JPH07169021A - Thin film magnetic head - Google Patents

Abstract

PURPOSE:To reduce the reproduced waveform interference when a line recording density is high by constituting the magnetic layer of a thin film magnetic head with a layer-built body composed of two magnetic films having different polishing characteristics. CONSTITUTION:A magnetic layer 19 has a layer-built structure which is composed of a first magnetic film 43 and a second magnetic film 45 which has polishing characteristic different from that of the first magnetic film 43 and is built up on the outer side of the first magnetic film 43. Two such magnetic layers 19 are provided with a magnetic gap 23 in between. The first magnetic film 43 is made of CoZnNb-based amorphous material and the second magnetic film 45 is made of FeNi alloy. The second magnetic film 45 is shaved off so that its surface retreats from a sliding plane 47 and, by the influence of the retreat, the end parts of the first magnetic film 43 are selectively shaved to form smooth curves and the distribution of the invasion of fluxes from the end parts is spread to reduce a false output. By composing the magnetic layer of a thin film magnetic head of the layer-built structure of the first and second magnetic films having different polishing characteristics, the smooth curves are formed on the end parts of the magnetic layer, so that a false output such as an undershoot can be suppressed and a peak-shift can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film magnetic head used in a magnetic disk device used as an external storage device such as a computer.

[0002]

2. Description of the Related Art A magnetic disk device that rotates a magnetic disk having a magnetic recording film on its surface and performs recording / reproducing using a magnetic head is widely used as an external storage device such as a computer. 2. Description of the Related Art In recent years, with an increase in recording frequency due to an increase in storage capacity and a narrower track, the importance of a thin film magnetic head formed by using a thin film forming technique such as sputtering or plating is increasing.

The inductive type thin film magnetic head has a shape as shown in FIG. 2, the head element 13 is formed on the rear end surface of the slider 11 by a thin film process, and the sliding surface 47 is as shown in the process of FIG. After cutting the substrate 15, the rail is processed and then polished. The cross section of the head element 13 has the structure shown in FIG. 3, and the head element 1 is formed on a base layer 17 such as Al ₂ O ₃ deposited on the substrate 15.
3 are stacked. In the head element 13, the magnetic layer 19 is formed so as to sandwich the coil 25, which is a magnetic flux detecting element, with the interlayer insulating layer 21 interposed therebetween. Further, the head element 13 is protected by a protective layer 27 such as Al ₂ O ₃ .
Further, the magnetic flux picked up from the magnetic disk by the magnetic gap 23 provided in the magnetic layer 19 interlinks with the coil 25,
An output is obtained by the change in the interlinkage magnetic flux.

The output obtained from one magnetization reversal recorded on the magnetic disk from the thin film magnetic head is as shown in FIG. 4, and undershoots 31 occur on both sides of the main output 29. For this reason, when the linear recording density increases, the undershoot 31 interferes with the main output 29, causing a so-called peak shift in which the peak position of the main output 29 moves on the time axis, which increases the read error rate. Let Further, as shown in FIG. 5, undulation occurs in the linear recording density dependence of the output. In order to correct this undulation, a waveform equivalent circuit that cancels the undershoot 31 is inserted in the reproducing circuit of the magnetic disk device to reduce the effect of the undershoot 31.

In the thin film magnetic head, one of the causes of the undershoot 31 is called a contour effect depending on the shape of the magnetic head. This will be described with reference to FIG. FIG. 6 is a schematic diagram showing the process of reproducing one magnetization reversal 33 recorded on the magnetic disk over time. The magnetic disk progresses from the right side to the left side of the drawing, the magnetization reversal 33 reaches the end of the magnetic layer 19 on the right side of the head element 13 (time t = t0), and the magnetic flux that has not flowed in the magnetic layer up to that point is generated. Since the coil 25 interlinks with the coil 25, an undershoot 31 occurs. Subsequently, when the magnetization reversal 33 passes through the magnetic gap 23, the flow direction of the magnetic flux suddenly changes, so that the main output 29 is generated (time t =
t1). Finally, when the magnetization reversal 33 leaves the end portion of the magnetic layer 19 on the left side, the magnetic flux that has been linked to the coil 25 does not flow until then, and the undershoot 31 occurs. As described above, it is known that the undershoot 31 is generated by the flow of magnetic flux at both ends of the magnetic layer 19.

