JPH04289507A - Magnetic head - Google Patents

Abstract

PURPOSE:To allow the generation of strong magnetic fields at the front ends of magnetic poles and to execute ultra-high density magnetic recording by using a Cr oxide for forming a magnetic gap. CONSTITUTION:A magnetic film 15 expressed by the compsn. formula of general formula TxMyCz is stuck to one magnetic gap forming surface side of a pair of magnetic core half bodies 13, 14 consisting of ferrite and this magnetic head has the magnetic core constituted by butting such core half bodies against each other via the magnetic gap. The oxide 16 of Cr is used as the film for forming such magnetic gap. In this general formula, x, y, z denote respective compsn. ratios as atomic %; T is at least one kind of the elements selected from a group consisting of Fe, Co, Ni; M is at least one kind of the elements selected from a group consisting of Hf, Zr, Ta, Nb, Ti; C denotes carbon; the compsn. range satisfies 5<=y<=25, 3<=z<=25, x+y+z=100.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to magnetic disk devices, VT
The present invention relates to a magnetic head used for R, etc., and particularly relates to a magnetic head using a magnetic film having high saturation magnetic flux density, high magnetic permeability, low magnetostriction constant, high heat resistance, and corrosion resistance.

0002

[Background Art] In recent years, magnetic recording technology has made remarkable progress. In the field of home VTRs, recording densities have been increased in order to make them smaller and lighter, and in the field of magnetic disk drives to increase their capacity. It is progressing.

In particular, when considering magnetic disk devices, in order to achieve higher recording density, it is necessary to reduce the inductance of the core because the magnetic head is used in a high frequency region, and it is necessary to reduce the inductance of the core. is necessary. However, in a monolithic magnetic head in which the magnetic core 1 shown in FIG. 6 is joined to the slider 3 with a magnetic gap 2 and a winding 4 is applied, it is difficult to reduce the inductance, and the inductance is around 10 μm. It is also very difficult to make the track narrower when considering machinability.

[0004] In order to compensate for this drawback, a composite type magnetic head has been developed which is constructed by combining a magnetic core and a ceramic slider. Furthermore, in order to generate a strong recording magnetic field capable of recording on high coercivity media, metal-in-gap composite heads are also available, in which a magnetic film with a high saturation magnetic flux density is attached near the magnetic gap of the core. It has been put into practical use. FIG. 7 is an external perspective view showing an example of a magnetic core of a metal-in-gap composite head, and FIG. 8 is an enlarged plan view showing a part of the surface facing the recording medium. By bonding the I-type magnetic core half 5 with the metal magnetic film 7 attached to the magnetic gap forming surface side and the C-type magnetic core half 6 with glass (A) 9 through the magnetic gap 8, magnetic Configure the circuit. At this time, a SiO2 film is usually used as the film that forms the magnetic gap. This magnetic core 10 is connected to a CaTiO3 slider 1 as shown in FIG.
Installed in the cutout part provided in a part of the rail part of 1,
A composite magnetic head is constructed by bonding and fixing with glass (B) 12.

In the magnetic head having the above structure, the corrosion resistance and water resistance of the glass are extremely important characteristics from the viewpoint of reliability of the magnetic head, and in order to maintain high reliability, it is necessary to use glass with a high melting point as much as possible. There is a need. For this reason, it is said that a bonding temperature of at least about 550° C. is required.

[0006] When manufacturing a composite head,
As mentioned above, two glass bonding steps are required: glass bonding (I) for forming the magnetic core and glass bonding (II) for fixing the core to the slider. In the process of bonding (II), in order to prevent the glass (A) of the magnetic core from softening and the resulting loosening, the temperature difference between bonding (I) and bonding (II) must be A temperature of at least 150°C is required (for example, JP-A-63
(Refer to Publication No.-12343). Therefore, the glass bonding step (I) needs to be performed at about 700° C. in order to ensure the reliability of the glass (B).

From this point of view, magnetic films are required to have high heat resistance. Conventionally, Fe-Al-Si alloy thin films have been applied to magnetic heads as materials with such heat resistance (see Japanese Patent Laid-Open No. 74110/1983).
. However, as the coercive force of recording media increases, a magnetic film for magnetic heads having a higher saturation magnetic flux density has become necessary.

