JPH03171410A - Thin film magnetic head for recording and reproducing - Google Patents

Abstract

PURPOSE:To enable recording and reproduction with a high SN ratio by performing the reproduction by utilizing the magneto-resistance effect of a magnetic film while applying a bias magnetic filed by using a thin film coil and a permanent magnet film or coil for biasing. CONSTITUTION:On a substrate 1, a magnetic pole 2, a magnetic gap 3, an insulating layer 4, the thin film coil 5, and an upper magnetic pole 6 are formed in order. On its top surface, the magnetic film 8 with the magneto-resistance effect is formed across a nonmagnetic insulating layer 7 and on the magnetic film 8, the permanent magnet film (or thin film coil) 10 is formed across a nonmagnetic insulating layer 9. Then this magnetic permanent film applies a bias magnetic field to the magnetic film 8. The reproduction is performed by using this magnetic film 8 as an element which has sensitive high frequency magnetic permeability variation with a signal magnetic field from a magneto- resistance effect element or magnetic recording medium. Consequently, the high-sensitivity, high-SN-ratio signal reproduction becomes possible.

Description

[Detailed Description of the Invention] [Purpose of the Invention (Field of Industrial Application) The present invention relates to magnetic heads and is particularly suitable for improving recording density or narrowing tracks, and for recording and reproducing signals with high sensitivity and high S/N ratio. The present invention relates to a thin film magnetic head for both recording and reproducing purposes that is easy to manufacture and that enables both recording and reproduction.

(Prior art) With the recent increase in the density of magnetic recording, the number of tracks? Width is 10
There is a growing demand for the realization of thin film magnetic heads of micrometers or less. Generally, if the track width is narrow, the output will be reduced. This decrease can be compensated for by increasing the coercive force of the medium and increasing the number of turns in the coil.
In the case of conventional inductive thin-film magnetic heads, in order to increase the number of turns without reducing head efficiency, it is necessary to reduce the coil pitch compared to conventional methods. We have to deal with it by increasing it. For this reason, more delicate thin film processing technology is required.
Thin film magnetic heads become expensive. Furthermore, if the number of turns of the coil is increased, the output increases, but the impedance noise of the head also increases accordingly, so there is a limit to the increase in the number of turns due to the problem of the signal-to-noise ratio of the reproduced signal.

On the other hand, a conventional ring-shaped thin-film magnetic head is used for recording, and this magnetic core is shared or a separate magnetic core is used for reproduction. As is known as the active head principle, the method converts the sharp change in the high frequency permeability of the magnetic pole in response to the signal magnetic field from the recording medium into a voltage change to make the signal 1 highly sensitive. A reproduction method has been proposed (Japanese Patent Laid-Open No. 57-86407).
Publication No.). In these cases, sufficient recording can be achieved by increasing the current during recording without increasing the number of coil turns, and when re-seating, it is possible to detect the output corresponding to the signal magnetic field (leakage magnetic field) from the recording medium without using a coil. Therefore, the realization of a thin-film magnetic bed for both recording and reproduction, which can be easily manufactured using this method, has been awaited.

(Problem to be Solved by the Invention) As described above, the conventional induction type thin film magnetic head has the disadvantage that there is a limit to the increase in the number of coil turns, and sufficient reproduction output cannot be obtained in response to future narrower tracks. had/had.

An object of the present invention is to solve the problems of the prior art as described above, and to provide a thin film magnetic head for both recording and reproducing, which is capable of recording and reproducing signals recorded at high recording density with high sensitivity and with a high signal-to-noise ratio, and which is easy to manufacture. 6. To provide.

