JPH07230608A - Magnetic head - Google Patents

Abstract

PURPOSE:To attain the ultra-high density of magnetic recording by providing a part of a second magnetic path with a magnetic flux modulating part to be impressed with the magnetic fields from a magnetic recording medium. CONSTITUTION:This magnetic head has the first magnetic path 4 to be infiltrated with the magnetic fluxes occurring in the magnetic moment of the magnetic recording medium from magnetic poles 4a, 4b, the second magnetic path 5 intersecting with the magnetic path 4 and a high-frequency magnetic flux impressing means 7 for impressing the high-frequency magnetic fluxes higher than the signal frequency by recording information of the magnetic recording medium to the magnetic path 5. Further, the magnetic head as an amplitude detecting means 8 for detecting the amplitude of the high-frequency magnetic flux in the second magnetic path 5 as well. The propagation from the high-frequency magnetic flux impressing means 7 side of the high-frequency magnetic flux in a frequency region exceeding the signal frequency from the magnetic recording medium to the amplitude detecting means 8 side is controlled by the magnetic field from the first magnetic path 4 occurring in the magnetic moment of the magnetic recording medium to be impressed to the magnetic flux modulating section 6. The magnetic head for reproduction which is capable of detecting the slight magnetic moment of the magnetic recording medium and has a high sensitivity is, therefore, provided and the ultra-high density of magnetic recording is attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head suitable for reproducing an ultra high density magnetic recording medium.

[0002]

2. Description of the Related Art Conventionally, as a reproducing magnetic head for reading information recorded on a magnetic recording medium, an inductive head, an MR head utilizing a magnetoresistive effect and the like are known. The inductive head can be usually used also as a recording head, and a thin film head having a low inductance has been used as a head for a magnetic disk or the like in response to high density and high frequency of magnetic recording. It is a thing. Since the reproduction output of such an inductive head depends on the relative speed of the magnetic head and the recording medium, it is somewhat difficult to cope with a small disk having a relatively low reproduction frequency.

Therefore, in order to cope with the miniaturization and the ultra-high density of the magnetic disk, an MR head whose reproduction output does not depend on the relative speed with the recording medium is proposed by Japanese Patent Laid-Open No. 5-196714. Is. Further, as a magnetic sensor, a sensor that utilizes a change in magnetic permeability of a magnetic core is also known. However, these magnetic heads cannot be applied to the reproduction of an ultra high density magnetic recording medium which needs to detect a minute magnetic moment.

Further, a new type of magnetic head using microwaves has also been proposed in Japanese Patent Laid-Open No. 5-234170. This utilizes the fact that the state of the standing wave or the traveling wave of the microwave in the microwave waveguide changes due to the change in the magnetic permeability of the ferromagnetic film.

[0005]

However, in the case of the microwave waveguide type magnetic head, in order to obtain a sufficient reproduction output, the magnetic permeability of the region of the microwave wavelength or more is determined by the magnetic moment of the magnetic recording medium. Need to change. Therefore, the magnetic moment of the magnetic recording medium needs to have a certain magnitude, and there is a limit to how to deal with an ultra-high density magnetic recording medium that needs to detect a minute magnetic moment. Further, in order to increase the reproduction output, when the microwave intensity is increased, the magnetic pole near the magnetic recording medium is magnetized by the microwave magnetic field, and the magnetization recorded in the magnetic recording medium is liable to be impaired. There is a problem that an electric field is generated, which easily adversely affects other electronic circuits.

After all, in order to realize an ultrahigh density magnetic recording system exceeding several Mbit / mm ² , it is necessary to develop a new magnetic head for reproduction with high sensitivity capable of detecting a minute magnetic moment of the medium. is there.

[0007]

According to another aspect of the present invention, there is provided a first magnetic path through which a magnetic flux resulting from a magnetic moment of a magnetic recording medium enters from a magnetic pole, and a second magnetic path intersecting the first magnetic path. And a magnetic flux modulator formed in a part of the second magnetic path to which the magnetic flux from the first magnetic path is applied, and a signal frequency higher than the signal frequency according to the recording information of the magnetic recording medium in the second magnetic path. A magnetic head is constituted by a high frequency magnetic flux applying means for applying a high frequency magnetic flux and an amplitude detecting means for detecting the amplitude of the high frequency magnetic flux in the second magnetic path.