[0008] In recent years, Fe-Ga-Si film
234509; JP 62-104108, etc.), Fe-C multilayer films (JP 63-65604; JP 63-80509, etc.), Co-based and Fe-based compositionally modulated nitride films. (JP-A-62-210607, JP-A-63-57758, JP-A-63-25)
4708), Co-(Ta, Ti, Zr, Hf,
Nb, Mo)-C film ("Japan Institute of Metals Spring Conference 1989
2019 General Lecture Summary” Lecture No. 128; “Japan Institute of Metals Autumn Conference 1989 General Lecture Outline” Lecture No. 252 and 2
53), Fe-(Ti, Zr, Hf, V, Nb, Ta)
-C membrane (“IEICE Technical Report” MR-89-12, P9 (198
9); Summary of the 13th Japanese Society of Applied Magnetics Academic Lectures (19
89), P484-485), and other magnetic films having high saturation magnetic flux density and excellent heat resistance are being searched for.

In particular, Fe-M-C film, Co-M-C (M
=Ta, Zr, Hf, Nb, Ti) film also has a heat resistance of 70
It is considered promising because it is high at around 0°C and the saturation magnetic flux density is high at around 1.5 to 1.7 T. In addition, these films are
The M carbide produced by heat treatment is Fe or Co
It is known that by suppressing the growth of crystal grains and forming a fine structure with a crystal grain size of about 100 Å, it exhibits high thermal stability and good soft magnetism. Furthermore, it is expected that magnetic heads using these films will be able to realize high-density recording by combining them with high coercive force media, and therefore studies are underway to develop magnetic heads into heads.

0010

[Problems to be Solved by the Invention] However, when the present inventors fabricated a head using Fe-M-C or Co-M-C films, the reaction between the film and the glass used for bonding was significant, and the film I learned that there are problems such as the carbon melting into the glass, or the glass becoming brittle due to being reduced to carbon in the film, making it impossible to obtain sufficient bonding strength. In particular, it has been found that this reaction occurs more easily at higher temperatures and becomes an obstacle in producing a highly reliable composite magnetic head. In addition, S
It was also found that the reaction between the film and the glass could not be prevented because the iO2 film was easily fused with the bonding glass.

The object of the present invention is to prevent the above-described reaction between the magnetic film and glass, and to use a magnetic film that has high saturation magnetic flux density, high magnetic permeability, low magnetostriction constant, and has a heat resistance temperature of 700° C. or more. An object of the present invention is to provide a high-performance magnetic head.

0012

[Means for Solving the Problems] The present invention provides the general formula TXMYCZ (
However, X, Y, and Z each represent the composition ratio as atomic %,
T represents at least one element selected from the group consisting of Fe, Co, and Ni; M represents at least one element selected from the group consisting of Hf, Zr, Ta, Nb, and Ti; C represents carbon; the composition range is However, 5≦Y≦25, 3≦Z≦25, X+
In a magnetic head having a magnetic core formed by attaching a magnetic film represented by the composition formula (Y + Z = 100) and butting these magnetic core halves together via a magnetic gap, the magnetic gap is formed. This magnetic head is characterized in that a Cr oxide is used as a film for this purpose.

[0013]

[Operation] In the present invention, by using a Cr oxide film instead of the SiO2 film for the film forming the magnetic gap, the reaction between the Fe-MC, Co-MC film and glass is prevented. It is possible. This is due to the very low reactivity between the Cr oxide and the Fe-MC, Co-MC, and glass films. Also,
Since the Cr film also has the effect of preventing the reaction between the Fe-M-C, Co-M-C film and glass, in the present invention, the Cr film
In addition to the r oxide film, a multilayer film including a Cr oxide film and a Cr film may be used. When only a Cr film is used, it is difficult to distinguish it from a magnetic film using an optical microscope, but when a film in which Cr is oxidized as in the present invention is used, it is also possible to distinguish using an optical microscope. No problems will occur. In addition, as the Cr oxide film in the present invention, especially C
An r2O3 film or the like is desirable.

[0014]

EXAMPLES (Example 1) FIG. 1 is an external perspective view of a magnetic head core manufactured by applying the present invention, and FIG. 2 is an enlarged plan view showing a part of its recording medium facing surface. 1 and 2, 13 and 14 are magnetic core halves made of Mn-Zn ferrite, 15 is a magnetic film formed on the magnetic gap forming surface side of the I-type magnetic core half 13, and 16 is a magnetic film 15. This is a Cr oxide film formed on top.

