JP2008234784A - Magnetic head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic head which has a large head output by lowering magnetic resistance of a magnetic path. <P>SOLUTION: The magnetic head is provided with: magnetic core half bodies where a magnetic film core obtained by alternately laminating a plurality of magnetic films 1a and 1b is sandwiched by non-magnetic substrates, the magnetic core half bodies being joined to each other; sliding surfaces 9 formed at parts of the magnetic core half bodies which face a magnetic recording medium; and a magnetic gap 8 formed in an area coming in contact with the sliding surfaces 9 between a pair of magnetic core half bodies. A first axis of hard magnetization 10a is formed in at least one magnetic film 1a between the plurality of magnetic films in a direction inclined from the depth direction of a magnetic gap 8, and a second axis of hard magnetization 10b is formed in the second magnetic film 1b different from the first magnetic film 1a among the magnetic films in a direction inclined opposite to the direction where the first axis of hard magnetization 10a is formed from the depth direction of the magnetic gap 8. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

  In recent years, magnetic recording apparatuses such as digital VTRs and tape 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 that records and reproduces a large amount of information, a magnetic recording medium having a high coercive force is used by applying metal powder or a metal vapor deposition film. In order to enable reading and writing of information with respect to such a magnetic recording medium, it is desired to develop a magnetic head having a high saturation magnetic flux density and excellent characteristics in a high frequency band of several tens of MHz or more. In order to respond to such demands, magnetic film cores are formed by alternately laminating magnetic films such as Sendust, amorphous magnetic alloy, and FeTaN and insulating films, and both sides of the magnetic film cores are sandwiched between nonmagnetic substrates. A laminated magnetic head having a structure and improved high-frequency characteristics has been developed.

FIG. 7 is a perspective view showing an example of a conventional laminated magnetic head. The magnetic head is formed by combining a first magnetic core half body 107a and a second magnetic core half body 107b configured by sandwiching a magnetic film core 103 with a nonmagnetic substrate 104. The magnetic gap 108 is a gap formed between the first magnetic core half 107a and the second magnetic head core half 107b. In the magnetic film core 103, for example, magnetic films 101 made of FeTaN and insulating films 102 made of SiO ₂ films are alternately stacked. The nonmagnetic substrate 104 is made of, for example, calcium titanate ceramics.

  The sliding surface 109 faces the recording surface of the magnetic recording medium when reading information recorded on the magnetic recording medium. A winding window 105 is formed between the first magnetic core half 107a and the second magnetic core half 107b. Each of the first magnetic core half body 107a and the second magnetic core half body 107b is formed with a coil (not shown) in which a conductive wire is wound through the winding window 105. This coil outputs a change in magnetic flux passing through the magnetic head as a change in voltage when the magnetic head scans the recording surface of the magnetic recording medium.

  In the laminated magnetic head, the output of the magnetic head is greatly affected by the magnetic permeability of the magnetic film core, and the higher the magnetic permeability, the higher the head output. The first magnetic head has a configuration in which the direction of the hard axis of the magnetic film is oriented perpendicular to the magnetic gap in order to increase the head output at high frequency (see, for example, Patent Document 1).

  In addition, the second magnetic head has a configuration in which a magnetic film in which the direction of the hard axis is parallel to the magnetic gap and a magnetic film in the vertical direction are stacked (for example, see Patent Document 2).

In addition, the third magnetic head has a configuration in which the magnetic axis of the magnetic film is different for each magnetic film, and the magnetic core as a whole becomes a magnetic isotropic film (see, for example, Patent Document 3).
JP 7-65316 A Japanese Patent Laid-Open No. 10-320710 JP-A-2-302908

  However, in the case of the first and second magnetic heads, when considering the shortest magnetic path of the magnetic head, the direction of the hard axis of magnetization having a small magnetic resistance is not necessarily the shortest direction of the magnetic path. For this reason, the output of the magnetic head cannot be further increased.

  Further, when an isotropic magnetic film is formed by combining magnetic films having anisotropy as in the third magnetic head, the permeability value is lowered particularly in a high frequency band. For this reason, the magnetic resistance increases and the output of the magnetic head cannot be increased.

  SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and an object thereof is to provide a magnetic head that can increase the head output by reducing the magnetic resistance of the magnetic path.

