JP2863552B2 - Thin-film magnetic head and recording / reproducing apparatus using this thin-film magnetic head - Google Patents

Description

The present invention relates to a thin-film magnetic head and a recording / reproducing apparatus using the thin-film magnetic head.

(Prior Art) In recent years, with the increase in density and frequency of magnetic recording, a thin film magnetic head having a track width of about 10 μm has been required. In general, the output decreases as the track width decreases. This decrease in output can be compensated for by increasing the coercive force of the medium and increasing the number of turns of the coil. Therefore, the increase in coil resistance due to the decrease in coil wire width had to be dealt with by increasing the coil thickness.

Therefore, finer thin film processing technology is required,
There is a problem that the thin film magnetic head becomes expensive.

Therefore, it has been proposed to use a ring-type thin film magnetic head for recording and to use a magnetoresistive head different from the above-described thin film magnetic head for reproduction. In this case, it is possible to perform sufficient recording without increasing the number of coil turns by increasing the current at the time of recording. For reproduction, the magnetoresistive head detects a change in resistance due to a magnetic field leaking from the medium and performs reproduction.

 Each of such heads will be described with reference to the drawings.

FIG. 5 is a sectional perspective view showing an example of a thin-film magnetic head used at the time of recording.

In the figure, reference numeral 1 denotes a non-magnetic substrate. On this substrate 1, a first magnetic thin film 2 serving as a lower magnetic core is formed. A plurality of thin-film coils 3 are formed in a ring shape on the first magnetic thin film 2 by being insulated by an insulating film 4, and a magnetic gap is formed on the tip side of the first magnetic thin film 2. A non-magnetic thin film 5 is formed. Further, a second magnetic thin film 6 serving as an upper magnetic core is formed on the non-magnetic thin film 5 and the insulating film 4, and a protective film 7 is formed on the second magnetic thin film 6. Also, the first
A medium contact surface 8 is formed on an end surface where the second magnetic thin films 2 and 6 and the nonmagnetic thin film 5 are exposed.

In this head, a magnetic path is formed between the magnetic thin films 2 and 6 via a medium by passing a predetermined current, which is an output signal from a recording signal output unit (not shown), through the thin film coil 3. Thus, predetermined information is recorded on the medium.

FIG. 6 is a perspective view showing an example of a magnetoresistive head used at the time of reproduction.

In FIG. 1, reference numeral 11 denotes a magnetic thin film having a magnetoresistive effect formed on a non-magnetic substrate 12.
11 is formed of, for example, FeNi, CoNi, etc.
Uniaxial anisotropy is provided in the direction. The magnetic thin film 11
Are formed at both ends. Terminals 13, 14
, A DC power supply 16 is connected in series via a resistor 15, and a voltmeter 17 is connected in parallel.

When a magnetic field from the medium is applied in the direction of arrow B perpendicular to the direction of arrow A of the uniaxial anisotropy of the magnetic thin film 11, the resistance of the magnetic thin film 11 changes as shown in FIG. The change in resistance is detected by the voltmeter 17 and output as a reproduction signal. Normally, as shown in FIG. 7, the bias magnetic field Hb is applied, the external magnetic field and the resistance change are used almost linearly, and the saturation magnetic field Hs is reduced to reduce the demagnetizing field and improve the sensitivity. I do.

However, the above-described conventional magnetic head is composed of two heads, a thin-film magnetic head for recording and a magneto-resistive head for reproduction, and there is a problem that the installation space becomes large. Therefore, it is conceivable to stack them so as to be integrated, but in this case, there is a problem that the creation is very difficult.

(Problems to be Solved by the Invention) As described above, the conventional magnetic head is composed of two heads, a thin-film magnetic head for recording and a magnetoresistive head for reproduction, so that the installation space becomes large. However, when they are stacked so as to be integrated, there is a problem that the production is very difficult.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described conventional problems, and has as its object to provide a thin-film magnetic head that can be reduced in size with a simple configuration and that can improve recording efficiency and reproduction efficiency. I have.

[Structure of the Invention] (Means for Solving the Problems) In the thin-film magnetic head of the present invention, a non-magnetic thin film is formed on a part of the first magnetic thin film, and a ring-shaped thin-film coil is formed of an insulating film. Forming a second magnetic thin film on the non-magnetic thin film and on the insulating film;
A protective film is formed on the second magnetic thin film,
In a thin-film magnetic head in which a medium contact surface is formed on a surface where the end surfaces of the first and second magnetic thin films and the end surface of the non-magnetic thin film are exposed, at least one of the magnetic thin films has a magnetoresistance. A magnetoresistive thin film is formed by a magnetic material having an effect so as to act as a magnetic pole when recording information, and a thin film conductor for supplying a detection current is formed at both pole ends of the magnetoresistive effect thin film. .

