large number of magnetic head chips are cut out [FIG. 5(h)]. After that, it is installed on the support head base after inspection, and the sliding surface is finished for better conformability in the track direction, and then the wire is wound.
Figure (i)].

(Effects of the Invention) As is clear from the above description, the magnetic head of the present invention has a crystal grain size of 300 to 7 when the metal thin film is grown on 422 planes.
00 people, preferably from 520 for standard Sendust alloy
570 and 220-plane growth, it is in the range of 200 to 330, so it is possible to prevent a large decrease in #J high frequency band while keeping the magnetic permeability within the practical range.0 For example, when using a standard Sendust alloy, When the grain size is in the range of 520 to 570 grains with 422 plane growth, the electrical resistivity is 90
It falls within the range of ~100μΩ-■, and the magnetic permeability at this time is 8
50-1150, and the degradation at 5 MHz is 6
~3 dn 0 Usually, the magnetic head is 100
If the lower limit of μ-f characteristics (frequency characteristics) at KHz falls within the range of 800 and the upper limit falls within the range of 1200, and the lower limit at 5 MHz falls within the range of 370, it can be used as a practical magnetic head, so compared to conventional ferrite magnetic heads. Frequency characteristics improve dramatically.

In addition, when the crystal growth is 220 planes, the crystal grain size is 20
When the number of grains is 0 to 330, there is not much difference in magnetic permeability μ compared to the case of 422-plane growth, and since the temperature is low, the grain size can be easily adjusted to be small. Especially for 5MH2 compatible 270-33
In the range of 0, the decrease in magnetic permeability μ is small and the eddy current loss is small. Further, in a head compatible with 10 MHz, it is preferable to make the grain size close to 200 mm in order to prevent characteristic deterioration particularly in a high frequency range.

Therefore, the magnetic head of the present invention has frequency characteristics such that the initial permeability is large and its decrease in the high frequency range is small.

[Brief explanation of the drawing]

Figure 1 is a graph showing the relationship between electrical resistivity and initial magnetic permeability in a standard Sendust alloy when grown on 422 planes and 220 planes, and Figure 2 is a graph showing the relationship between grain size and electrical resistivity in the same standard Sendust alloy. Graph showing the relationship between
The figure also shows the electrical resistivity and 6
Graph showing the relationship between the frequency at the time of ds and 3 dn attenuation, FIG. 4 is a perspective view showing an embodiment of the magnetic head, and FIG.
Figures (a) to (i) are processing flow diagrams of the same magnetic head. FIG. 6 is an enlarged sectional view showing an example of a metal thin film, and FIG. 7 is an enlarged sectional view of a metal thin film portion of a conventional magnetic head. DESCRIPTION OF SYMBOLS 1...Substrate, 4...Ferromagnetic metal thin film, 6...Side wall surface/thin film forming surface, 13...Track structure, 20...Crystal grain. Figure 2 Figure 3 F (Ffl-cm) Figure M7 Height

Claims (3)

[Claims] (1) In a magnetic head in which a thin film of ferromagnetic metal is formed on a pair of substrates constituting a core block by butt joining, and a magnetic gap is formed between the thin metal films, the crystal grains of the thin film of ferromagnetic metal A magnetic head characterized in that the diameter is in the range of 300 to 700 Å when grown on 422 planes. (2) The magnetic head according to claim 1, wherein when the thin film metal is a sendust alloy, the crystal grain size is set in a range of 520 to 570 Å when grown on 422 planes. (3) In a magnetic head in which a ferromagnetic metal thin film is formed on a pair of substrates constituting a core block by butt-jointing, and a magnetic gap is formed between the metal thin films, the crystals of the ferromagnetic metal thin film are formed. The grain size is 2 for 220 plane growth.
A magnetic head characterized in that the magnetic head has a thickness in the range of 00 to 330 Å.