JPH0469806A - Magnetic head - Google Patents

Abstract

PURPOSE:To reduce the influence of distortion due to a thermal expansion coefficient by joining ferrite cores with a metallic layer by low-temperature treatment. CONSTITUTION:Layers 3 made of Ag, Pd, or Pt are formed on junction surfaces 1a and 2a by vapor-deposition, sputtering, or the like. A pair of ferriter cores 1 and 2 are so butted that mutual layers 3 face each other, and they are subjected to heat treatment in a vacuum furnace at <=400C, and they are joined into one body by mutual diffusion of layers 3. The distortion due to the thermal expansion coefficient is reduced because of junction at a low temperature, and a head having high weather proof and high reliability is obtained because of the use of a noble metal like Ag, Pd, or Pt as the junction material.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a magnetic head used in a VTR or the like.

[Summary of the Invention] The present invention provides a magnetic spatula l'' used for VTR, etc., in which a layer of Ag, Pd or ))t is formed on the bonding surface.
High reliability of the magnetic head is achieved by constructing a pair of magnetic cores by 34 mm bonding to the mutual diffusion of the A, g, r) d or PL layers.

Furthermore, the present invention provides the following features: -] A,
By forming a base film on the Pd or Pt layer, the bonding strength is further increased and the reliability of the magnetic field is increased.

Furthermore, the present invention provides a structure in which a magnetic head is provided with a film having optical properties different from those of the magnetic core at the interface with the bonding surface of the magnetic core. In addition to improving reliability, the magnetic gap length can be easily detected by optical means.

[Prior Art] In magnetic heads for VTRs and the like that require durability, it is desirable to use the glass bonding method for bonding points such as magnetic gaps. The reason for this is that glass is chemically stable, can be cleaned with an organic solvent, and has the advantage of being able to form a strong bond.

In addition to ferrite magnetic heads, high saturation magnetic flux density B is used in the magnetic gap part of the ferrite core as a magnetic head for VTRs.
A magnetic head called a metal-in-gap head that has a metal magnetic film of s and enables saturation recording on high coercive force tape (metal tape, vapor-deposited tape), or a so-called laminate head made by laminating multiple metal magnetic films. etc. have been proposed.

[Problem to be solved by the invention]

By the way, the above-mentioned glass bonding method applies distortion due to the coefficient of thermal expansion to the metal magnetic film and ferrite due to the high temperature of 550°C or higher (that is, glass below 550"C lacks reliability), which affects the magnetic properties. This was causing deterioration and cracking.

Furthermore, for metal-in-gap heads, laminate heads, etc. that use an amorphous alloy as the metal magnetic film, if the above glass bonding method is used, heat treatment must be performed at a temperature higher than the crystallization temperature of the amorphous alloy (approximately 500°C). However, a glass bonding method cannot be used because of the problem of deterioration of head characteristics due to crystallization.

Furthermore, in the case of floppy disk drives and composite heads for hard disks that require glass bonding several times, high melting point glass must be used for primary fusing and low melting point glass for secondary fusing. Therefore, they were forced to use unreliable low melting point glass.

Furthermore, in laminated heads and the like, there are parts other than the magnetic gap that require bonding.

In particular, when an amorphous alloy is used as a metal magnetic film, water glass or an organic adhesive has been used as a bonding agent since high melting point glass cannot be used as mentioned above. However, these bonding agents have problems in terms of strength and weather resistance, and significantly deteriorate the reliability of the magnetic head.

In view of the above-mentioned points, the present invention has been achieved without deteriorating the head characteristics, weather resistance, etc. This provides a strongly bonded and highly reliable magnetic head.

[Means to solve the problem]

The magnetic electrode of the present invention has Ag, Pd or Pt on the bonding surface.
A pair of magnetic cores 1) and (2) on which an O layer (3) is formed is
It is constructed by bonding by interdiffusion of g, Pd or Pt0 layers (3).

Further, the present invention provides the magnetic head described in item 1 above, which includes:
It is constructed by having a base film (5) on a layer (3) of Ag, Pd or PL.

Furthermore, in the magnetic head according to the above item 1 or 2, the present invention provides a film (7) having optical properties different from those of the magnetic core (1) (2) at the interface with the bonding surface of the magnetic core (102).
).

[Effect]

In the first invention, a pair of magnetic cores (1) and (2) are provided.
) is bonded by mutual diffusion of the layer (3) of Ag, Pd, or Pt formed on the bonding surface, so that a strong bond can be achieved by low-temperature treatment. Therefore, the influence of strain caused by the thermal expansion coefficient is suppressed, and for example, the amorphous alloy 11
! (11) When applied to metal-in-gear head, laminated head, etc.
11) Crystallization does not occur and good head and throat characteristics are obtained. Also, Ag, Pd.

Since it is bonded with PL precious metal, it also has excellent weather resistance.

