JP2007280497A - Magnetic head and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that the thickness of the magnetic metal film core formed on a non-magnetic base of a stacked magnetic head is almost the same as the track width, and the magnetic metal film core must be made thinner matching the track width when making the track width smaller and the magnetic metal film core thinner, which makes the magnetic reluctance large declining the head efficiency resulting in smaller head output. <P>SOLUTION: When joining core block halves of a magnetic head via a gap, the magnetic metal film cores are butt joined intentionally staggering them to obtain a structure that has a part where the film cores overlap each other and a part where they do not overlap. Since it is not necessary to make the magnetic metal film core thin even when the track width is made small, the head output can be maintained high. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a read-only magnetic head for a VTR and a tape streamer having excellent head output and reliability in high-density recording and reproduction.

  In recent years, magnetic recording apparatuses such as digital VTRs and streamers that record and reproduce a large amount of information at a high transfer rate have been actively developed. In such a magnetic recording apparatus for recording a large amount of information, the magnetic recording medium is changed from a conventional iron oxide-based medium to a medium having a high coercive force, such as an alloy powder medium or a metal vapor deposition film medium. It was. Development of a magnetic head having a high saturation magnetic flux density and excellent characteristics in a high frequency band of 50 MHz or more is desired so as to be compatible with these media having a high coercive force. In order to meet these demands, metallic magnetic film cores are made by alternately laminating metallic magnetic films such as Sendust, amorphous magnetic alloy or FeTaN and insulating films, and both sides of this metallic magnetic film core are made of nonmagnetic substrates. A laminated magnetic head has been developed that has a sandwiching structure and improved high-frequency characteristics.

An example of a conventional laminated magnetic head is shown in the perspective view of FIG. 5A (see, for example, Patent Document 1). The structure of the magnetic head is a nonmagnetic substrate in which a metal magnetic film core 23 formed by alternately laminating metal magnetic films 21 made of, for example, FeTaN and insulating films 22 made of an SiO ₂ film is made of, for example, calcium titanate ceramics. The magnetic core block 25 is sandwiched by 24. The pair of magnetic core blocks 25 (a) and (b) are joined together via a magnetic gap 28 to form a magnetic head. FIG. 5B shows an enlarged view of the vicinity of the gap on the tape running surface of the magnetic head. Here, the portion where the metal magnetic film cores 23 of the two magnetic core block halves 25 protrude from each other becomes the track width 30 of this head, and recording on the magnetic tape and reproduction of signals from the magnetic tape are performed. To work.

As can be seen from FIG. 3, in the case of the laminated magnetic head, the track width is substantially the same as the thickness of the metal magnetic film core. Here, in order to increase the recording density of the recording medium, it is necessary to reduce the track width. In this case, it is necessary to similarly reduce the thickness of the metal magnetic film core.
JP-A-5-282621

  In the case of a laminated magnetic head, the thickness and track width of the metal magnetic film core formed on the nonmagnetic substrate are substantially the same due to its structure. Therefore, when the track width is reduced, it is necessary to reduce the thickness of the metal magnetic film core accordingly. However, if the thickness of the metal magnetic film core is reduced, the magnetic resistance is increased, and the head efficiency is reduced and the head output is reduced. This tendency becomes more conspicuous when the track width becomes very small, such as about 10 μm or less, or when the relative magnetic permeability of the metal magnetic film core decreases.

  On the other hand, in order to prevent such a decrease in head efficiency, efforts are made to reduce the thickness of the metal magnetic film only in the portion forming the track width near the gap. Examples of this include the examples of JP-A-57-55527 and JP-A-5-290327. However, in the case of Japanese Patent Laid-Open No. 57-55527, the manufacturing process is very complicated, and in the case of Japanese Patent Laid-Open No. 5-290327, the processing accuracy is extremely high, such as grinding a metal magnetic film by machining. High processes are required, and due to the difficulty and complexity of these processes, various problems such as inability to obtain the desired performance, a decrease in manufacturing yield, and an increase in manufacturing cost are newly generated.

