JP3165691B2 - Magnetic head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a magnetic head used for a VTR or the like.

[0002]

[Prior art]

In a VTR magnetic head or the like that requires durability, it is considered that a glass bonding method is preferable for a bonding portion such as a magnetic gap. The reason is that the glass is chemically stable, so that it can be washed with an organic solvent and has such advantages that a strong bonding can be obtained.

As a magnetic head for VTR, in addition to a ferrite magnetic head, a high saturation magnetic flux density
A magnetic head called a metal-in-gap head having a Bs metal magnetic film and capable of recording saturation on a high coercive force tape (metal tape, vapor-deposited tape), or a so-called laminate head formed by laminating a plurality of metal magnetic films Etc. have been proposed.

[0004]

[Problems to be solved by the invention]

By the way, the above glass bonding method has a high temperature of 550 ° C. or higher (that is, glass having a temperature of 550 ° C. or lower lacks reliability).
The strain caused by the coefficient of thermal expansion was given to the metal magnetic film and the ferrite, causing deterioration of the magnetic properties and cracking.

In a laminate head or the like using an amorphous alloy as the metal magnetic film, if the above glass bonding method is used, a heat treatment at a temperature higher than the crystallization temperature (about 500 ° C.) of the amorphous alloy is performed, This causes a problem of deterioration of the head characteristics due to the above, and the glass bonding method cannot be used.

Further, in a head for a floppy disk, a composite head for a hard disk, and the like that require several times of glass bonding, a high melting glass is not used for primary fusion and a low melting glass is used for secondary fusion. The use of unreliable low-melting glass.

[0007] Furthermore, in a laminating head or the like, there are places where joining is required even in a portion other than the magnetic gap. In particular, when an amorphous alloy is used as the 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 described above. However, these bonding agents have problems in strength and weather resistance,
This significantly deteriorated the reliability of the magnetic head.

The present invention has been made in view of the above circumstances, and provides a highly reliable magnetic head that is firmly joined without deteriorating head characteristics, weather resistance, and the like.

[0009]

[Means for Solving the Problems]

According to the present invention, in a magnetic head in which a pair of magnetic cores are joined via a gap material, the magnetic core comprises a laminated film of a non-magnetic film and a metal magnetic thin film, and faces the recording medium sliding surface in contact with the magnetic core. A non-magnetic member having a surface is arranged, and a magnetic path is formed only by a metal magnetic thin film, and a joint surface between the magnetic core and the non-magnetic member is directly Cr or
A base film made of Ti and a layer of Ag, Pd or Pt are formed, and A
Each of the joining surfaces is joined by interdiffusion of g, Pd or Pt layers.

[0010] The present invention relates to an A-type magnetic head having a pair of magnetic cores formed on its joint surface
g, Pd or Pt layers are joined by mutual diffusion, and a non-magnetic member and a magnetic core, which are arranged in contact with the magnetic core and have a surface facing the sliding surface of the recording medium, are attached to the respective joining surfaces. Since the bonding is performed by the interdiffusion of the formed Ag, Pt or Pt layer, the magnetic gap and other bonding portions can be bonded firmly by a low-temperature treatment. Therefore, the influence of distortion due to the coefficient of thermal expansion is suppressed, and crystallization does not occur even when an amorphous alloy film is used as the metal magnetic thin film, and good head characteristics can be obtained. Also, since it is joined with a noble metal of Ag, Pd or Pt, it has excellent weather resistance. The underlayer consisting of Cr or Ti under the Ag, Pd or Pt layer improves the adhesion strength of the Ag, Pd or Pt layer to the magnetic core, metal magnetic thin film and non-magnetic substrate, resulting in higher reliability. , A magnetic head having a high density is obtained.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION

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

The magnetic head according to the present invention basically has a bonding surface (magnetic gap portion and other portions) required by the magnetic head.
Are formed by depositing layers of Ag, Pd or Pt, respectively, performing low-temperature heat treatment thereon, and joining and integrating the layers by mutual diffusion of the layers.