Further, the thin film magnetic head of the present invention is characterized in that a ferromagnetic thin film is formed on both pole ends of the magnetoresistive thin film, and the magnetoresistive thin film is a single magnetic domain.

The recording / reproducing apparatus of the present invention, in the recording / reproducing apparatus using the above-described thin-film magnetic head, outputs a signal current corresponding to information to be recorded on the thin-film coil during recording, and outputs a bias current to the thin-film coil during reproducing. And a human input unit for inputting a reproduction signal, which is a change in the electric resistance of the magnetoresistive thin film during reproduction, from the thin film conductor.

(Function) In the thin-film magnetic head of the present invention, a magnetic material having a magneto-resistance effect is formed on at least one of the magnetic thin films on the medium contact surface so that the magneto-resistance effect thin film acts as a magnetic pole when information is recorded. Since the thin-film conductors for supplying the detection current are formed at both pole ends of the magnetoresistive effect thin film, the head can be reduced in size with a simple configuration.

Further, in the recording / reproducing apparatus of the present invention, an output section for outputting a signal current corresponding to information to be recorded on the thin-film coil at the time of recording and outputting a bias current to the thin-film coil at the time of reproduction, and an electric resistance of the magnetoresistive thin film at the time of reproduction. Input section for inputting the reproduction signal, which is a change in the current, from the thin-film conductor, so that it can be used as a thin-film magnetic head during recording, used as a magnetoresistive head during reproduction, and output a bias current to the thin-film coil during this reproduction. Therefore, recording efficiency and reproduction efficiency can be improved.

(Example) Hereinafter, an example of the present invention is described using a drawing.

1 and 2 are views showing a thin-film magnetic head according to an embodiment of the present invention, and FIG. 3 is a view for explaining a recording / reproducing apparatus using the thin-film magnetic head of FIG.

In these figures, reference numeral 21 denotes a non-magnetic substrate. On this substrate 21, a first magnetic thin film 22 serving as a lower magnetic core is formed. On the first magnetic thin film 22, a plurality of thin film coils 23 are formed in a ring shape insulated by an insulating film 24. Further, a non-magnetic thin film 25 serving as a magnetic gap is formed on the front end side of the first magnetic thin film 22. Further, a second magnetic core serving as an upper magnetic core is formed on the insulating film 24.
Is formed on the non-magnetic thin film 25.
The magnetoresistive magnetic thin film 27 is formed of a magnetic material having a magnetoresistive effect, such as FeNi or CoNi. Terminals 28 and 29 are formed on both sides of the magnetoresistive magnetic thin film 27, and lead wires 30 and 31 which are thin film conductors are connected to these terminals 28 and 29. Then, a protective film 32 is formed on the magnetoresistive magnetic thin film 27 and the second magnetic thin film 26. In addition, the first and second magnetic thin films 22,
The end face where the non-magnetic thin film 25 and 26 are exposed has a medium contact surface 33.
Are formed.

As shown in FIG. 3, each end of the thin-film coil 23 is connected to a switching circuit 34. The switching circuit 34 connects a recording signal output circuit 35 at the time of recording, and a bias current output circuit 36 at the time of reproduction. Connect.

The leads 30 and 31 are connected to a DC power supply circuit 37 and a reproduction signal input circuit 38, respectively.

In the thin-film magnetic head, during recording, a predetermined current which is an output signal from the recording signal output circuit 35 is switched by the switching circuit.
The magnetic flux is passed through the thin film coil 3 through the medium 34, and a magnetic path is formed between the magnetic thin film 22 and the magnetoresistive thin film 27 through the medium, whereby predetermined information is recorded on the medium.

At the time of reproduction, a predetermined current is supplied to the magnetoresistive magnetic thin film 27 from the DC power supply circuit 37, and a change in the resistance of the magnetoresistive magnetic thin film 27 is input as a reproduction signal to the reproduction signal input circuit 38 by a magnetic field from the medium. Is done.

