JPH02208805A - System for reproducing magnetic record - Google Patents

Abstract

PURPOSE:To obtain a reproducing output waveform with satisfactory symmetric property for positive and negative waveforms by adding reproducing output generated by an inductive voltage at a coil layer on the reproducing generated by a magneto- resistance effect element at the time of reproducing information on a magnetic recording medium recorded by the coil layer. CONSTITUTION:A recording and reproducing magnetic head 11 is structured in such a way that a first magnetic layer 14, the coil layer 16 sandwiched between a gap layer 16 and an inter-layer insulation layer 15, a second magnetic layer 17, and a protection layer 18 are laminated sequentially on a nonmagnetic substrate 12, and also, a thin film magneto-resistance effect element(thin film MR element) 19 is arranged in the gap layer 14. And the reproduction of the recording information of a confronting magnetic recording medium 20 by the thin film MR element 19 and that by the inductive voltage at the coil layer 16 are performed simultaneously by the magnetic recording and reproducing head 11. Since the phase of the reproducing output waveform 21 by the thin film MR element 19 is equivalent to that of the reproducing output waveform 22 by the coil layer 16, both reproducing output are synthesized at an adder circuit 23. Thereby, the symmetric property of positive and negative waveforms of a synthesized reproducing output waveform 24 can be improved, and the recording information can accurately be reproduced.

Description

[Detailed description of the invention] [Summary] A method for reproducing magnetically recorded information used in a magnetic disk device or a magnetic tape device, particularly a coil layer that generates a recording magnetic field in the magnetic pole gap portion and a reproduction-only magnet [Industrial application field] ] The present invention relates to a method for reproducing magnetically recorded information used in a magnetic disk device or a magnetic tape device, and particularly relates to a magnetic helad that is equipped with a coil layer that generates a recording magnetic field in the magnetic pole gap portion and a read-only magnetoresistive element. This paper relates to the magnetic recording reproduction method used.

In recent years, with the increase in the density of magnetic recording, there has been a demand for a recording/reproducing method that can stably obtain high output and good reproduced waveforms. The reproduction output of a magnetic head using a read-only thin film magnetoresistive element (hereinafter abbreviated as MR element) does not depend on the moving speed of the recording medium, so if the moving speed is particularly low, an inductive type using a coil layer is recommended. It is seen as promising as magnetic recording and reproducing devices become smaller because it is easier to obtain larger output than magnetic heads for recording and reproducing, but due to variations in the magnetic properties and shape of the MR element itself formed from a thin film, When reproducing information, it tends to be difficult to obtain a good reproduced waveform. Therefore, there is a need for a method that can obtain a good reproduction waveform when reproducing magnetically recorded information and can accurately reproduce the recorded information.

[Conventional technology]

In the conventional recording and reproducing method, for example, magnetic pole layers are arranged on both sides of a coil layer with an insulating layer between the eyebrows interposed therebetween, and a thin film magnetoresistive element (hereinafter abbreviated as MR element) is arranged in the gap between the tips of the two magnetic poles. When recording information on an opposing magnetic recording medium using a recording/reproducing magnetic head having a structure,
A signal current for recording information is applied to the coil layer of the magnetic head to magnetize the first and second magnetic pole layers, and recording is performed by a magnetic field leaking from the tips of the two magnetic pole layers sandwiching the gap layer. Conversely, when reproducing information recorded on a magnetic recording medium, the resistance value of the thin film MR element in the gap layer, which changes due to the leakage magnetic field from the medium, is detected as a voltage change to obtain a reproduction output. They share the task of writing and reading information to and from the magnetic recording medium.