FIG. 3 shows a case in which the basic configuration is applied to a ferrite head, which will be described together with its manufacturing method. In this example, as shown in FIG. 3A, a layer 3 of Ag, Pd or Pt is coated on the bonding surfaces 1a and 2a including the magnetic gap forming surfaces of the pair of ferrite cores 1 and 2 by a vapor deposition method, a sputtering method, or the like. Form.

Next, as shown in FIG. 3B, a pair of ferrite cores 1 and 2 are butted so that the layers 3 are in contact with each other.
Under a pressure of about 100 kgf / cm ² , a vacuum furnace is used to perform heat treatment at, for example, 250 ° C. for one hour in an atmosphere of the order of 10 ⁻⁶ Torr, and the layers 3 are bonded together by mutual diffusion. Become Ag, Pd, or Pt is non-magnetic, and forms a target ferrite head 4 shown in FIG. 3C joined thereto with a magnetic gap g.

Here, as the joining conditions, the joining can be performed at a joining pressure of 10 kgf / cm ² or more and a heat treatment temperature of 400 ° C. or less. According to this method, bonding excellent in bonding strength, weather resistance, and the like can be performed at a low temperature of 400 ° C. or less.

Further, as shown in FIG. 4, a two-layer structure is formed by interposing a nonmagnetic underlayer 5 of, for example, Cr or Ti under the layer 3 of Ag, Pd or Pt, respectively. Lg is the gap length. According to the ferrite head 6 having such a configuration, since the base film 5 has good adhesion to the ferrite cores 1 and 2, the adhesive strength between the ferrite cores 1 and 2 and the Ag, Pd or Pt layer 3 is increased, and the ferrite head 6 is stronger. A bond is obtained.

Next, Table 1 shows the transverse rupture strength (kgf / m) when the ferrite cores 1 and 2 were joined using Ag and Pd as the joining layer 3 respectively.
m ² ). However, Cr was used as the base film 5.

[0018]

[Table 1]

The high-melting-point glass used for ordinary head gap bonding has a transverse rupture strength of about 4.3 kgf / mm ² . According to Table 1, it is recognized that the bending strength by Pd and Ag is equal to or higher than the bending strength of the conventional high melting point glass, and that the glass is firmly joined. Note that a sufficient transverse rupture force can be obtained also for Pt.

FIG. 1 shows a case where the present invention is applied to a magnetic head according to an embodiment of the present invention, that is, a laminate head. The laminating head 28 includes a pair of laminating cores 22 in which a plurality of metal magnetic films 21 and a non-magnetic film (not shown) are laminated.
And 23 are joined to form a magnetic gap g, a non-magnetic substrate 24 made of, for example, Mn-Zn ferrite is disposed on both surfaces of the laminated cores 22 and 23 in the track width direction, and both ends in the recording medium sliding direction. And a reinforcing member 25 of the same material. 27 is a glass material.

In the laminating head 28 of the present embodiment, the non-magnetic underlayer 5 made of Cr or Ti described above and the layer 3 of Ag, Pd, or Pt are used particularly for the joints 26 indicated by oblique lines. To join. That is, the bonding portion forming the magnetic gap, the metal magnetic film 21
The joint between the non-magnetic substrate 24 and the auxiliary member 25 is joined with the base film 5 and the layer 3.

FIG. 2 shows a magnetic head according to another embodiment of the present invention,
That is, a case where the present invention is applied to a laminating head of another shape is shown.

The laminating head 29 similarly has a plurality of metal magnetic films
A magnetic gap g is formed by joining a pair of laminated cores 22 and 23 in which a non-magnetic film (not shown) 21 and 21 are laminated, and Mn-Zn ferrite or the like is formed on both sides of the laminated cores 22 and 23 in the track width direction. A non-magnetic substrate 24 is arranged.

Here, the laminated core 22 or 23 and the non-magnetic substrate 24 are used as the magnetic core before the formation of the magnetic gap.