According to a second aspect of the present invention, with respect to the configuration of the first aspect of the invention, a magnetic head compatible with a digital magnetic recording medium, wherein the frequency of the high frequency magnetic flux applied to the high frequency magnetic flux applying means is set to The reproduction frequency of the recorded information was n times (n is a natural number of 2 or more).

According to a third aspect of the invention, in the configuration of the first aspect of the invention, the magnetic field from the first magnetic path and the magnetic field from the second magnetic path are made orthogonal to each other in the magnetic flux modulating section.

According to a fourth aspect of the invention, in the configuration of the third aspect of the invention, a third magnetic path for applying a magnetic field for changing the high frequency magnetic field in the magnetic flux modulating section to a rotating magnetic field is added.

According to a fifth aspect of the invention, in the configuration of the first aspect of the invention, the easy axis of magnetization of the magnetic body forming the magnetic flux modulating portion is set parallel to the magnetic field direction from the second magnetic path.

According to a sixth aspect of the present invention, in the configuration of the first aspect of the invention, the magnetic permeability of the magnetic body forming the second magnetic path of the magnetic flux modulating section in the frequency range in which the high frequency magnetic flux is applied is set to It was set to be lower than the magnetic permeability of the magnetic body forming the region other than the magnetic flux modulation section in the two magnetic paths.

According to a seventh aspect of the invention, in the configuration of the sixth aspect of the invention, the magnetic permeability of the magnetic body forming the first magnetic path in the frequency region where the high frequency magnetic flux is applied is determined by the magnetic flux in the second magnetic path. It was set lower than the magnetic permeability of the magnetic material forming the region other than the modulation portion.

According to an eighth aspect of the present invention, in the configuration of the first aspect of the invention, the magnetic path length from the magnetic pole of the first magnetic path to the magnetic flux modulating section is determined by the high frequency magnetic flux applying means of the second magnetic path and the amplitude detection. It was set longer than the magnetic path length between the means.

According to a ninth aspect of the invention, in the structure of the first aspect of the invention, the high frequency magnetic flux applying means is shielded with a metal.

[0016]

The high frequency magnetic flux applying means generates a high frequency magnetic flux in the second magnetic path. This magnetic flux propagates to the amplitude detecting means side with an intensity according to the magnetic permeability of the second magnetic path. For this reason,
The high frequency magnetic flux reaches the amplitude detecting means. Where the second
If the magnetic permeability of the magnetic path changes, the amplitude of the high frequency magnetic flux in the amplitude detecting means changes. This change in amplitude is due to the leakage of the magnetic flux to the surroundings and to the loss such as leakage loss. By changing the magnetic permeability of the second magnetic path in the high frequency region, the amplitude of the high frequency magnetic flux induced in the amplitude detecting means can be changed. According to the first aspect of the present invention, since the magnetic flux modulating section to which the magnetic field from the magnetic recording medium is applied is present in a part of the second magnetic path, the magnetic flux from the magnetic recording medium passes through the magnetic pole and then passes through the magnetic pole. A magnetic field corresponding to the magnetic flux from the magnetic recording medium is applied to one magnetic path and applied to a part of the second magnetic path in the magnetic flux modulating section, and the high frequency magnetic flux of the magnetic flux modulating section is modulated. Thus, in the magnetic flux modulator, the second
When the high frequency magnetic permeability of the magnetic path is changed according to the change of the magnetic field from the magnetic recording medium, the magnetic flux of the amplitude detecting means is modulated according to the magnetic moment of the magnetic recording medium. That is, the magnetic flux modulator exists between the high frequency magnetic flux applying means and the amplitude detecting means, and the propagation of the high frequency magnetic flux to the amplitude detecting means is controlled by the magnetic flux from the first magnetic path caused by the magnetic moment of the magnetic recording medium. Therefore, the amplitude of the magnetic flux transmitted to the amplitude detecting means depends on the change in the magnetization of the magnetic recording medium. Therefore, the magnetic field of the magnetic recording medium can be detected. In this case, the high frequency magnetic flux by the high frequency magnetic flux applying means has a frequency higher than the signal frequency of the magnetic recording medium, and as the frequency increases, it becomes possible to obtain a larger detection output with a smaller high frequency magnetic flux amplitude. Therefore, in general, the larger the ratio of the frequency of the high frequency magnetic flux supplied to the high frequency magnetic flux applying means to the signal frequency of the magnetic recording medium in the frequency range below the frequency where the ferromagnetic resonance is recognized, the higher the ratio to the conventional inductive head. And good reproduction characteristics can be obtained. Furthermore, it is possible to reproduce at a low frequency that cannot be read by the conventional inductive head.