[Structure of the Invention] (Means for Solving the Problems) The thin film magnetic head for both recording and re-seating of the present invention first includes a lower magnetic pole on a substrate and an upper magnetic pole provided on the lower magnetic pole with a magnetic gap therebetween. A ring-shaped thin film magnetic core is formed, and a thin film coil is magnetically coupled to the thin film magnetic core.
Further, a magnetic film and a permanent magnet film or a thin film coil for bias are sequentially formed on at least one of the upper magnetic pole and the lower magnetic pole in an electrically insulated state and are made of a material exhibiting a magnetoresistive effect. In addition, in Journal J7, a recording current is supplied to a thin film coil, and during reproduction, a bias magnetic field is applied to the magnetic film using a thin film coil and a permanent magnet film or a bias coil, and the magnetoresistive effect of the magnetic film is utilized. The present invention is characterized in that playback is performed by

Second, the thin film magnetic head for both recording and reproduction of the present invention includes a ring-shaped thin film magnetic core consisting of a top magnetic pole formed on a plate and an upper magnetic pole provided through a magnetic gap between the lower magnetic pole and the lower magnetic pole; A thin film coil that is magnetically coupled to the thin film magnetic core and is supplied with a recording current during recording; a magnetic film that is electrically insulated and formed on at least one of the upper magnetic pole and the lower magnetic pole; The capantance structure that forms a resonant circuit together with the magnetic film, and the
It is characterized by comprising a thousand stages for supplying a frequency signal, and a signal detection circuit that detects a change in the high frequency output voltage of the resonant circuit in response to a change in the high frequency permeability of the magnetic film due to the signal magnetic flux from the magnetic recording medium. shall be.

Thirdly, the recording/reproducing thin film magnetic head of the present invention comprises a lower magnetic pole formed on a substrate and an upper magnetic pole provided on the lower magnetic pole with a magnetic gap therebetween, and at least one of the lower magnetic pole and the upper magnetic pole. is a ring-shaped structure in which a first magnetic film, an insulating second magnetic film, and a third magnetic film are magnetically coupled in a direction from the magnetic gap to the rear gap, substantially parallel to the screen plate. a thin film magnetic core, first and second electrode films formed on both sides of the second magnetic film, a thin film coil magnetically coupled to the thin film magnetic core and supplied with a recording current during recording, and 2 magnetic film and the first and second
an inductance element that is connected in parallel to the capacitance element formed by the electrode film and forms a resonant circuit together with the capacitance element; a means for supplying a high frequency signal to the resonant circuit; The present invention is characterized by comprising a signal detection circuit that detects a change in the high-frequency output voltage of the resonant circuit in response to a change in the high-frequency magnetic permeability of the magnetic film.

Fourthly, the recording/reproducing thin film magnetic head of the present invention includes a ring-shaped thin film magnetic core consisting of a lower magnetic pole formed on a substrate and an upper magnetic pole provided on the lower magnetic pole with a magnetic gap therebetween; A thin film coil magnetically coupled to the core and supplied with a recording current during recording, and a thin film coil 9 connected to both ends in the track width direction of the tip facing the magnetic recording medium of at least one of the lower magnetic pole and the upper magnetic pole. A film lead wire, a capacitance element that constitutes a resonant circuit together with the thin film lead wire, a means for supplying a high frequency signal to the resonant circuit, and a means for increasing the high frequency permeability of the tip of at least one magnetic pole by a signal magnetic flux from a magnetic recording medium. The present invention is characterized by comprising a signal detection circuit that detects a change in the high-frequency output voltage of the resonant circuit in response to a change.

(Function) In the present invention, since a common ring-shaped thin film magnetic core is used for both recording and re-seating, manufacturing of the head becomes easy.

In addition, a magnetic film that magnetically couples with the magnetic core is formed on at least one of the lower magnetic pole and the upper magnetic pole, or as a part of these magnetic poles, and this magnetic film is connected to the signal magnetic field from the magnetoresistive element or the magnetic recording medium. The device can be used as an element that exhibits a sharp change in high-frequency magnetic permeability due to the magnetic field, or can be reproduced by using a sharp change in high-frequency magnetic permeability due to a signal magnetic field from a magnetic recording medium at the tip of at least one of the lower magnetic pole and the upper magnetic pole. By doing so, it is possible to reproduce signals with higher sensitivity and higher signal-to-noise ratio than with conventional inductive thin film magnetic heads.

As a result, it becomes easier to respond to higher density or narrower tracks, and since the induction principle is not used for signal reproduction, the recording thin film coil is coupled to the ring-shaped thin film magnetic core to obtain a large reproduction output. There is no need to increase the number of windings in the head, making it easier to downsize the head, and greatly improving recording and resetting efficiency.