Co80.0H was deposited on a Mn-Zn ferrite substrate using an RF magnetron sputtering device.
A magnetic film with a composition of f8.5C11.5 (at%) is 2μ
After forming the m film, 0.5 μm of various films shown in Table 1 were formed as a film to form a gap thereon, and a further 0.05 μm thick film was formed.
A thick film of glass for welding was formed. Next, PbO, SiO
2. Glass containing B2O3 as a main component was heated to 700°C to bond a bonding block for producing a core. By cutting and processing this bonding block, a magnetic head core as shown in FIG. 1 was manufactured.

Table 1 shows the results of studies regarding the feasibility of determining voids in glass, film erosion due to reactions between the film and glass, film peeling, and gaps.

[0017]

[Table 1] In addition, Figure 4 shows the locations of study items, etc.
The amount of voids 28 generated in the glass 27, the magnetic film 25 existing between the glass 27 and the ferrite core 23, and the Si
Film cracking and film peeling were observed at the portion indicated by 29 of the O2 film.

[0018] From Table 1, when a Cr film or a Cr2O3 film is used, almost no reaction is observed, but when other films are used, glass voids, film cracks, and film peeling occur. It is clear that there is a problem, such as the occurrence of On the other hand, SiO2 is used as the gap-forming film as before.
When glass bonding is performed, as shown in FIG. 3, the reaction between the magnetic film and the glass is significant, the film melts into the glass, and many voids are created in the glass. Furthermore, the glass becomes brittle because it is reduced by C in the film, and the core halves separate from each other during processing, making it impossible to form a magnetic head core. In addition, Figure 3
, 18 and 19 are magnetic cores made of ferrite, 20 is a magnetic film, 21 is a SiO2 film, and 22 is glass.

Further, when a magnetic core using a Cr film or a Cr2O3 film was used to process a magnetic head, the bonding strength of the glass was sufficient, and the magnetic head could be easily manufactured. However, since the Cr film has a metallic luster, it is difficult to distinguish the boundary with the Co-Hf-C film using an optical microscope, making it difficult to accurately read the gap length. On the other hand, it has been found that when a Cr2O3 film is used, the gap can be easily determined using an optical microscope, and the dimensions of the head can be measured accurately.

(Example 2) Fe81.5Ta7 for magnetic film
．． A method of using a 9C10.6 (at%) film (film thickness: 2 μm) and forming a Cr oxide film thereon as a film for forming a gap was studied in more detail. In this example, when forming a Cr oxide film by sputtering, an oxide target such as Cr2O3 is used. However, other methods, such as using a Cr target in a mixture of Ar and O2 gas, A Cr oxide film can also be formed by sputtering.

The sputtering conditions were as follows. Exhaust ultimate vacuum: 1 x 10-6 Torr or less input
Electron: 2.0W/cm2 Gas pressure (total pressure): 4×1
0-3 Torr board Temperature: Water Cold film thickness: 0.5 μm Gas pressure is total pressure 4
×10-3 Torr, O2 gas partial pressure 0-30%
It was varied within the range of.

Table 2 shows whether the bonding block gap can be determined, the bonding strength, and the reaction between the film and the glass when glass bonding is performed using Cr oxide films formed at different O2 partial pressures. Bond strength was good in all cases studied. However, the gap could be easily determined using an optical microscope when the O2 partial pressure was 20% or more.

[0023]

[Table 2]

(Embodiment 3) Next, the characteristics of the magnetic head obtained by the present invention will be described. As mentioned above, FIG. 1 is an external perspective view showing an example of a magnetic head core to which the present invention is applied, and FIG. 2 is an enlarged plan view showing the surface facing the recording medium. A magnetic head core with such a configuration is shown in FIG.
As shown in Figure 2, it was fixed to a CaTiO3 slider with glass, then attached to a gimbal and evaluated as a magnetic head for a hard disk drive.