In the second invention, the Ag, Pd or Pt0 layer (3)
Since the base layer M(5) is provided below, the adhesion strength of this layer (3) to the magnetic cores (1) and (2) is improved, and a more reliable magnetic head can be obtained.

Furthermore, in the third invention, magnetic cores (1) and (2)
) is provided with a film (7) having optical properties different from those of the magnetic cores (1) and (2), so that the magnetic gap length LP can be easily detected by optical means.

〔Example〕

Hereinafter, seven embodiments of the magnetic field according to the present invention will be described with reference to the drawings.

The magnetic head according to the present invention is basically formed by depositing a layer of Ag, Pd or (iPt) on the required bonding surface (magnetic gamble part, other parts) of the magnetic head, and then subjecting it to low-temperature heat treatment. The two layers are bonded together by interdiffusion of the layers.

Fig. 1 shows the case where it is applied to the throat of Flyrai +, and the manufacturing method of A is also explained.

In this example, in the first IA, Ag, A layer (3) of Pd or PI is deposited by vapor deposition, sputtering, or the like.

Next, as shown in FIG. 1B, a pair of ferrite cores (1) and (2) are butted together so that the layers (3) are in contact with each other, for example, at a pressure of 1.00 kgf/cm. Heat treatment is performed at 250°C for 11 hours using a vacuum furnace in an atmosphere on the order of 10'' Torr under a certain pressure, and the mutual layers (3) are bonded by phase 11 diffusion.
I stop.

Ag, Pd or Pt is non-magnetic, has a magnetic gap g, and is joined by
, constitutes a light head (4).

Here, the bonding conditions are bonding pressure IQkgf/(・
m2 or more, and the heat treatment temperature is 400° (less than 100°C, the heat treatment temperature is 400°).

Due to its nature, it is possible to bond with excellent bonding strength, weather resistance, etc. at a low temperature of 400°C or less.

2, a layer of Ag, Pd or i)t (
It is also possible to provide a two-layer structure by interposing a non-magnetic ground film (5) of Cr, Ti, Mo, etc. under each layer 3).

I=g is the gap length. Such configuration (7) '7
According to Elai 1 Het (6), the base film (5) has good adhesion to the ferrite cores (1) and (2), so the ferrite cores (1) and (2) and Ag, Pd or
t f7) The adhesive strength between the layers (3) increases and a stronger bond can be obtained.

Furthermore, as shown in Part 3, a knee 17 material forming a gap forming surface, that is, a ferrite material in this case, is added to the interface between the base film (5) and the ferrite cores (1) and (2). For example, Sin has different optical properties (for example, higher light transmittance, higher light absorption, etc.). It is also possible to form a three-layer structure by interposing a non-magnetic film (7) such as , SiO, Taz05, etc. SiO□, SiO, Taxes, etc. have high light transmittance. In the ferrite having such a structure (8), when light is applied to the sliding surface of the recording medium, the reflectance of the surfaces of the ferrite cores (1) and (2) and the surface of the film (7) is For example, with an optical microscope, the magnetic gap length I1g
can be easily detected.

The following Table I shows the anti-JJi force (kgf/shell 2) when ferrite cores (1) and (2) are joined as a joining layer (3) using 8e and d, respectively. However, 7, base film (5
) was used as Cr.

Table 1 The transverse rupture strength of the high melting point glass used for normal Heno-F gear knob joints is approximately 4.3 kgf/m+n2.

According to Table 1, the transverse rupture strength of Pcl and Ag is equal to or higher than that of conventional high melting point glass, and it is recognized that the bonding is strong. Incidentally, even if there is only one Pt, a transverse rupture strength of 10% can be obtained.

The fourth example is a case where the invention is applied to a metal-in-gap head. In this example, the metal magnetic film of magnetic cores (12) and (13) has a metal magnetic film (+, 1.) made of sendust, FeGaSi (Ru) alloy, or amorphous alloy on the gear knob part of the ferrite core (102). (11) C on each side
rA layer of Ag, Pd or Pt, e.g. Ag layer (3), is deposited through a base film such as Ti or Mo, e.g. Cr film (5), by f-deposition or sputtering 2, and the same bonding conditions as for the upper side are applied. [Metal in gap] Page 14)
Configure.

Here, as the metal-in-gap head (14),
When viewed from above, it can be configured as shown in FIGS. 5A and 5111JB. In the figure, (1) and (2) are ferrite cores, and (111) is, for example, FeGa51 (Ru
) alloy film, (11□) is, for example, sendust film, (15)
(14A) and (14B) indicate the entire metal-in-gap head.

In addition, a metal-in-gap head (1
6) has a metal magnetic film (11) between the metal magnetic film (11) constituting the magnetic gap forming surface of the magnetic core and the base film (5).
For example, S+02.1) has different optical characteristics from S+02.1). sio I
This is a case where a non-magnetic film (7) such as TazOs is interposed.

