JPH04205805A - Magnetic head - Google Patents

Abstract

PURPOSE:To enable deterioration of recording characteristics and C/N characteristics to be reduced by joining one magnetic core where a high- saturation magnetic flux density soft magnetic thin film is provided on a surface where a magnetic gap is formed and the other magnetic core consisting of a single crystal Mn-Zn ferrite where SnO2 is subjected to solid solution through a gap material. CONSTITUTION:A high-saturation magnetic flux density soft magnetic thin film 1 is formed on a gap surface of a magnetic core 11 and a magnetic core 2 where a coil-winding window 15 is formed is constituted by a single-crystal Mn-Zn ferrite where SnO2 is subjected to solid solution. Also, a gap 3 is formed through a non-magnetic material 13 consisting of glass or SiO2 between the magnetic cores 2 and 11 and a high-saturation magnetic flux density soft magnetic thin film 1. Then, a track width regulating groove is formed from a front gap part to a back gap part, a glass 14 is filled at the part, and the high saturation magnetic flux density soft magnetic thin film 1 exists not only near a gap but also along a part of the track width regulating groove, thus enabling a sliding noise to be reduced and C/N characteristics to be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is applicable to high-density magnetic recording media with high coercive force used in video tape recorders (VTRs), digital audio recorders (DATs), floppy disks (FDDs), etc. Conventional technology related to magnetic heads suitable for recording and reproducing information For high-density magnetic recording and reproduction, the coercive force of the recording medium should be increased, and the saturation magnetic flux density of the magnetic head should be increased. Although it is generally known that ferrite material ζ is currently the mainstream material for magnetic heads,
Its saturation magnetic flux density is about 5000 Gauss,
If used with metal tapes that exhibit a high coercive force of 10,000e or more, magnetic saturation will occur and recording will not be performed adequately.
Therefore, even though magnetic heads using Sendust alloy, CO-based amorphous film, etc., which have a higher saturation magnetic flux density than ferrite materials, have been put into practical use, the structure of the magnetic head (as shown in Figure 3, the two magnetic cores 11 are Mn - This is a MIG (metal-in-gap) magnetic head made of Zn ferrite and composed of a soft magnetic film fi12 and a non-magnetic gap material 13 on both sides near the magnetic gap, and its manufacturing method is almost the same as that of conventional ferrite heads. Since they are the same, much research is being carried out.In the same figure, 14 is a winding window for regulating the track width, and 15 is a winding window.

Problems to be Solved by the Invention However, with the conventional MIG type magnetic head,
At the boundary between the soft magnetic thin film 12 and the ferrite core 11,
A magnetically degraded layer is formed in this portion due to the reaction. If this magnetic deterioration layer is parallel to the gap plane, it acts as a pseudo gap and generates a pseudo signal (Journal of the Japan Society of Applied Magnetics Vol. 1.11. No.
2.1987, pp. 105-108).

When joining magnetic cores, a method called glass fusion is generally used, but in that case heat treatment at 500°C or higher is required. At this time, a reaction occurs at the boundary between the ferrite core and the above-mentioned soft magnetic thin film, and even though a very magnetically degraded layer is formed, the boundary between the two acts as a pseudo gap because it is parallel to the gap surface, and the head When the ferrite core is exposed near the gap, it also causes problems such as increased sliding noise and deterioration of C/N characteristics. The present invention solves the above-mentioned problems even though they are fatal to systems such as the above. In order to achieve the above object, the magnetic head of the present invention has one magnetic core provided with a high saturation magnetic flux density soft magnetic thin film on the magnetic gap forming surface, and the other magnetic core made of single crystal Mn-Zn ferrite containing 5nu2 as a solid solution. The magnetic deterioration layer is present only on one side, and the magnetic core is a single crystal with SnO2 dissolved in solid solution. Composed of Mn-Zn ferrite to suppress sliding noise.

