JP2762885B2 - Magnetic head - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head for magnetic recording / reproducing and erasing, and more particularly to a magnetic head in which a metal magnetic material is used as a core material and a track of the magnetic head is used. The present invention relates to a magnetic head suitable for high-density recording / reproducing and erasing, in which a width-regulating groove is filled with glass. Conventionally, a magnetic head for high-density recording uses a metal magnetic material having a high saturation magnetic flux density as a magnetic core material, narrows a magnetic gap to increase linear recording density, and The structure is such that the core width is reduced to increase the track density. Focusing on this track width, an ordinary narrow track magnetic head has a core magnetic resistance,
From the viewpoints of sliding resistance, mechanical strength, and the like, a method has been adopted in which the width of the magnetic core is widened and a throttle groove is provided only in a necessary portion near the magnetic gap to obtain a required track width. Then, the aperture groove is filled with highly reliable glass as a nonmagnetic material. In such a magnetic head, when glass is directly filled in the narrow track aperture groove, the characteristic of the magnetic material deteriorates due to the reaction between the metallic magnetic material and the glass. In particular, in a film in which a magnetic material is formed by a thin film forming technique, the reaction with glass becomes more severe than in a bulk material. Therefore, for example, Japanese Patent Application Laid-Open No.
As described in JP-A-11, a method in which a film of a high melting point material such as SiO, SiO ₂ or high melting point glass having a thickness of several thousand to several μm is applied as a protective film between a metal magnetic material and a filled glass. Has been proposed. In Japanese Patent Application Laid-Open No. 60-125909, since the wettability between a metal magnetic material and glass cannot be sufficiently obtained, a metal film and an oxidized film are formed in a track width regulating groove of a magnetic head using a metal magnetic material. There has been proposed a method of providing an object film and filling the oxide film with glass. other,
Japanese Patent Application Laid-Open No. Sho 59-142716 discloses a similar component. FIG. 5 is a plan view of a magnetic head using a conventional metal magnetic film, facing a recording medium. The magnetic head comprises two magnetic core halves 15, 15 '. Each core half is made of a composite material of a ferrite 10 and a metal magnetic film 11, and has a structure in which glass 12 is filled in a track width narrowing groove portion and reinforced. The core halves 15, 15 'are joined via a non-magnetic gap film 14. In the manufacturing process, a glass 12 is melted and filled after a metal magnetic film 11 is formed on an inclined surface of a ferrite substrate 10 in a manufacturing process. At this time, the glass 12 and a part of the metal magnetic film 11 react with each other, and the magnetic characteristics of the metal magnetic film deteriorate. For this reason, after the metal magnetic film is deposited, a film 13 of a high melting point material such as SiO, SiO ₂ or high melting point glass having a thickness of several thousand to several μm is deposited as a protective film, and this is then applied to the metal magnetic film and the glass. It is a reaction prevention film. However, this method has the following disadvantages. (1) Bubbles are generated by the reaction between the glass and the protective film. The air bubbles are trapped in the glass and form holes on the surface facing the recording medium, causing damage to the medium. (2) When the thickness of the oxide protective film is set to several μm or less, the difference in thermal expansion coefficient between the metal magnetic film and the core material does not cause much problem. Not enough film thickness. Therefore, the reaction layer with glass reaches the metal magnetic film, and the characteristics of the metal magnetic film deteriorate. (3) Further, if the oxide protective film is formed to have a thickness of several μm or more so that the reaction layer does not reach the metal magnetic film, the difference in the thermal expansion coefficient of the protective film cannot be ignored and the glass has slack. Would. Also, the amount of bubbles increases. FIG. 6 is a plan view of a magnetic head facing a recording medium to show another conventional example. This magnetic head comprises two core halves 15, 15 'made of a metallic magnetic material (for example, Sendust) 11. The core half is provided with a notch groove for a narrow track near the magnetic gap, and is joined and integrated via the magnetic gap 14. In this embodiment, in which the bonding is performed by filling the glass 12, the nonmagnetic metal film 16 is applied to the glass filling groove for the purpose of improving the adhesion between the metal magnetic material 11 and the glass and the bonding strength. It has a structure in which an oxide film is deposited thereon and then filled with glass. As a result, the adhesive force between the metal magnetic material 11 such as sendust alloy and the non-magnetic metal film 16 and the non-magnetic metal film 1
As a result, a chain of adhesion between objects having high affinity, such as an adhesion between the metal oxide film 13 and the metal oxide film 13 and an adhesion between the metal oxide film 13 and the glass 12, is obtained. Has been proposed to be very robust. However, it has been found that the above-described structure has the following disadvantages. (1) Since the metal oxide film 13 is present on the surface to be filled with the glass 12 as in the conventional example, bubbles are generated by the reaction. Conversely, when a metal oxide film that does not react with glass is used, the adhesive strength is poor and the glass is lost. An object of the present invention is to eliminate the above-mentioned conventional disadvantages,
It is an object of the present invention to improve the characteristic deterioration of a magnetic head composed of a combination of a metal acid film and glass, and to greatly improve the production yield. The above object is achieved by providing a protective film in the order of a non-magnetic oxide or carbide and a non-magnetic metal film in a groove width of a track width of a magnetic head using a metal magnetic material. This is achieved by filling the nonmagnetic metal film with glass. As the metallic magnetic material, an amorphous magnetic alloy, an Fe-Al-Si alloy, a Fi-Fe alloy, an iron nitride or the like having a high saturation magnetic flux density formed by a thin film forming technique such as evaporation or sputtering. Consists of The protective film is made of a group of SiO ₂ , Al ₂ O ₃ and ZrO ₂ as a non-magnetic oxide or carbide;
A material selected from the group consisting of TiC, SiC, and B ₄ C is selected. As the non-magnetic metal film, Cr, Ti, Mo,
It consists of one or more of the group of Al, Cu, Si, Ge. According to the present invention, a non-magnetic oxide film or a carbide film is formed on a metal magnetic film, and a non-magnetic metal film is further formed thereon.