  The magnetic head of the present invention includes a magnetic core half in which a plurality of magnetic films and insulating films are alternately stacked and sandwiched between nonmagnetic substrates and bonded together, and the magnetic core half A sliding surface formed at a portion facing the magnetic recording medium; and a magnetic gap formed in a region in contact with the sliding surface between the pair of magnetic core halves. In order to solve the above problem, at least one first magnetic film of the plurality of magnetic films has a first hard axis of magnetization in a direction inclined from the depth direction of the magnetic gap, Of these, the second magnetic film different from the first magnetic film has a second hard magnetization axis in a direction inclined from the depth direction of the magnetic gap to a direction opposite to the direction in which the hard magnetization axis is formed. Is formed.

  According to the present invention, it is possible to reduce the magnetic resistance of the magnetic path and increase the head output by arranging the hard magnetization axis of the magnetic film in parallel with one side of the outer periphery of the winding window that is in contact with the magnetic gap. A magnetic head that can be provided can be provided.

  The magnetic head of the present invention has a winding window formed in a region in contact with the magnetic gap between the pair of magnetic core halves, and is in contact with the magnetic gap in an outer peripheral surface of the winding window. Two surfaces are formed to be inclined in opposite directions with the magnetic gap interposed therebetween, and the first hard axis is formed along one of the two surfaces in contact with the magnetic gap. The shaft may be formed along the other surface of the two surfaces in contact with the magnetic gap.

  Further, the magnetic film may be configured such that the first magnetic film and the second magnetic film have the same number.

  Further, the first magnetic film and the second magnetic film may be a nitride film mainly composed of Fe and Ta.

  The first magnetic film and the second magnetic film may have a thickness of 0.10 μm or more and 0.50 μm or less per layer. With this configuration, the head output can be further increased.

  Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 to 6, but the present invention is not limited to these embodiments.

(Embodiment)
FIG. 1 is a perspective view showing a configuration of a magnetic head according to an embodiment of the present invention. The magnetic head is formed by bonding a first magnetic core half body 7a and a second magnetic core half body 7b, which are configured by a nonmagnetic substrate 4 sandwiching a magnetic film core 3. In the magnetic film core 3, for example, magnetic films 1 made of FeTaN and insulating films 2 made of SiO ₂ are alternately stacked. The film thickness of the magnetic film core 3 is, for example, 8 μm. The magnetic film 1 has anisotropy with respect to how it is magnetized, and has a hard axis that is hard to be magnetized and an easy axis that is easily magnetized. The hard magnetization axis has higher permeability than the easy magnetization axis. The nonmagnetic substrate 4 is formed of, for example, calcium titanate ceramics.

  The sliding surface 9 faces the magnetic recording medium when the magnetic head reads information from the magnetic recording medium. The magnetic gap 8 is a gap formed between the first magnetic core half body 7 a and the second magnetic core half body 7 b provided in a region in contact with the sliding surface 9. When the magnetic head is disposed on the magnetic recording medium, the magnetic flux on the recording surface of the magnetic recording medium flows from the first magnetic core half 7a (or the second magnetic core half 7b) of the magnetic gap 8, and the magnetic gap 8 out of the second magnetic core half 7b (or the first magnetic core half 7a).

  A winding window 5 is formed in contact with the magnetic gap 8 and between the first magnetic core half 7a and the second magnetic core half 7b. A conducting wire inserted through the winding window 5 is wound around each of the first magnetic core half body 7a and the second magnetic core half body 7b to form a coil (not shown). This coil outputs (head output) a change in magnetic flux flowing in from the first magnetic core half 7a or the second magnetic core half 7b as a change in voltage. The first inclined surface (outer peripheral surface) 6a is a surface in contact with the first magnetic core half 7a and the magnetic gap 8 at the outer peripheral portion of the winding window 5, and the second inclined surface (outer peripheral surface) 6b is the winding window. 5 is a surface in contact with the second magnetic core half body 7 b and the magnetic gap 8 in the outer peripheral portion. The first inclined surface 6a and the second inclined surface 6b are formed to be inclined to the opposite sides with respect to the depth direction of the magnetic gap 8 (the direction of arrow A in FIG. 1).

  FIG. 2 is a plan view showing the configuration of the magnetic film 1. In the magnetic film 1, the first magnetic film 1 a shown in FIG. 2A and the second magnetic film 1 b shown in FIG. 2B are alternately stacked with the insulating film 2 interposed therebetween. As shown in FIG. 2A, the first magnetic film 1a has a first hard magnetization axis 10a formed in parallel to the first slope 6a. In the second magnetic film 1b, as shown in FIG. 2B, the second hard axis 10b is formed in parallel to the second inclined surface 6b.