EMBODIMENTS A magnetic head according to an embodiment of the present invention will now be described with reference to the drawings (Embodiment 1) First, an embodiment of the structure of a magnetic head will be described. FIG. 1 shows an example of a magnetic head according to the present invention, and FIG. 1(a) is a perspective view of the magnetic head according to the present invention. In the figure, a magnetic core 11 is made of an oxide magnetic material such as Mn-Zn ferrite. A high saturation magnetic flux density soft magnetic thin film 1 is formed on the gap surface of the magnetic core 11. The magnetic core 2 in which the winding window 15 is formed is made of single crystal Mn--Zn ferrite containing 5n02 as a solid solution.

Also, between the magnetic cores 2 and 11 and the high saturation magnetic flux density soft magnetic thin film 1, a non-magnetic material 13 made of glass or 5i02, etc.
A gap 3 is formed through the L track width regulating groove from the front gap portion to the pack gap portion. Fig. 1(b) is an enlarged view of the sliding surface of the magnetic head of the present invention near the gap. The density soft magnetic thin film 1 is made by laminating, for example, 100 layers of CoNbZr (200) 3 and CoNbZ rN (200) 4 [hereinafter referred to as (CoNbZ r/CoNb)].
Even if a so-called superstructure nitride film with a film thickness of 4 μm is used, the saturation magnetic flux density of this superstructure nitride film is l.

There are various types of magnetic head structures other than the one shown in FIG. 1, an example of which is shown in FIG. 2.

In FIG. 2(a), the high saturation magnetic flux density soft magnetic thin film 1 is formed only in the gap portion, and the other structure is the same as that in FIG. 1. In FIG. 2(b), the track width regulating groove is formed only in the front gap, and the high saturation magnetic flux density soft magnetic thin film 1 is also present only in the vicinity of the gap. The example shown here is an example of a magnetic head configuration.
The essence of the present invention is to form a high saturation magnetic flux density soft magnetic thin film 1 only on the gap forming surface of the magnetic core 11 on one side;
The magnetic core 2 on which the high saturation magnetic flux density soft magnetic thin film 1 is not formed is composed of single crystal Mn-Zn ferrite containing 5not as a solid solution. Regarding the shape and the like, there are many configurations other than those shown here.Next, the results of measurement of the electromagnetic conversion characteristics of the magnetic head of the present invention will be shown.

First, a high saturation magnetic flux density soft magnetic thin film 1 shown in FIG.
An example will be shown in which a material containing o as a main component is used.

Co-(Nb,
Zr, Ta) (200 people) and Co-(Nb,
Zr, Ta)-N (200 people) and 100 layers each.
Using a superstructured thin film with a film thickness of 4 μm, the gap length of the nine magnetic heads is 0.3 μm, and the track width is 20 μm.
Use a drum tester to measure (at a relative speed of 5.8 m/s between the head and tape. The coercive force of the tape is 1550.
The amplitude of the waviness in the frequency characteristics of heads using various high saturation magnetic flux density soft magnetic thin films was measured using Oersted. The results are shown in Table 1.