And it consists of filling glass. By forming a high-hardness non-magnetic oxide film or carbide film on the metal magnetic film, the end of the track width formed by the metal magnetic film becomes clear and a track width with high dimensional accuracy can be obtained. Can be In addition, there is no droop at the end of the magnetic gap. By further forming a non-magnetic metal film on the non-magnetic oxide film or the carbide film, the filled glass does not directly contact the non-magnetic oxide film or the carbide film, so that almost no bubbles are generated in the filled glass. Further, the nonmagnetic metal film of the present invention is easily wettable with glass containing PbO as a main component, and has a strong adhesive force. Further, since the depth is smaller than the reaction depth between the nonmagnetic oxide film or the carbide film and the glass, the film thickness can be reduced. Being thin makes the difference in thermal expansion coefficient between each constituent material almost irrelevant. An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a plan view of a magnetic head according to the present invention facing a recording medium. FIG. 2 is a perspective view thereof. FIG. 3 is a side view of a partial piece for explaining an example of the manufacturing method. FIG. 4 is a diagram showing an embodiment. In FIGS. 1 and 2, reference numerals 30 and 30 'denote core halves constituting a magnetic head core. A groove 37 for coil winding is formed in one core half 30. Each of the core halves 30, 30 'is composed of a protective core material 31 and a metal magnetic film 32, and protective films 33 and 34 are formed between the glass 35 and the metal magnetic film 32. The protective film is formed in the order of nonmagnetic oxide or carbide 33 and nonmagnetic metal film 34. Then, the two core halves 30, 30 'are joined and integrated by the glass 35 via the non-magnetic magnetic gap film. The metal magnetic film 32 has a structure formed on an inclined surface which is processed into a mountain shape in order to obtain a track width tw smaller than the core width T. Also, the metal magnetic film 32,
The protective films 33 and 34 are formed not only on the surface facing the recording medium but also around the coil winding window. A specific embodiment will be described below in comparison with a conventional example. FIG. 3 is a side view of the core piece. Mn-Z
A number of V-shaped grooves were formed on the upper surface of the n-ferrite substrate 30 so as to leave a mountain-shaped protrusion. The angle θ of the chevron was 60 °. Next, Co-Nb-Z
An amorphous alloy film 32 of r was formed into a four-layer film having a thickness of 6 μm by a sputtering method (not shown). At this time, a SiO ₂ film having a thickness of about 0.05 μm was also formed between the amorphous alloy film layers by a sputtering method to form a multilayer film in order to improve high frequency characteristics. Next, on the metal magnetic film 32, as a protective film, a non-magnetic magnetized material or carbide 33, a non-magnetic metal film 3
The layers were formed in the order of No. 4 by a sputtering method. Then, PbO
Was heated to 460 ° C. and filled with lead glass 35 containing B ₂ O ₃ , SiO ₂ and Al ₂ O ₃ . The magnetic core piece thus configured is ground and polished to the AA plane to expose the metal magnetic film 32 by the track width, and the two core pieces are symmetrically overlapped and heated again at 460 °. Glass 35
Were joined by softening and melting. This was cut into a core to obtain a magnetic head core as shown in FIG. Tables 1 and 2 show the results of various studies on the material and configuration of the protective film for the magnetic head manufactured by such a process. [Table 1] [Table 2] Table 1 shows the bubble yield in the glass, the reaction between the metal magnetic film and the protective film, the reaction between the metal magnetic film and the glass, and the crack state of the glass, which were examined for the magnetic head manufactured by the conventional method. . Table 2 shows the results of investigation on the material and constitution of the protective film according to the present invention. FIGS. 4 (a) to 4 (e) are schematic views showing the results of Tables 1 and 2 and are the main parts of the plane facing the recording medium of the magnetic head core. No. 1 in Conventional Example Table 1 corresponds to FIG. It was found that the metal magnetic film 32 was directly filled with the glass 35, and the metal magnetic film 32 and the glass 35 reacted with each other to form a permanent magnet film 41 having a coercive force of 100 Oe or more. This permanent magnet film 41 is an important problem because it erases recorded signals. In addition, the magnetic gap end portion 44 also reacted, and it was found that the gap was widened. Further, many bubbles 38 were found in the glass. No. 2 corresponds to FIG. The SiO ₂ film was formed as a protective film to a thickness of 2 μm.