[Problem to be solved by the invention]

By the way, when the thin film MR element in the conventional recording/reproducing magnetic head described above reproduces information recorded on a magnetic recording medium, the reproduced output waveform originally has positive and negative polarities centered on the 0■ line, as shown in FIG. Although a good waveform with a symmetrical waveform can be obtained, due to the magnetic properties of the thin film MR element itself and variations in the element shape due to patterning, variations in reproduction characteristics such as shifts in the optimum bias point are likely to occur. There are cases where the reproduced waveform has an asymmetrical positive and negative waveform around the Ov line as shown in FIG. This causes a problem in that a peak shift occurs in the reproduced waveform, making it difficult to accurately reproduce recorded information.

In view of the above-mentioned conventional problems, the present invention has been developed to solve the problem that, when reproducing information recorded on a magnetic recording medium using a recording/reproducing magnetic head using a thin film MR element, there is some variation in the magnetic properties, element shape, etc. of the thin film MR element. The object of the present invention is to provide a novel magnetic recording reproduction method that can obtain a reproduced output waveform with good symmetry between positive and negative waveforms.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a magnetic head equipped with a coil layer that generates a recording magnetic field in a magnetic pole gap portion for recording information on a magnetic recording medium, and a thin film magnetoresistive element dedicated to information reproduction. When reproducing information on a magnetic recording medium recorded by the coil layer, a reproduction output due to an induced voltage in the coil layer is added to a reproduction output by the magnetoresistive element.

[For production]

According to the present invention, when reproducing information recorded on a magnetic recording medium using a magnetic head including a coil layer that generates a recording magnetic field in a magnetic pole gap portion for recording information and a thin film MR element exclusively for reproducing information, In addition to reproduction using the thin film MR element, reproduction can be performed using the induced voltage in the coil layer that generates the recording magnetic field, and the reproduction output waveform is O■
Taking advantage of the fact that the positive and negative waveforms have good symmetry around the line, the reproduction output from the thin film MR element is combined with the reproduction output from the coil layer, which has good symmetry between the positive and negative waveforms. Even if the positive and negative waveforms of the re-main output waveform from the thin film MR element are asymmetrical due to variations in characteristics, element shape, etc., the degree of symmetry of the positive and negative waveforms of the composite reproducing output waveform is improved, and accurate reproduction of recorded information is possible. It becomes possible.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a longitudinal sectional view of a main part showing an example of a recording/reproducing magnetic head used in the magnetic recording/reproducing method according to the present invention.

In this embodiment, as shown in the figure, a coil layer 16, a second magnetic pole layer 17, and a protective layer 18 are sandwiched between a first magnetic pole layer 13, a gap layer 14, and an interlayer insulating layer 15 on a nonmagnetic substrate 12 serving as a slider. A thin film magnetoresistive element (hereinafter abbreviated as thin film MR element) 19 is laminated in this order and is disposed within the gap layer 14.
A recording/reproducing magnetic head 11 having a structure in which
The reproduction by the coil layer 16 and the reproduction by the induced voltage in the coil layer 16 are performed simultaneously.

At this time, since the reproduced output waveform 21 from the thin film MR element 19 and the reproduced output waveform 22 from the coil layer 16 are in the same phase as shown in FIG.
Synthesize in step 3.

In this way, for example, the positive and negative reproduction output values of the reproduction output waveform 21 by the thin film MR element 19 are set to a, respectively.

b. Let C be the positive or negative reproduction output value of the reproduction output waveform 22 by the coil layer 16, and let each positive or negative reproduction output value a
, b, c, a −0,8+ b = 1 +
When c=0.5, the positive/negative output ratio of the reproduced output waveform 21 from the thin film MR element 19 is a/b=0.
8, but the positive/negative reproduction output ratio of the composite reproduction output waveform 24 synthesized by the adding circuit 23 is (b + c)/(a
+c)=1.3/1°5-0.87, and the symmetry of the positive and negative waveforms of the composite reproduced output waveform 24 is improved. Therefore, recorded information can be accurately reproduced.

Further, FIG. 3 is a longitudinal cross-sectional view of a main part showing another example of a magnetic recording/reproducing head used in the magnetic recording/reproducing method according to the present invention, and parts equivalent to those in FIG. 1 are given the same reference numerals. .