In the digital magnetic recording, when the reading frequency is high and the ratio of the frequency of the high frequency magnetic flux and the signal frequency of the magnetic recording medium is close to each other, the frequency of the high frequency magnetic flux is magnetically recorded. Since the reproduction frequency of the medium is matched with a natural number multiple of n times or more, which is n times, the reproduction can be performed in a state with a good S / N ratio.

By the way, a part of the high frequency magnetic flux existing in the magnetic flux modulating portion of the second magnetic path enters the first magnetic path and a part of the high frequency magnetic flux reaches the magnetic pole. The high frequency magnetic field at the magnetic pole must be in a range that does not change the magnetization state of the magnetic recording medium. Therefore, it is preferable that the magnetic permeability in the high frequency region of the first magnetic path is small and the attenuation is large. On the other hand, in the frequency region of the magnetic recording signal, it is required that the magnetic recording medium has a large magnetic permeability enough to transmit the magnetic signal of the magnetic recording medium to the magnetic flux modulating section. For this purpose, the magnetic permeability of the first magnetic path in the frequency region where the high frequency magnetic flux is applied may be set lower than the magnetic permeability of the second magnetic path. Further, as in the invention described in claim 8, the magnetic path length from the magnetic pole of the first magnetic path to the magnetic flux modulating section is determined from the magnetic path length between the high frequency magnetic flux applying means and the amplitude detecting means of the second magnetic path. It should be long.

In the frequency range of the magnetic signal from the magnetic recording medium, it is desirable that the magnetic permeability of the first magnetic path is large and the attenuation is small. In this respect, as in the invention described in claim 6, the magnetic permeability of the magnetic path coupling portion, that is, the magnetic flux modulation portion in the frequency region in which the high frequency magnetic flux is applied is set to If it is lower than the magnetic susceptibility, the amount of the leakage magnetic flux due to the decrease in the magnetic permeability due to the magnetic field from the first magnetic path increases, so that the magnetic head has high sensitivity.

In this way, by detecting the amplitude change of the high frequency magnetic flux, the change of the magnetic flux from the magnetic recording medium can be detected. Since the frequency of the high frequency magnetic flux is higher than the frequency of the magnetic signal of the magnetic recording medium, a large signal output can be obtained with a weak high frequency magnetic field amplitude. At the same time, since this output does not depend so much on the temporal change of the magnetic flux from the magnetic recording medium, a sufficiently large output can be obtained even at a low reading frequency.

Further, normally, in order to improve the initial magnetic permeability of the magnetic body forming the magnetic path, the magnetic path may be set parallel to the hard axis. In the invention according to claim 5, The easy axis of magnetization of the magnetic body forming the magnetic flux modulation section is set to the second
It is set parallel to the magnetic field direction from the magnetic path. In this case,
If the magnetic field due to the first magnetic path has sufficient strength to exceed the anisotropic magnetic field of the magnetic substance of the magnetic flux modulating section, the magnetic domain structure of the magnetic flux modulating section is such that the easy axis is parallel to the first magnetic path. Can be similar to. This makes it possible to increase the change in the magnetic permeability of the magnetic flux modulator, and to favorably control the propagation of the high frequency magnetic flux by the magnetic field from the first magnetic path. In particular, as in the invention described in claim 3, it becomes remarkable in the case of the structure in which the first magnetic path and the second magnetic path are orthogonal to each other by the magnetic flux modulator.

Further, in the invention having the high frequency magnetic flux applying means as in the third aspect of the invention, if the third magnetic path is added and the first and second magnetic paths are made orthogonal to each other, the magnetic field of the magnetic flux modulating section is increased. It is possible to apply a two-dimensional high-frequency magnetic field to the body, and in particular, it is also possible to apply a rotating magnetic field orthogonal to the external magnetic field from the magnetic recording medium in the frequency region where ferromagnetic resonance is recognized.