The SiO ₂ film 40 completely disappears due to the reaction with the glass 35, the reaction also occurs with the metal magnetic film 32, and the permanent magnet film 4
It was found that 1 was formed. No. 3 is the result of preventing the reaction by increasing the thickness of the SiO ₂ film to 5 μm. As shown in FIG.
Forty portions of the _two films react, but remain as the SiO ₂ film 39 and do not reach the metal magnetic film 32. However, cracks 42 occurred in the glass 35. In addition, many bubbles 38 were generated, and a favorable result was not obtained. No. 4 and No. 5 show that Cr was deposited on the metal magnetic film 32.
This is a result of forming a film or a Ti film 34 and filling the glass 35. In this configuration, generation of air bubbles was not recognized, but a thin reaction layer was recognized at the boundary between the metal magnetic film 32 and the Cr film 43, and a magnetic layer of about 10 Oe was formed. The reaction layer causes a signal to be degraded during recording and reproduction. Nos. 6 and 7 are examples in which a Cr film and a SiO ₂ film were formed in this order as a protective film on the metal magnetic film 32.
This is an example in which a film and an Al ₂ O ₃ film are formed in this order. In this case as well, the portion in contact with the glass is the oxide film, and many bubbles were generated due to the reaction between the glass 35 and the oxide film 40 as in FIG. No cracks occurred because the thickness of the oxide film was as thin as 1 μm. On the other hand, Table 2 shows the experimental results according to the present invention. This result is obtained by forming a non-magnetic oxide film or carbide film 33 and a non-magnetic metal film 34 in this order on the metal magnetic film 32 and then filling the glass 35 with the structure shown in FIG. Table 2 shows the non-magnetic oxide film or carbide film 3
3 is SiO ₂ , Al ₂ O ₃ , ZrO ₂ , TiC, Si
C, B ₄ C, and the nonmagnetic metal film is Cr, Ti, Mo, A
Similarly, it was formed of 1, Ge, and Si by a sputtering method. As a result, as shown in Nos. 8 to 20, it was found that bubbles were less generated in the glass and a higher yield was obtained as compared with the conventional method. It was also found that even a thin film having a thickness of 0.1 to 1 μm was excellent in the reaction preventing effect. The protective film of the present invention is preferably provided not only on the surface facing the recording medium, but also on all portions where the metal magnetic film and the glass come into contact. For example, it is effective to accurately define the gap depth inside the coil winding groove near the magnetic gap. The protective sputtering conditions of the present invention are Ar gas 5
The operation was performed at × 10 ⁻³ Torr, and after sufficient washing, lead glass was melt-filled. Since the crystallization temperature of an amorphous magnetic alloy is 500 ° C. to 560 ° C. as the filling glass, 450 ° C. to 530 ° C. is suitable as a condition that does not cause crystallization. Therefore, PbO is 75% by weight as a low melting glass.
The one disclosed in Japanese Utility Model Laid-Open No. 57-195621 containing 〜85% was used. Glass filling was performed in an Ar or N ₂ atmosphere. However, lead may be metallized in a glass having a high PbO content, and when filled in an atmosphere containing a small amount of oxygen, lead is not released without bonding. It was found to increase the strength. The amorphous magnetic alloy film used in the present invention is C
An o-based metal-metal system or a metal-metalloid system is used, but a metal-metal system is suitable in consideration of corrosion resistance, abrasion resistance, composition deviation due to sputtering, and the like. On the other hand, Fe—Al—Si (Sendust)
It was confirmed that similar results were obtained for the alloy.
In the case of Sendust, the sputtered film is a film having a large coercive force.
Need to be annealed. Therefore, since it has excellent heat resistance, it can be filled with glass at a higher temperature than an amorphous alloy. However, when the temperature is increased, the reaction with the protective film becomes difficult, and the temperature is preferably 500 ° C. to 600 ° C. Next, a second embodiment will be described below. In this embodiment, a glass film is further formed on the constituent protective film of the above embodiment by a sputtering method.