In this embodiment, as shown in the figure, a thin film MR is formed on a magnetic substrate 42 which also serves as a magnetic shield, with a non-magnetic insulating layer 43 interposed therebetween.
A coil layer 16 on which the element 44 is disposed and sandwiched between the first magnetic pole layer 13, the gap layer 14, and the interlayer insulating layer 15;
A recording/reproducing magnetic head 41 having a structure in which a second magnetic pole layer 17 and a protective layer 18 are laminated in this order is used to oppose a magnetic recording medium 2.
The recorded information of 0 is simultaneously reproduced by the thin film MR element 44 and by the induced voltage in the coil IJ16.

In this case, since the thin film MR element 44 in the magnetic head 41 is provided between the magnetic substrate 42 outside the gap layer 14 and the first magnetic pole layer 13, the thin film MR element 44
A phase difference occurs between the reproduced output waveform 51 caused by the coil layer 16 and the reproduced output waveform 52 generated by the coil layer 16.

Therefore, as shown in FIG. 4, when the two reproduced outputs are combined in the adder circuit 23, the reproduced output from the thin film MR element 44 is sent to the delay circuit 53, and the phase with the reproduced output waveform 52 from the coil layer 16 is adjusted. After the adjustment, both reproduced outputs are combined by the adder circuit 23 to obtain a combined reproduced output waveform 54 with good symmetry between positive and negative waveforms. Such an embodiment also allows recorded information to be reproduced accurately.

Note that in the above embodiments, the running direction of the magnetic recording medium with respect to the magnetic head is explained as an example in which the magnetic recording medium runs in a direction from the thin film MR element side of the magnetic head to the magnetic scratching gap side. If the direction of media travel is reversed,
A delay circuit may be installed on the reproduction output side of the coil layer to adjust the phase of the reproduction output waveform.

(Effects of the Invention) As is clear from the above explanation, according to the magnetic recording reproducing method according to the present invention, the positive and negative waveforms of the reproduced output waveform by the thin film MR layer element become asymmetric due to variations in magnetic properties and shape. However, by combining the reproduced output waveform with good symmetry between positive and negative waveforms using the coil layer, a composite reproduced output waveform with good symmetry between positive and negative waveforms can be easily obtained, making it possible to accurately reproduce recorded information, etc. The practical effects are significant.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a main part showing an example of a magnetic head for recording and reproducing used in the magnetic recording reproducing method according to the present invention, and FIG. 2 is an explanation showing an embodiment of the magnetic recording reproducing method according to the present invention. 3 is a vertical sectional view of a main part showing another example of a magnetic head for recording and reproducing used in the magnetic recording reproducing method according to the present invention, and FIG. 4 is a longitudinal sectional view of another example of a magnetic recording reproducing method according to the present invention. FIG. 5 is a diagram showing an original normal reproduction output waveform of the thin film MR element; FIG. 6 is a diagram showing an asymmetric reproduction output waveform of positive and negative waveforms of the thin film MR element. 1 to 4, IL 41 is a magnetic head, 12 is a non-magnetic substrate, 13 is a first magnetic pole layer, 14 is a gap layer, 15 is an insulating layer between eyebrows, 16
17 is a coil layer, 17 is a second magnetic pole layer, 18 is a protective layer, 19.
44 is a thin film MR element W! Month B--1 Tahiha; Month 11
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Claims (1)

[Claims] A magnetic recording medium (20) includes a coil layer (16) that generates a recording magnetic field in a magnetic pole gap portion for recording information, and a thin film magnetoresistive element (19) dedicated to information reproduction. In the magnetic head (11), a magnetic recording medium (2) recorded by the coil layer (16) is provided.
0) When reproducing information on the magnetoresistive element (
19) A reproduction method for magnetic recording characterized in that a reproduction output due to an induced voltage in the coil layer (16) is added to the reproduction output obtained by the coil layer (16).