  When joining the magnetic core block halves of the magnetic head through the gap, the butt of the metal magnetic film core is intentionally shifted from each other to provide a portion where the butt of the metal magnetic film cores overlap and a portion where they do not overlap. Make the structure. Since the track width is composed of the overlapping portions of the metal magnetic film core, even if the thickness of the metal magnetic film core is increased, the track width can be reduced by providing any portion that is not abutted against each other. It is possible to reduce the thickness, and it is possible to increase the thickness of the metal magnetic film core compared to the track width. This makes it possible to increase the head output while keeping the thickness of the metal magnetic film core large and keeping the magnetic resistance small even if the track width becomes as small as about 10 μm or less.

  Further, if the head to be used is a head that performs a recording operation, the adverse effect that the portion where the buttocks of the metal magnetic film core is offset erases the signal already recorded on the magnetic medium becomes a serious problem. However, by specializing this head as a read-only head, even if the butt of the metal magnetic film core is misaligned, the recorded signal recorded on the magnetic media will not be adversely affected, and the track butt misalignment will not occur. Thus, the magnetic head can be configured while leaving no special processing for removing this butt shift.

  According to the present invention, even when the track width of the magnetic head becomes very small, the magnetic characteristics of the metal magnetic film core can be kept high, and a high-performance magnetic head excellent in frequency characteristics can be realized. It becomes. In addition, without the need for complicated processes and without changing the normal head manufacturing process, the gap between the metal magnetic film cores can be easily shifted by a predetermined amount when gaps are formed. Therefore, it is possible to manufacture by utilizing the current process with excellent manufacturing cost and yield.

  The invention according to claim 1 of the present invention has a structure in which a metal magnetic film core is sandwiched between nonmagnetic substrates. In a magnetic head used as a read-only head, a pair of metal magnetic film cores sandwiched between nonmagnetic substrates. When the track core is formed by abutting the magnetic core block halves with a gap, the track width is 10 μm or less, where the track overlap is the portion where the butts of the pair of metal magnetic film cores overlap. The film thickness of the metal magnetic film core is 2 μm or more than the track width and less than twice the track width, and the track is formed in a state where the pair of metal magnetic film cores are shifted from each other. The thickness of the metal magnetic film core can be increased compared to the track width by providing a portion of the core half that is offset from the butt of the metal magnetic film cores. In addition, it is possible to realize a magnetic head with excellent frequency characteristics and high head output, and since a conventional process can be used in the production process, it is possible to realize a magnetic head with excellent productivity and cost. Note that the film thickness is made less than twice the track width. If the film thickness is larger than this, the crosstalk is affected by the adjacent tracks that have azimuth in the same direction when playback is performed on an actual deck. This is because noise increases.

  The invention according to claim 2 of the present invention is such that the track width is 8 μm or less, and the film thickness of the metal magnetic film core is 1.5 μm or more than the track width and not more than twice the track width. 2. The magnetic head according to claim 1, wherein the track is formed in a state where the pair of metal magnetic film cores are displaced from each other. When the track width is 8 [mu] m or less, the track is shifted to move the metal magnetic film. The effect of increasing the head output by increasing the core film thickness is further increased.

  In the invention according to claim 3 of the present invention, the track width is 8 μm or less, and the film thickness of the metal magnetic film core is 2.0 μm or more than the track width and not more than twice the track width. 2. The magnetic head according to claim 1, wherein the track is formed in a state in which the pair of metal magnetic film cores are shifted from each other, and by increasing the film thickness of the metal magnetic film core by 2.0 μm or more, The effect of increasing the head output is further increased.

  In the invention according to claim 4 of the present invention, the track width is 6 μm or less, and the film thickness of the metal magnetic film core is 1.0 μm or more than the track width and not more than twice the track width. 2. The magnetic head according to claim 1, wherein the track is formed in a state where the pair of metal magnetic film cores are shifted from each other. When the track width is 6 [mu] m or less, the track is shifted to move the metal magnetic film. The effect of increasing the head output by increasing the core film thickness is further increased.