Therefore, in the thin-film magnetic head of this embodiment and the recording / reproducing apparatus using the same, the magneto-resistance effect thin film is formed on the medium contact surface of at least one of the magnetic thin films constituting the thin-film magnetic head by a magnetic material having a magneto-resistance effect. It is formed to act as a magnetic pole when recording information, and thin film conductors for supplying detection current are formed at both poles of this magnetoresistive effect thin film. it can. An output section outputs a signal current corresponding to information to be recorded on the thin-film coil at the time of recording, and outputs a bias current to the thin-film coil at the time of reproduction, and a reproduction signal which is a change in electric resistance of the magnetoresistive thin film at the time of reproduction. It has an input section for input from conductors, so it is used as a thin-film magnetic head during recording and used as a magneto-resistive head during reproduction, and a bias current is output to the thin-film coil during this reproduction. Can be improved.

FIG. 4 is a view showing a thin-film magnetic head according to another embodiment of the present invention, and the same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals, and redundant description will be omitted.

As shown in the figure, in this embodiment, the ferromagnetic thin film portions 41 and 4 such as CoP are provided on both sides of the magnetoresistive magnetic thin film 27.
2 are formed. Thus, the magnetoresistive magnetic thin film 27 is a single magnetic domain in the direction of the arrow A in the track width direction.

Therefore, in this embodiment, noise during reproduction can be reduced.

In the above-described embodiment, the magnetoresistive effect magnetic thin film is formed on a part of the magnetic thin film constituting the magnetic core on the side of the medium contact portion. However, the entire magnetic thin film may be a magnetoresistive effect magnetic thin film. A magnetoresistive magnetic thin film may be formed on one side and both sides of the gap.

[Effects of the Invention] As described above, the thin-film magnetic head and the recording / reproducing apparatus of the present invention can be reduced in size with a simple configuration, and the recording efficiency and the reproducing efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a thin film magnetic head according to one embodiment of the present invention, FIG. 2 is a plan view showing a part of FIG.
FIG. 4 is a plan view showing a recording / reproducing apparatus of one embodiment of the present invention using the thin-film magnetic head of FIG. 1, FIG. 4 is a plan view showing a thin-film magnetic head of another embodiment of the present invention, and FIG. FIG. 6 is a partial cross-sectional perspective view showing an example of a conventional thin-film magnetic head, FIG. 6 is a perspective view showing a conventional magnetoresistive head, and FIG.
FIG. 4 is a diagram for explaining a change in resistance of the head shown in FIG. 22 first magnetic thin film, 23 thin film coil, 24 insulating film, 25 nonmagnetic thin film, 26 second magnetic thin film, 27
Magnetoresistive effect magnetic thin film, 28, 29 ... terminal, 30, 31 ... lead wire, 32 ... protective film, 33 ... medium contact surface, 34 ... switching circuit, 35 ... recording signal output circuit, 36 ... ... bias current output circuit, 37 ... DC power supply circuit, 38 ... reproduction signal input circuit, 41, 42 ... ferromagnetic thin film section.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Tetsuo Inoue 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Inside the Home Appliance Research Laboratory, Toshiba Yokohama Office (56) References JP-A-62-3414 (JP, A) 63-96713 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G11B 5/39 G11B 5/31

Claims (3)

(57) [Claims] 1. A non-magnetic thin film is formed on a part of a first magnetic thin film, and a ring-shaped thin-film coil is formed insulated by an insulating film, and is formed on the non-magnetic thin film and on the insulating film. A second magnetic thin film is formed, a protective film is formed on the second magnetic thin film, and a medium is brought into contact with a surface where the end surfaces of the first and second magnetic thin films and the nonmagnetic thin film are exposed. In a thin film magnetic head having a surface formed thereon, a magnetoresistive thin film is formed on at least one of the magnetic thin films on the medium contact surface by a magnetic material having a magnetoresistive effect so as to act as a magnetic pole when information is recorded. ,
A thin-film magnetic head, wherein thin-film conductors for supplying a detection current are formed at both pole ends of the magnetoresistive effect thin film. 2. The thin film magnetic head according to claim 1, wherein
A thin-film magnetic head, wherein a ferromagnetic thin film is formed on both pole ends of the magnetoresistive effect thin film, and the magnetoresistive effect thin film is a single magnetic domain. 3. A recording / reproducing apparatus using the thin-film magnetic head according to claim 1, wherein a signal current corresponding to information to be recorded on the thin-film coil is output during recording, and the signal current is supplied to the thin-film coil during reproduction. A recording / reproducing apparatus comprising: an output unit for outputting a bias current; and an input unit for inputting a reproduction signal, which is a change in electric resistance of the magnetoresistive thin film during reproduction, from the thin film conductor.