(Hereinafter, blank space) In the column of waviness amplitude in the upper table of Table 1, (a) is the magnetic head of the present invention, and for the case where a high saturation magnetic flux density soft magnetic thin film is formed only on one magnetic core (b) ) shows the amplitude of waviness in the frequency characteristics of the magnetic head when soft magnetic thin films are formed on both magnetic cores. Waviness amplitude UIMHz ~ 1
What is the value of the largest amplitude at 0MHz?
= In the case of (a), the average value of the amplitude of the waviness is approximately 1.3 dB
On the other hand, in the case of (b), it was about 2.9 dB. Although it is possible to reduce the negative effects caused by the equipment gap compared to the case where a soft magnetic thin film is formed, recording characteristics deteriorate when a high saturation magnetic flux density soft magnetic thin film is formed only on one side of the magnetic core. Therefore, we compared the recording characteristics when a high saturation magnetic flux density soft magnetic thin film was formed only on one side and when it was formed on both sides of the magnetic core by varying the saturation magnetic flux density of the high saturation magnetic flux density soft magnetic thin film. The measurements were carried out under the same conditions as above. The gap length of the magnetic head was 0.28 to 0.30 μm. The reproducing head was a ferrite head with a gap length of 0.25 μm. The measurement frequency was 1°0 MHz. The saturation magnetic flux density of the high saturation magnetic flux density soft magnetic thin film is (1)1.
OT, (2) 1.2T, (3) 1.3T, (4) 1
゜ 4T, (5)1. The experiment was conducted on 5T.The number of samples was 3 for each, and the average value is shown.
Now measure ζ, coercive force (A) = 7500e,
(B) = 170006 The tape of 17000e is one of the metal tapes currently on the market with the highest coercive force, and the results are shown in Figure 4. Although the characteristics are shown when compared with the standard (OdB) when a high saturation magnetic flux density soft magnetic thin film is formed on both sides of the magnetic core, first of all, in the case of (A), both (1) to (5) are satisfied. There is no difference between the case where a high saturation magnetic flux density soft magnetic thin film is formed on the magnetic core and the case where it is formed only on one side of the core.9 In other words, the coercive force is 7500.
For a recording medium of about E, simply forming a material with a saturation magnetic flux density of 1.0T (Sendust was used here) on one side of the magnetic core will produce the same recording characteristics as when forming it on both magnetic cores of L. Next, (B)
In the case of (1), it was clearly found that the magnetic head with a high saturation magnetic flux density soft magnetic thin film formed on both cores had better recording characteristics. It has been found that there is almost no difference between forming a high saturation magnetic flux density soft magnetic thin film on only one core and forming it on both cores.
From this, we know that when the coercive force increases to about 17000e, recording becomes insufficient with the Sendust material with a saturation magnetic flux density of 1.0T, and a material with a saturation magnetic flux density of 1.2T or more is required. If the saturation magnetic flux density of the density soft magnetic thin film is 1°2T or more, by forming a high saturation magnetic flux density soft magnetic thin film only on one side of the magnetic core, the current amount and coercive force of the metal tape on both sides can be increased. It was found that a MIG type magnetic head with recording characteristics comparable to those of a magnetic head with a high saturation magnetic flux density soft magnetic thin film formed in the magnetic core was obtained.9 The saturation magnetic flux density was 1.2T or higher, and heat treatment at 500℃ or higher was used. As a material exhibiting soft magnetic properties, a material represented by the general formula CoM in the ζ table and its nitride (-general formula CoMN) have a laminated structure at least at the time of thin film production (hereinafter referred to as C).

It is expressed as M/CoMN. Here, M is metal light (iN is nitrogen), and so-called superstructured CO-based compositionally modulated nitride alloy films are mentioned. Regarding the composition of the alloy film, lt and co are atoms in order to increase the saturation magnetic flux density to 1.2 T or more. The ratio should be 80% or more, and M is Nb to ensure the specified soft magnetic properties.
, Zr, Ta, Hf, Ti, Mo, and W, and the atomic ratio is 5% to 20%4. Also, the thickness per layer is 1500 Å or less.
An example of these materials that can obtain the desired soft magnetic properties is 1icoNbZr/CoN.
bZrN, CoTaZr/CoTaZrN, CoNbZ
rTa/CoNbZrTaN, CoMoZr/CoMo
ZrN, CoNbMoor/CoNbMoZrN, Co
T1Nb/CoTiNbN, CoWNb/CoWNbN
etc. Among these, especially Co N b Z r /
C.

NbZrN, CoTaZr'/CoTaZrN, CoN
bZ rTa/Co'NbZ rTaN is desirable L%
In this example, an example of a soft magnetic material containing Co as a main component is shown as a high saturation magnetic flux density soft magnetic thin film (the present invention is not limited to this). , similar effects can be obtained as long as the film exhibits predetermined soft magnetic properties.Furthermore, the film thickness may vary depending on the intended use of the magnetic head. The measurement method is as shown in Figure 5. The measurement method is as shown in Figure 5.The measurement method is as shown in Figure 5. The relationship between changes in the protruding state of the head and sliding noise was also investigated, and the results are shown in Table 2.