  In the invention according to claim 5 of the present invention, the track width is 6 μm or less, and the film thickness of the metal magnetic film core is 1.5 μm or more than the track width and not more than twice the track width. 2. The magnetic head according to claim 1, wherein the track is formed in a state where the pair of metal magnetic film cores are displaced from each other, and by increasing the thickness of the metal magnetic film core by 1.5 μm or more, The effect of increasing the head output is further increased.

  According to a sixth aspect of the present invention, the magnetic recording pattern track pitch of the magnetic recording / reproducing system used as a read-only head is 10 μm or less. When the track pitch is 10 μm or less, the effect of increasing the head output by shifting the track to increase the thickness of the metal magnetic film core is further increased.

  The invention according to claim 7 of the present invention is characterized in that the track pitch of the magnetic recording pattern of the magnetic recording / reproducing system used as a read-only head is 6 μm or less. When the head is a head and the track pitch is 6 μm or less, the effect of increasing the head output by shifting the track to increase the film thickness of the metal magnetic film core is further increased.

  The invention according to claim 8 of the present invention is the magnetic head according to any one of claims 1 to 7, characterized in that the metal magnetic film core is a laminated film of a metal magnetic film and an insulating film. By using a film, the frequency characteristics of the relative magnetic permeability of the metal magnetic film core can be enhanced.

  The magnetic head according to claim 9 of the present invention is characterized in that the metal magnetic film forming the metal magnetic film core is a nitride film mainly composed of Fe and Ta. By using a nitride film mainly composed of FeTa, the frequency characteristics of the relative magnetic permeability of the metal magnetic film core can be improved.

  According to a tenth aspect of the present invention, in the magnetic head according to the first to ninth aspects, when the track is formed by shifting the pair of metal magnetic film cores relative to each other, the marker is positioned at a position where the track is shifted by a predetermined amount. The magnetic head manufacturing method is characterized in that it is formed. By providing a marker, it is possible to accurately control the amount of track deviation.

  According to an eleventh aspect of the present invention, in the method of manufacturing a magnetic head according to the tenth aspect, the marker is formed with an insulating film thickness of 0.1 μm or more and 0.2 μm or less. In addition, by setting the film thickness of the insulating film as a marker to 0.1 μm or more and 0.2 μm or less, it is possible to control the amount of track deviation with high accuracy when performing track matching.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to FIGS. 1 to 4, but the present invention is not limited to these examples.

(Embodiment 1)
FIG. 1A is a diagram showing the configuration of the magnetic head according to the embodiment of the first invention, and FIG. 1B is an enlarged view of the vicinity of the gap on the tape running surface of the magnetic head.

As shown in FIG. 1A, in the magnetic head of the present invention, for example, a metal magnetic layer 1 made of FeTaN and an insulating film 2 made of SiO ₂ are laminated to form a metal magnetic film core 3 having a thickness of 10 μm. The metal magnetic film core 3 is sandwiched between non-magnetic substrates 4 made of, for example, calcium titanate ceramics to form magnetic core block halves 7a and 7b, and are joined and integrated through a magnetic gap 8. It has become. Reference numeral 9 denotes a winding window for winding a coil.

  As shown in the enlarged view of FIG. 1B, in the magnetic head of the present invention, the metal magnetic film cores 3 of the magnetic core block halves 7a and 7b are abutted via the magnetic gap 8, and the metal magnetic film cores of each other. 3 are joined in a state where the butt of 3 is intentionally shifted. At this time, the thickness of the metal magnetic film core 3 is 10 μm, and the track width 11 (here, the portion where the butt of the metal magnetic film core 3 overlaps) is 7 μm. 6 μm. Thus, the thickness of the metal magnetic film core 3 can be made larger than the track width by intentionally shifting the butt and providing the metal magnetic film core 3 with portions 12 and 13 that do not butt each other. It becomes. The magnetic core block 7 is a joined body of the metal magnetic film core 3 and the nonmagnetic substrate 4, and is constituted by, for example, joining using a sputtered film forming surface 5 on one side and a glass layer 6 on the other side.