  The first magnetic film 1a and the second magnetic film 1b are not necessarily stacked alternately with the insulating film 2 interposed therebetween. For example, the first magnetic film 1a, the first magnetic film 1a, the second magnetic film 1b, and the second magnetic film 1b may be stacked in this order with the insulating film 2 interposed therebetween.

  FIG. 3 is a plan view showing the flow of magnetic flux when information is read from the magnetic recording medium using the magnetic head. The magnetic flux 12 generated in the magnetic recording medium 11 such as a magnetic tape enters the first magnetic core half 7 a or the second magnetic core half 7 b from the magnetic gap 8 and flows in a loop shape with respect to the winding window 5. ing.

In order to increase the output of the magnetic head, it is necessary to increase the amount of magnetic flux passing through the magnetic film 1. In order to increase the amount of magnetic flux, the magnetic resistance of the magnetic film 1 may be lowered. Magnetoresistance is
R = L / (μ × S) (Formula 1)
It is expressed as In Equation 1, R is the magnetic resistance, L is the length, μ is the magnetic permeability, and S is the cross-sectional area. In the magnetic film 1, the vicinity of the magnetic gap 8 in contact with the sliding surface 9 (region near the gap) has a smaller cross-sectional area and a higher magnetic resistance than other regions. By reducing the magnetic resistance in the vicinity of the gap, the magnetic resistance of the entire magnetic head is lowered.

  That is, as shown in the first magnetic film 1a, when the first hard axis 10a is formed in the direction of the magnetic flux in the vicinity of the gap, the hard axis is formed perpendicular to the magnetic gap. The magnetic resistance becomes smaller than that. Therefore, the amount of magnetic flux flowing from the conventional magnetic head increases, the amount of change in magnetic flux increases, and the head output increases.

  In addition, although the nitride film which has FeTa as a main component was illustrated as a magnetic film, it was excellent in soft magnetic characteristics, such as the nitride film of FeNbZr, the FeAlSi type | system | group magnetic film, and the amorphous alloy film which has Co as a main component besides this. Any material can be used, and the present invention is not limited to these.

In addition, although the SiO ₂ film has been exemplified as the insulating film, any other insulating film such as Al ₂ O ₃ can be used, and the present invention is not limited to these. Absent.

  In addition, as a non-magnetic substrate, a ceramic material based on calcium titanate has been exemplified, but in addition to this, a ceramic material mainly composed of titanium oxide, magnesium oxide and nickel oxide, and MnZn ferrite as a main component and titanium oxide. And the like, but the present invention is not limited to these.

  FIG. 4 shows a conventional magnetic head (B) in which the hard axis direction is perpendicular to the magnetic gap with respect to the head output of the magnetic head (A) configured in the embodiment of the present invention. 5 is a graph in which the head output of each of the conventional magnetic head (C) and the respective head outputs is actually measured when isotropic magnetic films are combined. The horizontal axis is the measurement frequency.

  The measurement conditions were that the magnetic head had a track width of 8 μm, a gap depth of 10 μm, a gap length of 0.16 μm, and the thickness of the magnetic film per layer was 0.25 μm. The magnetic recording medium used for the measurement is an MP (Metal Particle) tape. The relative speed of the tape and the magnetic head is 15 m / s. From FIG. 4, it was found that when the magnetic head (A) of the present invention was used, a higher output was obtained compared to the magnetic heads (B) and (C). That is, in the second magnetic film 1b shown in FIG. 2B, the magnetization difficult axis is almost perpendicular to the direction of the magnetic flux flow, the amount of magnetic flux decreases, and the head output decreases, but the second magnetic film 1b shown in FIG. The magnetic head using the magnetic film 1 formed by laminating the first magnetic film 1a and the second magnetic film 1b has a higher head output than the conventional magnetic head.

  Further, as shown in FIG. 4, it was found that the higher the frequency, the better the output of the magnetic head (A) than that of the magnetic heads (B) and (C).

  FIG. 5 is a graph showing the relationship between the thickness of the magnetic film per layer and the head output in the magnetic head according to the embodiment of the present invention. The horizontal axis of the graph is the thickness (μm) of the magnetic film per layer, and the vertical axis is the head output. The head output is shown as a relative value with respect to a head output of 0 dB when the thickness of the magnetic film per layer is 2 μm.

  As measurement conditions, the magnetic head has a track width of 8 μm, a gap depth of 10 μm, and a gap length of 0.16 μm. The magnetic recording medium used for the measurement is an MP tape. The relative speed of the MP tape and the magnetic head is 15 m / s, and the measurement frequency is 30 MHz.