A thin film magnetic head of a type other than the inductive thin film magnetic head, for example, a shield type magnetoresistive effect thin film magnetic head using a magnetoresistive effect element (hereinafter referred to as an MR element) and an inductive thin film magnetic head. A pull-in type magnetoresistive effect thin film magnetic head that is a type that picks up a magnetic flux from a magnetic gap, and a single magnetic pole thin film magnetic head that is used for perpendicular recording and performs recording / reproduction by a main magnetic pole and uses a return magnetic pole as a return path. Also in
Similarly, since a magnetic flux flows in and out from the end of the magnetic layer to generate a pseudo output waveform corresponding to the undershoot of the inductive thin film magnetic head, its influence is reduced by a waveform equivalent circuit or the like.

[0007]

In the prior art, as described above, a waveform equivalent circuit for canceling a pseudo output waveform such as an undershoot must be inserted in the reproducing circuit, and therefore, the constituent circuit of the magnetic disk device. There was a problem that became complicated. Further, since the pseudo output position and the waveform change due to the dimension of the thin film magnetic head in manufacturing and the variation of the flying height, it is difficult to appropriately set the parameters of the waveform equivalent circuit for all devices. As a result, the error rate was deteriorated.

To solve these problems, the object of the present invention is to reduce the pseudo output waveform such as undershoot,
An object of the present invention is to provide a thin film magnetic head that is less affected by waveform interference.

[0009]

In order to achieve the above-mentioned object, the present invention is a magnetic layer of a thin film magnetic head comprising two kinds of magnetic films having different polishing characteristics with a magnetic gap interposed therebetween.
By sequentially stacking the first magnetic film and the second magnetic film, the end portion of the second magnetic film is retracted from the sliding surface of the slider depending on the polishing characteristics. The end portion of the magnetic film is characterized in that a smooth curved surface is formed on the contact surface side with the second magnetic film depending on the polishing characteristics.

[0010]

[Operation] A flow chart of the machining process of the thin film magnetic head is shown in FIG.
0 will be described as an example. By polishing the slider sliding surface in the manufacturing process, the end portion of the second magnetic film having low polishing characteristics is scraped more than the sliding surface, so that a step is formed between the slider and the first magnetic film. Furthermore, since the end of the first magnetic film on the contact surface side is selectively shaved, a smooth curve is formed at the corner of the end according to the polishing characteristics. This improves the shape effect depending on the shape of the thin film magnetic head. More specifically, as compared with the change in the interlinking magnetic flux of the conventional thin film magnetic head shown in FIG. 8, in the thin film magnetic head of the present invention, the interlinking magnetic flux change due to the entry and exit from the magnetic layer end is gentle as shown in FIG. Due to the curve, the pseudo output such as undershoot is inevitably small.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of an inductive thin film magnetic head using the present invention. The magnetic layer 19 is a laminated body in which a first magnetic film 43 and a second magnetic film 45 having different polishing characteristics are sequentially laminated outside the first magnetic film 43 with the magnetic gap 23 interposed therebetween. CoZrNb-based amorphous is used for the first magnetic film 43, and FeNi alloy is used for the second magnetic film 45. The hardness of each material is shown in Table 1.

[Table 1]

FIG. 10 is an enlarged view of the main part of the magnetic gap portion of this embodiment. The second magnetic film 45 is scraped and retracted from the sliding surface 47, and the effect is that the end of the first magnetic film 43 is selectively shaved to form a smooth curve, and the magnetic flux from the end is removed. The penetration distribution is widened and the pseudo output is reduced. FIG. 11 shows the linear recording density dependence of the output from the thin film magnetic head. The characteristic according to the present embodiment is shown by a solid line, and the characteristic by a conventional thin film magnetic head having substantially the same size and shape is shown by a broken line. The characteristics of the thin film magnetic head of the present invention show almost no undulation, which indicates that waveform interference due to pseudo output is small. In this embodiment, a FeNi alloy, which is a magnetic material, is used as the second magnetic film 45.
The same effect can be obtained by using a non-magnetic material such as u.

FIG. 12 shows an embodiment of a shield type magnetoresistive effect thin film magnetic head to which the present invention is applied. The MR element 35 is sandwiched between the first magnetic film 43 on the inner side and the second magnetic film 43 on the outer side.
Of the magnetic film 45. First magnetic film 4
3. As the second magnetic film 45, the above-mentioned materials are used. The details of the peripheral portion of each magnetic film are the same as in the previous embodiment, and the distribution of the penetration of the magnetic flux from the end portion is widened to reduce the pseudo output.