Table 2 From Table 2, the magnetic head of this embodiment has reduced sliding noise by about 2 dB compared to the conventional magnetic head.Compared with the ferrite head, the difference is about 8 dB. The reason why the sliding noise is lower than that of other magnetic heads. This is thought to be due to the fact that it is composed of crystalline Mn-Zn ferrite.Not only does it have lower noise than ferrite heads, but it also has superior results compared to conventional magnetic heads. Now, we have examined the relationship between the head-tape interface condition and sliding noise.In a conventional magnetic head, the sliding noise level changes by about 4 to 8 dB depending on the interface condition. On the other hand, in the magnetic head of this example, the change was small, about 2 to 3 dB.This fact also proves the superiority of the head of this example against sliding noise.9 (Example 2) Figure 1 An example is shown in which a high saturation magnetic flux density soft magnetic material containing Fe as a main component is used for the high saturation magnetic flux density soft magnetic thin film 1 shown. In this example, FeNbZr (
250 each of FeNbZrN (100 people) and FeNbZrN (100 people)
This is an example of a magnetic head in which a high saturation magnetic flux density soft magnetic thin film with a film thickness of 5 μm is formed. Here, the saturation magnetic flux density of the high saturation magnetic flux density soft magnetic thin film is 1.5 Tesla.
Regarding the electromagnetic conversion characteristics, the results of measurements similar to those in Example 1 are shown in Table 3 below.

(Hereinafter, blank space) Table 3 In Table 3, & Fe −(Ti, Nb, Z
r, Ta, Mn) (100 people) and Fe-(
Ti, Nb, Zr, Ta, Mn) -N
(100 people) and 200 layers each), film thickness is 4μ
(c) A magnetic head L in which a soft magnetic thin film with a high saturation magnetic flux density of m is formed only on one side of the magnetic core. (d) The amplitude of the waviness in the frequency characteristics of a magnetic head formed on both magnetic cores is shown. The average amplitude of the waviness of the frequency characteristic is 1.3 dB in case (c), while it is approximately 2 dB in case (d).
．． 9 dB, and it is possible to reduce the amplitude of waviness by forming a high saturation magnetic flux density soft magnetic thin film only on one side of the magnetic core, regardless of the saturation magnetic flux density of the high saturation magnetic flux density soft magnetic thin film. Regarding recording characteristics, coercive force (A) 7500e and (B
) Using a 17000e recording medium, the saturation magnetic flux density of the soft magnetic thin film is (1) 1.0T, (2) 1.2T, (3)
1. Experiments were conducted on materials of 4T, (4) 1°5T, and (5) 1.6T.

Figure 6 shows the results. Same as when a Co-based composition-modulated nitride alloy film is used as a high saturation magnetic flux density soft magnetic thin film.As for +;= (A), there is almost no difference between (1) to (5), and only one magnetic core has high saturation. Recording characteristics do not deteriorate even if a magnetic flux density soft magnetic thin film is formed ζ - On the other hand, regarding the high coercive force medium in (B) ζ In (1), a high saturation magnetic flux density soft magnetic thin film is formed only on one magnetic core. It was confirmed that there is almost no difference in terms of force length (2) to (5), where the recording properties are inferior to when magnetic cores are formed on both sides of the magnetic core.When the saturation magnetic flux density is 1.2T or higher and the temperature is 500℃ or higher, An example of a material containing Fe as a main component that exhibits soft magnetic properties even after heat treatment is a laminated structure of FeM film and FeMN film (hereinafter referred to as F
It is expressed as eM/FeMN. Here, M is a dead metal, N is nitrogen, and the superstructured film has 70% or more in atomic ratio in order to increase the saturation magnetic flux density to 1.2T or more. is Nb, Zr5Ta, Ti to ensure the specified soft magnetic properties.
5Cr, Hf, Mo, W, Mn, Re
, Ru, and the atomic ratio may be 5% or more and 30% or less. Among these materials, the special materials FeNb/FeNbN, Fea
r/FeZrN.