By performing glass filling, the bubble generation yield was improved. [Table 3] Table 3 shows the results of the experiment. From the above experimental results, a nonmagnetic oxide film or a carbide film as a protective film,
Next, after forming a non-magnetic metal film and further a lead glass film, by filling the glass, the bubble yield in the glass was improved to 90% or more. This also improved the adhesion. Glass film A is PbO85% for sputter target,
B ₂ O ₃ 13%, SiO ₂ 1%, Al ₂ O ₃ 1% (% by weight)
Was used. Glass film B is made of 68% SiO ₂ and PbO
15%, NaO 10%, K ₂ O 6%, CaO 1% (% by weight). As the sputtering conditions for the glass film, 5
By performing the treatment in an atmosphere containing O ₂ %, there is an advantage that an oxygen-deficient state can be compensated. Further, in order to release the gas trapped in the film during sputtering, 300 ° C. to 40 ° C. before filling the glass.
A method of degassing by heating at 0 ° C. is also suitable. In the present invention described above, the protective core is Mn.
In addition to -Zn ferrite, Ni-Zn ferrite can be used. Further, nonmagnetic materials such as crystallized glass and ceramics may be used. When the protective core is made of a magnetic material having a high magnetic permeability, a magnetic path is formed together with the metal magnetic film, so that the magnetic characteristics required for the metal magnetic film at the rear of the magnetic path are reduced. The manufacture of the magnetic head is easy. On the other hand, when a non-magnetic protective core is used, a magnetic path is constituted only by the metal magnetic film. Therefore, the sliding noise is smaller and the S
/ N is improved. Since the inductance is small, the number of coil turns can be increased, and there are advantages such as an improvement in reproduction output. According to the present invention, (1) the problem of the glass reaction with the metal magnetic film is eliminated, and the recording / reproducing characteristics are improved. In other words, the problem that the recording signal is degraded by the reaction layer of the metal magnetic film and the glass is solved. (2) Since the number of bubbles generated in the glass is greatly reduced, the bubble portion does not damage the recording medium surface, and the life of the magnetic head is prolonged. Also, the head manufacturing yield is greatly improved. There are the following effects.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a magnetic head facing a recording medium according to an embodiment of the present invention. FIG. 2 is a perspective view of the magnetic head of FIG. 1; FIG. 3 is a cross-sectional view showing a core piece for explaining a method of manufacturing a magnetic head according to the present invention. 4 (a) to 4 (e) are main part views of a recording medium facing plane in a magnetic head core for comparing and explaining experimental results of the present invention with a conventional example. FIG. 5 is a diagram showing a plane facing a recording medium in a conventional example. FIG. 6 is a diagram showing a plane facing a recording medium according to a conventional example. [Description of References] 30, 30 ': Core half constituting magnetic head, 31 ...
Protective core, 32: metal magnetic film, 33: non-magnetic oxide film or carbide film, 34: non-magnetic metal film, 35: glass,
36: magnetic gap; 37: coil winding groove.

──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Hideo Zama 1410 Inada, Kataida, Ibaraki Pref.In the Tokai Plant of Hitachi, Ltd. Inside the Tokai Plant (56) References JP 7-58527 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) G11B 5/127 G11B 5/23

Claims (1)

(57) [Claims] A pair of magnetic cores facing each other via a magnetic gap,
A throttle groove provided in the vicinity of the magnetic gap of the magnetic core to regulate a track width; and glass filled in the throttle groove, and a metal magnetic material is used for at least a part of the magnetic core in the vicinity of the magnetic gap. In the magnetic head, as an intermediate film provided between the metal magnetic material and the glass, at least two layers of a carbide film disposed on the metal magnetic material side and a non-magnetic metal film disposed on the glass side. A magnetic head characterized by using an intermediate film. 2. 2. The magnetic head according to claim 1, wherein a glass film is further provided on the non-magnetic metal film, and then the glass is filled. 3. 3. The magnetic head according to claim 1, wherein the magnetic core is made of a composite material of the metal magnetic material and ferrite. 4. The magnetic head according to claim 1, wherein the glass is a lead glass. 5. The metal magnetic material is an amorphous magnetic alloy, Fe-Al-
The magnetic head according to any one of claims 1 to 4, wherein the magnetic head is at least one selected from a Si-based alloy, a Ni-Fe alloy, and iron nitride. 6. The carbide film, TiC, SiC, and the magnetic head according to any one of the B ₄ paragraph 1 claims, characterized in that at least one selected from C through fifth term. 7. The non-magnetic metal film is made of Cr, Ti, Mo, Al, C
The magnetic head according to any one of claims 1 to 6, wherein the magnetic head includes at least one selected from u, Si, and Ge.