Furthermore, during playback, direct current and high frequency current are passed through the magnetic films that exhibit magnetoresistive effects or changes in high frequency magnetic permeability, respectively, but if these magnetic films and the thin film magnetic core are configured to be electrically insulated. , without sacrificing the efficiency of the head, and since direct current or high frequency current does not leak from the thin film magnetic core or the head to the magnetic recording medium, unnecessary noise is not generated.

(Embodiment) FIG. 1 is a cross-sectional view of a thin film magnetic head for recording and reproducing 11 according to a first embodiment of the present invention. A lower magnetic pole 2, a magnetic gap 3, an insulating layer 4, a thin film coil 5 of one turn or more, and an upper magnetic pole 6 are formed in this order on a substrate 1. The lower magnetic pole 2 and the upper magnetic pole 6 form a thin film magnetic core. A magnetic film 8 having a magnetoresistive effect is formed on the upper surface of a portion of the upper magnetic pole 6 that is substantially parallel to the substrate 1 with a nonmagnetic insulating layer 7 interposed therebetween. A non-magnetic insulating layer 9 is provided on the magnetic film 8.
A permanent magnet film (or thin film coil) 10 is formed through the permanent magnet film (or thin film coil) 10, and the configuration is such that a bias magnetic field can be applied to the magnetic film 8 by this permanent magnet film (or thin film coil) 10.

Signal recording on a magnetic recording medium (not shown) is performed by passing a recording current through the thin film coil 5. On the other hand, reproduction of signals recorded on the magnetic recording medium is performed by detecting the signal magnetic field using the magnetic film 8. Note that the thin film coil 5 can also be used as a bias coil 12 for applying a bias magnetic field to the magnetic film 8 not only during recording but also during reproduction.

This thin-film magnetic head for recording/reproduction has higher sensitivity than conventional single-induction type thin-film magnetic heads, and has a high signal-to-noise ratio.
IP. Therefore, it is suitable for high-density, high-signal-to-noise ratio recording and reproduction. Moreover, since the reproduction utilizes the magnetoresistive effect, which is inherently expected to be highly sensitive, there is no need to increase the number of turns of the thin film coil 5, unlike the induction type.
The number may be sufficient for signal recording. This results in
The head can be easily miniaturized and the recording/reproducing efficiency is improved. On the other hand, since the entire thin film magnetic core constituted by the lower magnetic pole 2 and the upper magnetic pole 6 is used for both recording and reproduction,
The head manufacturing process is not particularly complicated compared to conventional inductive thin film magnetic heads.

In order to obtain maximum reproduction sensitivity with the magnetic head of this embodiment, the thickness of the upper magnetic pole 6 and the magnetic film 8 at the position where they overlap and the ratio of these thicknesses are appropriately combined. 13 of the signal magnetic flux from the magnetic recording medium interlinked with ? The force can be obtained by maximizing the product of the amount of magnetization rotation by the signal magnetic flux. The formation of the nonmagnetic insulating layer 9 and the permanent magnet film (or thin film coil) 10 or the use of the thin film coil 5 for applying a bias magnetic field are as follows:
You can omit it if necessary. In addition, a non-magnetic insulating layer 7, a magnetic film 8, a non-magnetic insulating layer 9 and a permanent magnet film (
Although the thin film coil (10) is formed on the upper magnetic pole 6 in this embodiment, it may be formed on the upper surface of both the upper magnetic pole 6 and the lower magnetic pole 2, or only on the upper surface of the lower magnetic pole 2.

FIG. 2 is a sectional view showing a thin film magnetic head for both recording and reproduction according to a second embodiment of the present invention, which is a modification of the embodiment shown in FIG. 1. The difference from the embodiment shown in FIG. The magnetic film 8 is formed on the lower magnetic pole 2 via the nonmagnetic insulating layer 7, and has the same effect as the embodiment shown in FIG.