In the laminating head 29 of the present embodiment, in particular, the joining portion 26 indicated by oblique lines is formed by using the above-described nonmagnetic underlayer 5 made of Cr or Ti and the layer 3 of Ag, Pd or Pt. Join. That is, the bonding portion forming the magnetic gap, the metal magnetic film 21
And the non-magnetic substrate 24 are joined by using the base film 5 and the layer 3.

According to the laminating heads 28 and 29 described above, Ag, Pd
Alternatively, the magnetic gap and other necessary bonding portions 26 are bonded by the interdiffusion of the Pt layer 3, so that the bonding can be performed firmly at a low temperature, thereby reducing distortion due to the coefficient of thermal expansion. can do.

For example, laminated cores 22 and 2 made of an amorphous alloy film
Even with the use of 3, the laminated cores 22 and 23 are joined without being crystallized, and a head having good head characteristics can be obtained.

Further, since the underlayer 5 made of Cr or Ti is provided under the layer 3 of Ag, Pd or Pt, the metal magnetic film 21 of the laminate core can be formed.
The adhesive strength between the non-magnetic substrate 24 and the Ag, Pd or Pt layer 3 is increased, and stronger bonding is obtained.

Further, since a noble metal of Ag, Pd, or Pt is used as a bonding material, a head having high weather resistance and high reliability can be obtained.

[0030]

【The invention's effect】

According to the magnetic head of the present invention, in a so-called laminate head, a non-magnetic member and a magnetic core disposed between a pair of magnetic cores forming a magnetic gap and having a surface facing a sliding surface of a recording medium are Ag. By using a Pd or Pt layer and joining by low-temperature treatment, the influence of distortion due to the coefficient of thermal expansion is reduced, and deterioration of magnetic properties, cracks and the like are not induced.

Even when an amorphous alloy is used as the metal magnetic thin film, the head characteristics are not deteriorated by joining at a low temperature equal to or lower than the crystallization temperature of the amorphous.

Since the layers are bonded by interdiffusion of Ag, Pd or Pt layers, the bonding strength is high, and since the layers are so-called noble metals, they have excellent weather resistance.

In addition, since the Cr or Ti underlayer is formed under the Ag, Pd or Pt layer, the magnetic core, the metal magnetic thin film, and the non-magnetic substrate are further bonded to the Ag, Pd or Pt layer. Strength increases,
The joining strength is further improved. Therefore, a highly reliable magnetic head can be provided.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a magnetic head according to an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a magnetic head according to another embodiment of the present invention.

3A to 3C are manufacturing process diagrams of a magnetic head for explaining a basic configuration of the present invention.

FIG. 4 is a configuration diagram of a magnetic head for explaining the configuration of the present invention.

[Explanation of symbols]

21 ... Metal magnetic film, 22,23 ... Laminated core, 24 ...
・ Non-magnetic substrate, 25 ・ ・ ・ ・ Reinforcing member, 26 ・ ・ ・ ・ Joint, 27 ・ ・ ・ ・
Glass material, 28,29 ・ ・ ・ Lamination head

 ──────────────────────────────────────────────────続 き Continuing on the front page Referee Judge Koichi Asano Judge Hiroaki Takase Judge Jiro Naito (56) References JP-A-63-142508 (JP, A) JP-A-3-97109 (JP, A) Hei 1-109806 (JP, U) JP-B-39-18648 (JP, B1) US Patent 3672045 (US, A)

Claims (1)

(57) [Claims] 1. A magnetic head in which a pair of magnetic cores are joined via a gap material, wherein the magnetic core comprises a laminated film of a non-magnetic film and a metal magnetic film, and the recording medium slides in contact with the magnetic core. A non-magnetic member having a surface facing the surface is arranged, and a magnetic path is formed only by the metal magnetic thin film, and a joining surface between the magnetic core and the non-magnetic member is directly made of Cr or Ti. A base film, and A on the base film
A magnetic head in which a layer of g, Pd or Pt is formed, and the respective bonding surfaces are joined by mutual diffusion of the Ag, Pd or Pt layer.