Further, the pull-in type magnetoresistive effect type thin film magnetic head and the single magnetic pole thin film magnetic head used for perpendicular magnetic recording have the same structure, and the distribution of the penetration of the magnetic flux from the end portion is widened to give a pseudo output. Is decreasing.

[0015]

As is apparent from the above description, according to the present invention, the magnetic layer of the thin film magnetic head is a laminated body of the first magnetic film 43 and the second magnetic film 45 having different polishing characteristics. By forming a smooth curve at the end of the magnetic layer, the shape effect is improved, and pseudo output such as undershoot can be reduced.Therefore, reproduction waveform interference at high linear recording density can be reduced and peak shift can be reduced. There is an effect that it can be reduced. Further, since it is possible to reduce the fluctuation of the pseudo output due to the variation of the size and the flying height of the magnetic head, it is possible to provide a magnetic disk device having stable characteristics. Further, since the pseudo output is reduced, it is not necessary to use a waveform equivalent circuit in the reproducing circuit of the magnetic disk device, and the circuit system is simplified, so that the magnetic disk device can be downsized and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of the present invention, and is a cross-sectional view of a main part of a head element portion of an inductive thin film magnetic head.

FIG. 2 is a schematic view showing the overall shape of a conventional thin film magnetic head.

FIG. 3 is a cross-sectional view of a main part of a head element portion of a conventional induction type thin film magnetic head.

FIG. 4 is an explanatory diagram showing a conventional technique, showing an output waveform of an inductive thin film magnetic head obtained from one magnetization reversal of a magnetic disk.

FIG. 5 is an explanatory diagram showing a conventional technique, and is a diagram showing the linear recording density dependence of the output of the inductive thin film magnetic head.

FIG. 6 is an explanatory diagram illustrating a conventional technique, and is a schematic diagram illustrating a mechanism in which an undershoot occurs in the output of the inductive thin film magnetic head.

FIG. 7 is a flowchart showing a machining process of the thin film magnetic head.

FIG. 8 is an explanatory diagram illustrating a conventional technique, and is a schematic diagram showing an interlinkage magnetic flux and an output of a coil of an inductive thin film magnetic head.

FIG. 9 is an explanatory diagram for explaining the operation of the present invention, and is a schematic diagram showing the interlinkage magnetic flux and the output of the coil of the inductive thin film magnetic head.

FIG. 10 is an explanatory view showing an embodiment of the present invention, and is an enlarged cross-sectional view of a main part of a magnetic gap portion of the inductive thin film magnetic head.

FIG. 11 is an explanatory diagram illustrating an embodiment of the present invention,
It is a diagram showing the linear recording density dependence of the output of the induction type thin film magnetic head.

FIG. 12 is an explanatory view showing an embodiment of the present invention, and is a cross-sectional view of a main part of an element part of a shield type magnetoresistive thin film magnetic head.

[Explanation of symbols]

 11 Slider 13 Head Element 15 Substrate 17 Underlayer 19 Magnetic Layer 21 Interlayer Insulating Layer 23 Magnetic Gap 25 Coil 27 Protective Layer 35 Magnetoresistive Effect Element 43 First Magnetic Film 45 Second Magnetic Film 47 Sliding Surface

Claims (2)

[Claims] 1. A thin film coil or a magnetoresistive effect type (M
R) A head composed of a thin film inductive or MR type detecting element for detecting writing or magnetic flux change, and a magnetic layer sandwiching the detecting element with an interlayer insulating layer and having a magnetic gap at a predetermined interval. A thin-film magnetic head of a magnetic disk device, which comprises an element and a slider in which the head element is disposed on a rear end surface and slides on a magnetic disk surface, and the sliding surface of the slider is polished. The magnetic layer is made of two kinds of magnetic films having different polishing characteristics, and the first magnetic film and the second magnetic film are sandwiched by the magnetic gap.
Magnetic films are sequentially stacked, the end of the second magnetic film is recessed from the sliding surface of the slider depending on the polishing characteristics, and the end of the first magnetic film is the slider. The thin-film magnetic head is characterized in that it has a smooth curved surface that is the same as the sliding surface of (1) and that depends on the polishing characteristics. 2. The thin-film magnetic head according to claim 1, wherein the first magnetic film is made of a CoZr-based amorphous alloy, and the second magnetic film is made of FeNi.