FIG. 3 is a sectional view of a thin film magnetic head for both recording and reproduction according to a third embodiment of the present invention, in which a substrate 14 is provided with a lower magnetic pole 2, a magnetic gap 3, an insulating layer 4, and a thin film coil of one turn or more. 5. The basic structure in which the upper magnetic poles are sequentially formed is the same as the embodiments shown in FIGS. 1 and 2. In this embodiment, a metallic first magnetic film]], an insulating second magnetic film 12, and a metallic third magnetic film 13 are formed in this order from the magnetic gap 3 to the rear gap. The upper magnetic pole is constructed by forming a junction such that the two overlap each other so that the magnetic resistance is sufficiently replaced by A-2. A magnetic film 8 is formed on the upper surface of an insulating magnetic film 12, and a permanent magnet film (or thin film coil) 10 is formed on the upper surface of the magnetic film 8 via a non-magnetic insulating layer 9 for applying a bias magnetic field thereto. It is formed.

In the recording/reproducing thin film magnetic head of this embodiment,
As in the first and second embodiments, by appropriately setting the film thicknesses of the magnetic film 8 and the insulating magnetic film 12 and their ratio, higher sensitivity and higher SN can be obtained than the conventional inductive thin film magnetic head. In addition to being able to reproduce signals with a high ratio, it is also possible to obtain the same effects as in the previous 15 embodiments.

FIG. 4 is a perspective view showing a thin film magnetic head for both recording and reproducing according to a fourth embodiment of the present invention, in which a magnetic film 8 having a magnetoresistive effect of -H in the embodiment of FIG. It is used as an element whose magnetic property changes sharply. Thin film lidding lines 2 (1 1, 20 2) are electrically connected to both ends of the magnetic film 8 in the track width direction.
The magnetic film 8 and the thin film lead wires 20-1 and 20-2 constitute an inductance element. This inductance element constitutes a high frequency resonant circuit together with the capacitance element 15, and a high frequency signal supply source 17 and a signal detection circuit 16 are connected to this high frequency resonant circuit.

Signal recording on the magnetic recording medium in this embodiment is performed in the same manner as in the above embodiments. On the other hand, reproduction of a signal recorded on a magnetic recording medium is achieved by a sharp change in the high-frequency permeability of the magnetic film 8 due to the signal magnetic flux flowing into the magnetic film 8, which generates a high-frequency signal from the high-frequency signal supply source 17 that excites the head. By supplying the resonant circuit 16 to the resonant circuit, the high frequency output voltage generated by the resonant circuit changes sharply, and this change is detected by the signal detection circuit 6.

According to this embodiment, not only can reproduction be achieved with higher sensitivity and higher S/N ratio than the embodiments shown in FIGS. 1 to 3, as well as compared with conventional inductive thin film magnetic heads, - The same effect as the second embodiment shown in Fig. 3 can be obtained. Note that, if necessary, a permanent magnet film or a thin film coil for bias application may be arranged and formed on the magnetic film 8 to apply a bias magnetic field thereto.

FIG. 5 is a perspective view showing a thin film magnetic head for both recording and reproduction according to a fifth embodiment of the present invention, which is a modification of the embodiment shown in FIG. It is formed on the magnetic pole 2 with a nonmagnetic insulating layer 7 interposed therebetween. The recording/reproducing thin film magnetic head of this embodiment has the same effects as the embodiment shown in FIG. Note that, if necessary, a permanent magnet film for applying a bias magnetic field to the magnetic film 8 or a thin film coil for applying a bias may be arranged and formed on the magnetic film 8 without any problem.

FIG. 6 is a perspective view showing a thin film magnetic head for both recording and reproduction according to a sixth embodiment of the present invention, which is a modification of the height embodiment not shown in FIG. On the membrane 12,
A magnetic film 8 whose high-frequency magnetic permeability changes sharply depending on the fs magnetic field is formed. This embodiment has similar effects to the embodiments of FIGS. 4 and 5.