  In addition, although the nitride film which made FeTa the main component was illustrated here as a metal magnetic film, soft magnetic characteristics, such as the nitride film of FeNbZr, the FeAlSi system magnetic film, and the amorphous alloy film which made Co the main component, are shown here. As long as the material is excellent, it can be used, and the present invention is not limited thereto.

  In addition, although SiO2 is exemplified here as the insulating film, any other insulating film such as Al2O3 can be used, and the present invention is not limited thereto. In addition, as a non-magnetic substrate, a ceramic material based on calcium titanate is illustrated here, but other than this, a ceramic material mainly composed of titanium oxide, magnesium oxide and nickel oxide, and MnZn ferrite as a main component are oxidized to this. Examples include non-magnetic ferrite-based materials to which titanium or the like is added, but the present invention is not limited to these.

  FIG. 2 shows the relationship between the thickness of the metal magnetic film core and the head output of a magnetic head having a track width of 8 μm constructed according to the embodiment of the present invention. Here, an experiment was performed using magnetic heads having various metal magnetic film core thicknesses, with the butt shift width being changed so that the track width was 8 μm. In the measurement, a so-called MIG head (track width: 6 μm, gap length: 0.20 μm) was used as the recording head, and the head output was evaluated using the magnetic head of the present invention as the reproducing head. As specifications of the reproducing head, the track width is 8 μm, the gap depth is 10 μm, and the gap length is 0.16 μm. Here, the gap length is defined as a gap length at which a swept signal having a different frequency is recorded on a magnetic tape, and a so-called null point value at which the reproduction output signal becomes zero. The measurement was performed using MP tape. The relative speed of the tape and the head was 15 m / s, and the measurement frequency was 30 MHz. In FIG. 2, the horizontal axis represents the difference between the thickness of the metal magnetic film core and the track width, the vertical axis represents the head output, and the head output represents the head output when the thickness of the metal magnetic film core is 8 μm as 0 dB. The relative value with respect to was evaluated.

  From the results of FIG. 2, it was found that when the thickness of the metal magnetic film core is about 1.5 μm larger than the track width, the head output is +1 dB, and when it is 2.0 μm larger, the head output is +1.5 dB. . It is determined that there is an effect when the head output is +1 dB, and a large effect when the head output is +1.5 dB.

  FIG. 3 shows the relationship between the thickness of the metal magnetic film core and the head output of a magnetic head having a track width of 6 μm constructed according to the embodiment of the present invention. Here, an experiment was performed using magnetic heads having various metal magnetic film core thicknesses, with the butt shift width being changed so that the track width was 6 μm. In the measurement, a so-called MIG head (track width: 5 μm, gap length: 0.20 μm) was used as the recording head, and the head output was evaluated using the magnetic head of the present invention as the reproducing head. As specifications of the reproducing head, the track width is 6 μm, the gap depth is 10 μm, and the gap length is 0.16 μm. Here, the gap length is defined as a gap length at which a swept signal having a different frequency is recorded on a magnetic tape, and a so-called null point value at which the reproduction output signal becomes zero. The measurement was performed using MP tape. The relative speed of the tape and the head was 15 m / s, and the measurement frequency was 30 MHz. In FIG. 2, the horizontal axis is the difference between the thickness of the magnetic metal film core and the track width, the vertical axis is the head output, and the head output is the head output when the thickness of the metal magnetic film core is 6 μm. The relative value with respect to was evaluated. From the results of FIG. 3, it can be seen that the head output is +1.1 dB when the thickness of the metal magnetic film core is about 1.0 μm larger than the track width, and the head output is +1.6 dB when the thickness is 1.5 μm. all right.

  FIG. 4 is a diagram illustrating an example of a method of manufacturing the magnetic head represented in the embodiment of the present invention, and is an enlarged view in the vicinity of the gap on the tape running surface of the magnetic head. When joining the magnetic core block half body 7 and the metal magnetic film core 3 with the magnetic gap 8 being shifted from each other, the marker is used to accurately control the amount of butt deviation. When manufacturing a magnetic head with a metal magnetic film core thickness of 10 μm and a track width of 7.5 μm, a 0.1 μm thick SiO 2 film 2 as a marker is formed on the metal magnetic film core at a pitch of 2.5 μm. To do. When adjusting the butting of the metal magnetic film core through the gap, the position is adjusted so that the marker of the SiO 2 film 2 and the end of the metal magnetic film core abut. By such a magnetic head manufacturing method, the track misalignment portions 12 and 13 are provided on both sides of the track width of 2.5 μm, and the track width 11 where the butt of the metal magnetic film core overlaps is accurately set to 7.5 μm. It becomes possible to do so.