  In FIG. 5, the horizontal axis represents the thickness (μm) of the magnetic film per layer, and the vertical axis represents the head output. The head output is shown as a relative value with respect to a head output of 0 dB when the thickness of the magnetic film per layer is 2 μm. From the result of FIG. 5, when the thickness of the magnetic film per layer is 0.1 to 0.5 μm, the head output is +1 dB or more.

  FIG. 6 is a side view showing a state in which the first magnetic film 1a is magnetostatically coupled to the other first magnetic film 1a. Arrow 13 indicates the direction of magnetization. The first magnetic films 1a (not shown, but the second magnetic film 1b is the same) are in a state of being magnetically connected as indicated by broken lines. As described above, the formation of the closed magnetic path stabilizes the magnetization, and the first magnetic film 1a and the second magnetic film 1b have a single magnetic domain structure and are less affected by shape anisotropy.

  In FIG. 5, when the thickness of the magnetic film is 0.1 to 0.5 μm, the first magnetic film 1a and the second magnetic film 1b have a single magnetic domain structure, and the magnetic permeability can be kept high up to the high frequency region. It is considered that a high head output could be obtained.

  As described above, the magnetic head of the present invention can increase the head output by including the magnetic film having the hard magnetization axis provided parallel to the slope of the winding window.

  The magnetic head of the present invention is not limited to the case where the hard magnetization axis is provided parallel to the slope of the winding window. For example, the orientation of the hard magnetization axis is perpendicular to the magnetic gap and the slope of the winding window. The same effect can be obtained as long as the angle between the two is equal to the direction parallel to the slope of the winding window.

  Furthermore, the direction of the hard axis is not necessarily defined by the direction of the slope of the winding window. In the region near the gap between the first magnetic film 1a and the second magnetic film 1b, if the first hard magnetization axis and the second hard magnetization axis are inclined to the opposite sides of the magnetic gap, the magnetoresistance is reduced. As a result, the head output increases.

  The present invention has an effect that the head output is large, and can be used as a magnetic head of a magnetic recording / reproducing system such as a digital VTR or a data streamer.

The perspective view which shows the structure of the magnetic head based on Embodiment of this invention. Top view showing hard axis of magnetization in magnetic film of magnetic head Top view showing the flow of magnetic flux of the magnetic head Graph showing the head output result of the magnetic head The graph which shows the relationship between the thickness of the magnetic film per layer of the magnetic head which concerns on embodiment of this invention, and head output The side view which shows the state which the magnetic film of the magnetic head concerning embodiment of this invention couple | bonded magnetostatically A perspective view showing a configuration of a conventional magnetic head

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Magnetic film 1a 1st magnetic film 1b 2nd magnetic film 2 Insulating film 3 Magnetic film core 4 Nonmagnetic board | substrate 5 Winding window 6a 1st slope 6b 2nd slope 7a 1st magnetic core half body 7b 2nd magnetic core half body 8 Magnetic gap 9 Sliding surface 10a First hard axis 10b Second hard axis 11 Magnetic recording medium 12 Magnetic flux 13 Direction of magnetization

Claims (5)

A magnetic core half in which a plurality of magnetic films and insulating films are alternately stacked and sandwiched between nonmagnetic substrates and bonded together,
A sliding surface formed on a portion of the magnetic core half facing the magnetic recording medium;
In a magnetic head comprising a magnetic gap formed in a region in contact with the sliding surface between the pair of magnetic core halves,
At least one first magnetic film of the plurality of magnetic films has a first hard magnetization axis in a direction inclined from the depth direction of the magnetic gap,
Of the magnetic films, the second magnetic film different from the first magnetic film is oriented in a direction inclined from the depth direction of the magnetic gap to a direction opposite to the direction in which the first hard axis is formed. 2. A magnetic head characterized in that a hard axis is formed. A winding window formed in a region in contact with the magnetic gap between the pair of magnetic core halves;
Two of the outer peripheral surfaces of the winding window that are in contact with the magnetic gap are inclined to the opposite sides of the magnetic gap.
The first hard axis is formed along one of the two surfaces in contact with the magnetic gap,
The magnetic head according to claim 1, wherein the second hard axis is formed along the other surface of the two surfaces in contact with the magnetic gap.   3. The magnetic head according to claim 1, wherein the number of the first magnetic film and the second magnetic film is the same.   4. The magnetic head according to claim 1, wherein each of the first magnetic film and the second magnetic film is a nitride film containing Fe and Ta as main components.   5. The magnetic head according to claim 1, wherein the first magnetic film and the second magnetic film have a thickness of 0.10 μm to 0.50 μm per layer.

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