Saturation magnetic flux density Bs=1.7T as a magnetic film
Fe82.0Hf7.5Zr8.0C11.5 (at
%) film, etc., and Cr as the film forming the magnetic gap.
A magnetic head according to the present invention manufactured using a 2O3 film,
FIG. 5 shows the relationship between the measured medium coercive force and critical recording density D50 (KFCI) for a magnetic head fabricated using a conventional Fe-Al-Si film with Bs=1.7T. In the case of the magnetic head of the present invention using Fe-Hf-C film and Co-Zr-C film, even if the medium coercive force increases to 1500 Oe or more, the magnetic core tip does not saturate and a strong recording magnetic field is generated. Therefore, sufficient recording is possible, and D50 also increases as the medium coercive force increases. On the other hand, Fe
In the case of a conventional magnetic head using an -Al-Si film, D50 becomes almost constant when the medium coercive force becomes 1500 Oe or more.

Therefore, by using a magnetic head using a magnetic film having a high Bs to which the present invention is applied, it is possible to
It was confirmed that writing was possible even on a medium with a coercive force of 0 Oe. In addition, when we compared the reproduction output using a medium with a coercive force of 1000 Oe, we found that Fe-Al-
It was confirmed that the performance was equal to or better than that of a conventional magnetic head using a Si film, and the reproduction characteristics were also good.

[0027]

Effects of the Invention The magnetic head according to the present invention has Fe-M-
C, Co-M-C (M=Hf, Zr, Ta, Nb, Ti
), the film thickness is 1 μm.
Even if the Tw width is as small as 5 μm or less, a strong magnetic field can be generated at the tip of the magnetic pole without causing magnetic saturation, and ultra-high density magnetic recording can be achieved.

Furthermore, the Cr oxide film that forms the magnetic film and the gap in the present invention can be formed using a normal RF magnetron sputtering device, so the manufacturing method is simple and the manufacturing cost is low and high. It also has the advantage of ensuring trust.

[Brief explanation of the drawing]

FIG. 1 is an external perspective view of a magnetic head core to which the present invention is applied.

FIG. 2 is an enlarged plan view of the surface facing the magnetic recording medium.

FIG. 3 is a sketch diagram created based on an observation photograph of a magnetic head core when SiO2 is used for the gap film.

FIG. 4 is a schematic diagram showing the positions in the magnetic head core investigated in cases where various reaction prevention films were used.

FIG. 5 is a characteristic diagram showing the relationship between medium coercive force and critical recording density measured using a magnetic head to which the present invention is applied.

FIG. 6 is an external perspective view of a conventional monolithic magnetic head.

FIG. 7 is an external perspective view of a conventional metal-in-gap type composite head core.

FIG. 8 is an enlarged plan view of the surface facing the magnetic recording medium.

FIG. 9 is an external perspective view of a magnetic head in which a magnetic core is embedded.

[Explanation of symbols]

1 Magnetic core 2 Magnetic gap 3 Slider 4 Coil 5 Magnetic core half 6 Magnetic core half 7 Magnetic film 8 Magnetic gap 9 Glass (A) 10 Magnetic core 11 Magnetic gap 12 Glass (B) 13 Magnetic core half 14 Magnetic core half 15 Magnetic film 16　Cr oxide film 17 Glass 18 Ferrite 19 Ferrite 20 Magnetic film 21 Magnetic gap (SiO2 film) 22 Glass 23 Ferrite 24 Ferrite 25 Magnetic film 26 Reaction prevention film 27 Glass 28 Glass void 29 Membrane peeling part

Claims (2)

[Claims] Claim 1: A magnetic material having the general formula TXMYCZ (where X, Y, and Z each represent a composition ratio in atomic %) on the magnetic gap forming surface side of at least one of a pair of magnetic core halves made of ferrite. , T is at least one element selected from the group consisting of Fe, Co, and Ni, M is Hf,
At least one element selected from the group consisting of Zr, Ta, Nb, and Ti, C represents carbon, and the composition range is 5≦Y
≦25, 3≦Z≦25, X+Y+Z=100)
In a magnetic head having a magnetic core configured by adhering a magnetic film represented by the composition formula and abutting the magnetic core halves together via a magnetic gap, the film forming the magnetic gap is made of Cr oxide. A magnetic head characterized by using. 2. The magnetic head according to claim 1, wherein the Cr oxide film forming the magnetic gap is a Cr2O3 film.