FeTi/FeTiN, FeTi/FeTiN.

FeNbZr/FeNbZrN, FeNbTa/F
eNbTaN, 'FeNbTi/FeNbTiN,
FeZrTi/FeZrTiN, FeZrTi
/FeZrTiN, FeZrMn/FeZrMnN
, FeNbMn/FeNbMnN, etc. are preferable. Also, the thickness per layer may be within a range that maintains the soft magnetic properties, and the film thickness of the high saturation magnetic flux density soft magnetic thin M1 may be changed depending on the use of the head. Similar to the magnetic head using the Co-based composition-modulated nitride alloy film shown in Example 1, we conducted a comparative study on the level of sliding noise.The measurement method was the same as in Example 1. It is shown in Table 4.

(The following is a margin) The results in Table 4 show almost the same tendency as in the case of a magnetic head using a Co-based composition-modulated nitride alloy film, and the sliding noise is reduced by about 1°5 dB compared to a conventional magnetic head. We were also able to confirm the superiority of the magnetic head of this example in terms of the relationship between changes in the interface state between the magnetic head and tape and sliding noise. As a method for producing a soft magnetic thin film having a high saturation magnetic flux density, for example, it can be obtained by sputtering, using CoM or FeM as a target, and periodically mixing nitrogen gas with Ar gas at a predetermined ratio.

Effects of the Invention The present invention provides magnetic heads for VTRs, DATs, and FDDs with smaller pseudo signals and lower C/N noise than conventional ones.
It is possible to obtain a MIG type magnetic head with excellent characteristics, and the manufacturing process of the magnetic head according to the present invention is simple, and a low cost MIG type magnetic head can be obtained, thereby providing a magnetic head with extremely high practical value. is possible

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1(a) is a perspective view of an embodiment of the magnetic head of the present invention. FIG. 1(b) is an enlarged view of the vicinity of the gap on the sliding surface of the magnetic head. FIG. ) and (b) are perspective views of other embodiments of the magnetic head. FIG. 3 is a perspective view of the conventional magnetic head. FIGS. 4 and 6 show the recording characteristics of the magnetic head of the present invention and the conventional magnetic head. Comparison @ Figure 5 is a model diagram showing a method for measuring sliding noise. 1... High saturation magnetic flux density soft magnetic thin [2, 11... Magnetic core, 13... Non-magnetic material. Name of agent: Patent attorney Akira Okaji and 2 others Figure 1 Figure 4 Museum 81 East! Liao (Bs) Figure 5 Figure 6

Claims (1)

[Scope of Claims] (1) One magnetic core with a high saturation magnetic flux density soft magnetic thin film provided on the magnetic gap forming surface and the other magnetic core made of single-crystal Mn-Zn ferrite with SnO_2 as a solid solution are made of a non-magnetic material. A magnetic head characterized in that it is bonded via. (2) High saturation magnetic flux density The saturation magnetic flux density of the soft magnetic thin film is 1.
The magnetic head according to claim 1, characterized in that the magnetic head has a magnetic flux of 2 Tesla or more. (3) The high saturation magnetic flux density soft magnetic thin film has a structure in which a material represented by CoaMb and its nitride are alternately laminated, or the nitrogen composition is modulated in the film thickness direction. A magnetic head according to claim (1). Here, M is Nb, Ta, Zr, Hf, Ti, Mo, W
It consists of one or more of the following, a and b represent an atomic ratio, and satisfy the following formula. 0.80≦a≦0.95 0.05≦b≦0.20 a+b=1.0 (4) The high saturation magnetic flux density soft magnetic thin film is made by alternately laminating the material represented by FeaMb and its nitride. 2. The magnetic head according to claim 1, wherein the magnetic head has a structure in which the composition of nitrogen is modulated in the film thickness direction. Here, M is Nb, Ta, Zr, Hf, Ti, Mo, C
Consisting of one or more of r, W, Mn, Re, Ru, a
, b represent the atomic ratio and satisfy the following formula. 0.70≦a≦0.95 0.05≦b≦0.30 a+b=1.0