According to the Merrill-in-gap head" (14) with such a configuration, for example, since the bonding is performed at a temperature lower than the crystallization temperature of an amorphous alloy, even if an amorphous alloy film is used as the metal magnetic film (11), it will not crystallize. A highly reliable head that maintains good head characteristics and is firmly bonded can be obtained.

Further, as shown in FIG. 6, when forming a film (7) of SiO2, SiO, Taxes, etc. at the interface with the metal magnetic film (11), the magnetic gap is Long Lg can be easily detected.

FIGS. 7 and 8 show the case where the present invention is applied to a laminating head.

FIG. 7 shows a pair of laminate cores (22) and (23) in which a plurality of metal magnetic films (2I) are laminated to form a magnetic gap g, and to form a magnetic gap g.
(23), for example, Mn-Zn on both sides in the track width direction.
A nonmagnetic substrate (24) made of ferrite is arranged, and
Further, reinforcing members (25) made of the same material are arranged at both ends in the recording medium sliding direction. (27) is a glass material. In this example, the bonding portion (26) indicated by diagonal lines is bonded using the layer (3) of Ag, Pd, or Pt described above (possibly having a base film (5), a nonmagnetic film (11), etc.). do.

In the case of Fig. 8, the laminate cores (22), (23
) are arranged with nonmagnetic substrates (24) made of, for example, Mn--Zn ferrite on both sides of the track width direction.

In this example, the bonding portion (26) indicated by diagonal lines is bonded using the layer (3) of Ag, Pd, and Pt (which may have a base film (5), a nonmagnetic film (11), etc.). do.

In such laminate cores (28) and (29), for example, even if a laminate core made of an amorphous alloy film is used, the laminate cores are firmly bonded without crystallizing, and have good head characteristics and are weather resistant and reliable. A laminate head with high properties can be obtained.

As described above, according to this embodiment, since low-temperature bonding is possible, distortion caused by the coefficient of thermal expansion can be reduced. Particularly in metal-in-gap heads, laminate heads, etc. that use an amorphous alloy film, the heads can be joined without deteriorating (crystallizing) the amorphous alloy film.

Further, since noble metals such as Ag, Pd, and Pt are used as the bonding material, a head with high weather resistance and high reliability can be obtained.

Since the bonding is performed by mutual diffusion of Ag, Pd, and PL, a head with high bonding strength can be obtained. In addition, since low-temperature bonding is possible, it is possible to suppress the generation of pseudo gaps (reaction layers) that are a problem with metal-in-gap heads.

〔Effect of the invention〕

According to the magnetic heeling method of the present invention, by bonding using Ag, Pd, or PtO layers through low-temperature processing, the influence of distortion caused by the coefficient of thermal expansion is reduced compared to conventional high-melting point glass bonding, and the magnetic It does not cause deterioration of properties, cracks, etc.

In particular, in metal-in-gear heads and laminates using an amorphous alloy as a metal magnetic film, the head characteristics are not deteriorated by bonding at a low temperature below the crystallization temperature of the amorphous.

Since the bonding is performed by interdiffusion of Ag, Pd, or Pt layers, the bonding strength is high, and since the core layer is made of a so-called noble metal, the weather resistance is also excellent.

Furthermore, when a base film is formed under the Ag, Pd, or Pt layer, the adhesive strength between the magnetic core and the Ag, Pd, or Pt0 layer is further increased, and the bonding strength is further improved.

Furthermore, when forming a film called optical ↑A I ('') stomach on the interface between the magnetic core and the bonding surface, optical-1 stage t
, Koyo, Koyo brother Gokoshu, Ki Gear, and Buchou are detected.゛、
I can do it.

I am very happy to provide you with a high level of trust.

[Brief explanation of drawings]

FIG. 1 shows an example of the magnetic field according to the present invention. FIG. 2 g! Fig. 3 shows another example of the magnetic head 71 according to the present invention 6L;
Figures 5 and 1A and B are bottom views of the metal-in-gap head, and Figures 7 and 8 are perspective views of the magnetic head according to the present invention when it is applied to a laminate head. It is a diagram. (1), (2) are ferrite cores, (3) are A, g,
i) d or PI layer, (g) magnetic gap, (5)
(7) is a film that improves the magnetic core and optical properties (1), and (11) is a metal magnetic film. Figure 3 Nutanoshi Inya soft color -vF+ side view Figure 5! Figure 7 Figure 8

Claims (1)

[Claims] 1. A magnetic head in which a pair of magnetic cores each having a layer of Ag, Pd, or Pt formed on their bonding surfaces are bonded together by mutual diffusion of the layers. 2. Claim 1 comprising a base film on the layer of Ag, Pd or Pt.
The magnetic head described. 3. The magnetic head according to claim 1 or 2, further comprising a film having optical properties different from those of the magnetic core at the interface with the bonding surface of the magnetic core.