  When a magnetic recording / reproducing system such as a digital VTR or a data streamer is used in the magnetic recording / reproducing system of the present invention, if high-density recording further proceeds, or if a head characteristic at a high frequency is required. However, the present invention can also be applied to a read-only magnetic head used in these systems and a manufacturing method thereof.

1 is a perspective view of a magnetic head and an enlarged view of the vicinity of a gap on a tape running surface according to Embodiment 1 of the present invention; FIG. Comparison of head output Comparison of head output The figure of the manufacturing method of the magnetic head of an embodiment of the invention A perspective view of a conventional magnetic head and an enlarged view of the vicinity of the gap on the tape running surface of the conventional magnetic head

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Metal magnetic film 2 Insulating film 3 Metal magnetic film core 4 Nonmagnetic board | substrate 5 Sputtered film formation surface 6 Glass layer 7 Magnetic core block half body 8 Magnetic gap 9 Winding window 11 Track width 12 Butt | deviation shift | offset | difference part 13 Butt | offset deviation part 21 Metal Magnetic film 22 Insulating film 23 Metal magnetic film core 24 Nonmagnetic substrate 25 Magnetic core block half 26 Glass layer 28 Magnetic gap 29 Winding window

Claims (11)

In a magnetic head used as a read-only head with a structure in which a metal magnetic film core is sandwiched between nonmagnetic substrates, a pair of magnetic core block halves in which the metal magnetic film core is sandwiched between nonmagnetic substrates protrudes through a gap. The track width is 10 μm or less, and the film thickness of the metal magnetic film core is 2 μm or more than the track width, where the track width is defined as the track width. A magnetic head having a film thickness not more than twice the track width and having a pair of metal magnetic film cores shifted from each other. The track width is 8 μm or less, the film thickness of the metal magnetic film core is 1.5 μm or more and twice or less the track width, and the pair of metal magnetic film cores are shifted from each other. 2. The magnetic head according to claim 1, wherein a track is formed. When the track width is 8 μm or less, the thickness of the metal magnetic film core is 2.0 μm or more and twice or less the track width, and the pair of metal magnetic film cores are displaced from each other 2. The magnetic head according to claim 1, wherein a track is formed. The track width is 6 μm or less, the film thickness of the metal magnetic film core is 1.0 μm or more and twice or less the track width, and the pair of metal magnetic film cores are shifted from each other. 2. The magnetic head according to claim 1, wherein a track is formed. The track width is 6 μm or less, the film thickness of the metal magnetic film core is 1.5 μm or more and twice or less the track width, and the pair of metal magnetic film cores are shifted from each other. 2. The magnetic head according to claim 1, wherein a track is formed. 6. The magnetic head according to claim 1, wherein a track pitch of a magnetic recording pattern of a magnetic recording / reproducing system used as a reproducing-only head is 10 [mu] m or less. 6. A magnetic head according to claim 1, wherein a track pitch of a magnetic recording pattern of a magnetic recording / reproducing system used as a reproducing-only head is 6 [mu] m or less. 8. A magnetic head according to claim 1, wherein the metal magnetic film core is a laminated film of a metal magnetic film and an insulating film. 9. The magnetic head according to claim 1, wherein the metal magnetic film forming the metal magnetic film core is a nitride film mainly composed of Fe and Ta. 10. A method of manufacturing a magnetic head according to claim 1, wherein when the track is formed by shifting the pair of metal magnetic film cores from each other, the marker is formed at a position where the track is shifted by a predetermined amount. . 11. The method of manufacturing a magnetic head according to claim 10, wherein the marker is formed with a thickness of the insulating film of 0.05 μm or more and 0.2 μm or less.

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