FIG. 7 is a perspective view showing a thin film magnetic head for both recording and reproduction according to a seventh embodiment of the present invention, which is a modification of the embodiment shown in FIG. A magnetic film 8 whose high-frequency magnetic permeability changes sharply depending on the signal magnetic field is formed therebetween, and one thin film coil is further formed on the magnetic film 8 with a nonmagnetic insulating layer 18 interposed therebetween. The magnetic film 8 and one thin film coil form an inductance element, and this inductance element together with the gear passance element 15 constitutes a high frequency resonant circuit.

Other structures or embodiments shown in FIGS. 4 to 6 and 18 They are similar, and the effects are also the same as those of the length examples.

FIG. 8 is a front view showing a thin film magnetic bed for both recording and reproduction according to the eighth embodiment of the present invention, in which the substrate 1 mainly consists of the lower magnetic pole 2.
, a magnetic gap 3, an insulating layer 4, a thin film coil 5 having a thickness of 1 or more times, an upper magnetic pole, and a protective layer 22 are formed in this order.

The upper magnetic pole has a first magnetic film 6-1 made of metal, a second magnetic film 6-2 made of insulating material, and a third magnetic film made of metal substantially parallel to the substrate 1 in the direction from the magnetic gap 3 to the rear gap. Magnetic film 6-
3 and 5 are arranged in this order so as to be in contact with the surface of the substrate 1 with a substantially perpendicular surface to the surface of the substrate 1 so that good magnetic coupling can be achieved. Kame electrode films 21''1, 212 with good conductivity are formed on both surfaces of the second magnetic film 6-2 in the direction perpendicular to the cleaning plate 1, and these electrode films 2'l-1, 21-2 1 magnetic film 6
-1 and the third magnetic film 6-3 and the thin film coil 5 are formed so as not to be electrically conductive, and the second magnetic film 6-2 and these electrode films 21-1 and 21-2 form a capacitance element. There is one formed. An inductance element 22 is connected in parallel to this capacitance element to form a resonant path, and a high frequency signal supply source 17 and a signal detection path 16 are connected to the resonant circuit.

Signal recording on the magnetic recording medium is performed by passing a recording current through the thin film coil 5, as in the above embodiments. On the other hand, in order to reproduce the recorded signal, a high frequency is supplied from the high frequency signal supply source 17 to the resonant circuit, and the signal magnetic flux from the recording magnetization on the magnetic recording medium (the second magnetic H6- Signal detection path 16 detects changes in the high-frequency output voltage from the resonant circuit in response to changes in the high-frequency magnetic permeability.
This is done by detecting the waves.

in this case,. Signal reproduction■. In order to obtain high reproduction sensitivity for f, the thin film coil 5 is used as a coil for applying an appropriate bias magnetic field to the second magnetic film 6-2, if necessary. Therefore, reproduction can be performed with extremely high sensitivity and a high signal-to-noise ratio compared to conventional inductive thin film magnetic heads, making it suitable for higher density and narrower tracks. Moreover, 20? Because the induction principle is not used to reproduce the
There is no need to increase the number of windings of the thin film coil 5 for the purpose of
It is easy to downsize the head. As a result, the recording and reproducing efficiency is improved, and furthermore, since the ring-shaped magnetic core is used for both recording and reproducing, the structure is simple and manufacturing is easy.

FIG. 9 shows a recording/reproducing thin film magnetic head according to a ninth embodiment of the present invention, which is a modification of the missing embodiment shown in FIG. The film 6-2 and the third magnetic film 6-3 are connected to the second [@ in the direction from the magnetic gap 3 to the rear gap, substantially parallel to the substrate 1, with their respective parts overlapped, and these are magnetically In order to achieve good adhesion, they are constructed so that they are in contact with each other on substantially perpendicular planes, with the angle χ·1 in the fourth of JJ & 1. Other structures and effects are the same as those of the embodiment shown in FIG.

FIG. 10 shows a first embodiment of the present invention which is a modification of the embodiment shown in FIG.
Thin film 21 for recording and reproducing according to the embodiment No. 0 A first magnetic film 2-1 which is a magnetic head and forms a lower magnetic pole;
Insulating second magnetic film 2-2 and third magnetic film 2-23
are connected in this order in the direction from the magnetic gap 3 to the rear gap, substantially parallel to the substrate 1, overlapping each other, and in addition, the substrate 1 is connected so that these 4 can be magnetically well coupled.
Each is in contact with a plane that is approximately perpendicular to the plane of .

Other structures and effects are the same as those of the embodiment shown in FIG.

FIG. 11 is a perspective view showing a thin film magnetic head for recording and reproducing according to the eleventh embodiment of the present invention, in which a lower magnetic pole 2, a magnetic gear ship 3, an insulating layer 4, a thin film coil 5, The upper magnetic pole 6 is sequentially formed by a thin film process. Thin film lead wires 24-1 and 24-2 are electrically connected to both ends of the magnetic gap region of the lower magnetic pole 2 in the track width direction.
1.24-2 constitutes a high frequency resonant circuit together with the capacitance element 23.

This resonant circuit includes a high frequency signal supply source 17 and a signal 2 A signal detection circuit 16 is also connected.

Signal recording on a magnetic recording medium is performed using the above-mentioned length examples and between +, l,
This is done by passing a recording current through the uncoiled coil 5. On the other hand, signal reproduction of the recorded signal is done by picking up the signal magnetic flux from the head or the magnetic recording medium. i!
! The change in the high-frequency output electric current produced in the resonant circuit excited by the high-frequency signal supply source 17 due to the change in the high-frequency characteristics of the magnetic gap region of No. 2 is expressed as f. -i-th detection circuit] 6. High sensitivity is achieved by detecting. Since recording and playback can be performed using the same thin-film magnetic core, the head is not only easy to manufacture, but also reproduces signals with higher sensitivity and higher signal-to-noise ratio than conventional inductive thin-film magnetic heads. be able to. Note that the thin film lead wires 24 1-, 24
-2 may be connected to the magnetic gap region of the upper magnetic pole 6,
Moreover, even if it is connected to both ends of the upper magnetic pole 6 and the lower magnetic pole 2 in any one vertical position, it will not be supported at all.

FIG. 12 shows a recording/reproducing thin film magnetic head according to a twelfth length embodiment of the present invention, in which the 2 3 thin film lead wires 24-1, 24-2 are the same as in the height embodiment of FIG. The magnetic gap 3 of the lower magnetic pole 2 is connected to both ends in the track width direction of the magnetic gap 3 of the lower magnetic pole 2.
The width in the track width direction of the region is made wider than the width in the track width direction of the upper magnetic pole 6 that overlaps with the lower magnetic pole 2 in the region of the magnetic gap 3, and It has a structure in which the thin film wires 24-1 and 24-2 are electrically connected to the non-overlapping portions 25-1 and 25-2, respectively.

The rest of the structure is exactly the same as the embodiment shown in FIG.

According to this embodiment, the thin film lead wires 2 4-1 . 24-
2 can be realized more easily than in the embodiment shown in FIG. 11, and also has the advantage that magnetic stability in the region of the magnetic gap 3 of the lower magnetic pole 2 can be easily increased. be.

[Effects of the Invention] According to the present invention, it is possible to reproduce signals with higher sensitivity and higher signal-to-noise ratio than conventional inductive thin film magnetic heads24. Become.

In addition, since the induction principle is not used for reproduction, there is no need to significantly change the number of turns in the thin film coil interlinked with the ring-shaped magnetic core, making it easier to downsize the head, resulting in more efficient recording and reproduction. Moreover, since the entire magnetic core can be used for both recording and reproduction, it does not require particularly complicated manufacturing, similar to the inductive thin-film magnetic head of the Congregation Song Dynasty.

Furthermore, magnetic films made of materials with a magnetoresistive effect used for signal reproduction or materials whose high frequency permeability changes sharply depending on the signal magnetic field are formed insulated from the thin film magnetic core. DC current or high frequency current flowing through the magnetic film does not leak to the thin film magnetic core or the magnetic recording medium, and unnecessary noise is not generated.

[Brief explanation of the drawing]

1 to 12 are diagrams showing the structure of a thin film magnetic head for both recording and reproduction according to embodiments of the present invention. 1. Substrate, 2.. Bottom magnetic pole, 3. Magnetic gap, 4..
・Insulating layer, 5... Thin film coil, 6...'' Two magnetic poles, 7
...Nonmagnetic insulating layer, 8...Magnetic film, 9...Nonmagnetic insulating layer, 10...Permanent magnet film or bias thin film coil,] 1. Metallic first magnetic film, 12 . . . Insulating second magnetic film, 13 . . . Metallic magnetic film of the barrel 3, 1
5...Capacitance element, 16...Signal detection M path, 1
7...High frequency signal {jt source, 18...Nonmagnetic insulating layer, one...Thin film coil, 2 0-1. ,20
-2... Thin film lead wire, 21-1.21. -2...
Electrode film, 22... Inductance element, 24-1.21-2... Thin film lead wire, 25
-1.25-2... Lead wire connection part.

Claims (4)

[Claims] (1) A ring-shaped thin film magnetic core consisting of a substrate, a lower magnetic pole formed on the substrate, and an upper magnetic pole provided on the lower magnetic pole via a magnetic gap, and magnetically coupled to the thin film magnetic core. a magnetic film made of a material exhibiting a magnetoresistive effect and formed in an electrically insulated state on at least one of the upper magnetic pole and the lower magnetic pole;
A permanent magnet film or a bias thin film coil is provided on the magnetic film, and a recording current is supplied to the thin film coil during recording, and the thin film coil and the permanent magnet film or bias thin film are provided on the magnetic film during reproduction. A thin film magnetic head for both recording and reproduction, characterized in that reproduction is performed by utilizing the magnetoresistive effect of the magnetic film while applying a bias magnetic field using a coil. (2) A ring-shaped thin film magnetic core consisting of a substrate, a lower magnetic pole formed on the substrate, and an upper magnetic pole provided on the lower magnetic pole via a magnetic gap, and magnetically coupled to the thin film magnetic core. a thin film coil to which a recording current is supplied during recording; a magnetic film formed on at least one of the upper magnetic pole and the lower magnetic pole in an electrically insulated state;
a capacitance element that constitutes a resonant circuit together with the magnetic film; a means for supplying a high frequency signal to the resonant circuit; 1. A thin film magnetic head for both recording and reproduction, characterized in that it is equipped with a signal detection circuit for detecting changes in output voltage. (3) Consisting of a substrate, a lower magnetic pole formed on the substrate, and an upper magnetic pole provided on the lower magnetic pole via a magnetic gap, at least one of the lower magnetic pole and the upper magnetic pole,
A ring-shaped structure in which a first magnetic film, an insulating second magnetic film, and a third magnetic film are magnetically coupled to each other in a direction from the magnetic gap to the rear gap substantially parallel to the substrate. a thin film magnetic core, first and second electrode films formed on both sides of the second magnetic film, a thin film coil magnetically coupled to the thin film magnetic core and supplied with a recording current during recording; an inductance element connected in parallel to a capacitance element formed by the second magnetic film and the first and second electrode films and forming a resonant circuit together with the capacitance element; and supplying a high frequency signal to the resonant circuit. and a signal detection circuit that detects a change in the high-frequency output voltage of the resonant circuit in response to a change in high-frequency magnetic permeability of the second magnetic film caused by a signal magnetic flux from a magnetic recording medium. Thin film magnetic head for both recording and reproduction. (4) A ring-shaped thin film magnetic core consisting of a substrate, a lower magnetic pole formed on the substrate, and an upper magnetic pole provided on the lower magnetic pole via a magnetic gap, and magnetically coupled to the thin film magnetic core. a thin film coil to which a recording current is supplied during recording; a thin film lead wire connected to both ends in the track width direction of the tip of at least one of the lower magnetic pole and the upper magnetic pole facing the magnetic recording medium; a capacitance element constituting a resonant circuit together with a thin film lead wire; a means for supplying a high frequency signal to the resonant circuit; and a means for supplying a high frequency signal to the resonant circuit; 1. A thin film magnetic head for both recording and reproduction, characterized in that it is equipped with a signal detection circuit for detecting a change in the high frequency output voltage of the resonant circuit.