If the high frequency magnetic flux applying means is shielded with a metal as in the ninth aspect of the invention, noise to other circuits can be reduced.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. The magnetic head 1 of this embodiment is configured as, for example, a thin film magnetic head for an in-plane magnetic recording medium (not shown), and is basically formed on the substrate 2 by a thin film forming process. First, as shown in FIG. 1, a first magnetic path 4 having a pair of magnetic poles 4a and 4b via a gap 3 is formed so as to form a substantially U-shaped open magnetic path in a vertical plane. Further, a second magnetic path 5 having an intersecting portion with such a first magnetic path 4 and forming a closed magnetic path in a horizontal plane is formed. The intersection of the first and second magnetic paths 4 and 5 is a single (or a plurality of) magnetic flux modulator 6. In addition, the magnetic flux modulator 6 is located on both sides of the second magnetic path 5,
A high frequency magnetic flux applying means 7 and an amplitude detecting means 8 are provided. The high-frequency magnetic flux applying means 7 comprises, for example, a high-frequency electric field applying coil 9 and a high-frequency power source 10 which are wound around the second magnetic path 5, and the amplitude detecting means 8 is wound around the second magnetic path 5, for example. The detection coil 11 and the induction high frequency electric field measuring means 12 are formed in a rotating state. FIG. 2 is a conceptual diagram showing an equivalent magnetic circuit formed by the magnetic head 1 including such components.

Here, as the material of the first magnetic path 4,
Magnetic materials such as permalloy, sendust, iron, iron nitride, and ferrite can be used alone or in combination, and in particular, they have a high saturation magnetic flux density and can be transmitted in the range of several 100 kHz to several 10 MHz which is the frequency band of magnetic signals. A metal-based magnetic material having a high magnetic susceptibility and a large loss in a high frequency region exceeding the magnetic susceptibility is preferable, and sendust is used in the present embodiment.

However, the first magnetic path 4 may be formed as a magnetic path having a structure similar to that of a ring type head or a single magnetic pole head used in a conventional magnetic head, other than the structure of this embodiment. That is, the first magnetic path 4 has a magnetic pole, and as the magnetic pole structure, as shown in the figure, a pair of magnetic poles 4a and 4b are opposed to each other through the gap 3 and a known magnetic pole structure such as a single magnetic pole structure. A magnetic pole similar to the magnetic pole of the magnetic head used for recording can be used, and is designed according to the characteristics of the target magnetic recording medium. Further, a head structure in which one or more additional coils are arranged near the magnetic poles and a magnetic field for canceling the high frequency magnetic flux near the magnetic poles is applied is also possible. In this case, the additional coil can be used for writing magnetic information on the magnetic recording medium. However, the magnetic flux modulator 6 corresponding to the back gap
In order to obtain a sufficient magnetic flux density, it is important to make the cross-sectional area of the neighboring first magnetic path 5 sufficiently small as shown in FIG. 1 (a).

The voids such as the gap 3 are filled with a filler 13 made of SiO ₂ thin film, glass, resin or the like, and the surface layer of the first magnetic path 4, the filler 13 or the like is filled with a protective layer 14 such as alumina. To be covered.

On the other hand, with respect to the second magnetic path 5, the magnetic material forming the portion other than the magnetic flux modulating portion 6 may be the same as the magnetic material of the first magnetic path 4, but has a high magnetic permeability in the high frequency region. It is desirable to have For example, a metal magnetic material or the like in which eddy current loss is suppressed by combining a ferrite and an insulating layer is preferable. In this embodiment, iron nitride forming a multilayer structure with an insulating layer is used. In order to obtain a predetermined magnetic permeability, these magnetic bodies are subjected to known treatments such as heat treatment and rotating magnetic field treatment so that the anisotropic magnetic field has a predetermined value. Such a second magnetic path 5 may be a closed magnetic path structure as in the present embodiment, an open magnetic path structure as described later, or a structure having a narrow gap near the magnetic flux modulation section 6 or the like. .

Further, it is desirable that the magnetic permeability of the magnetic material forming the magnetic flux modulating portion 6 in the second magnetic path 5 greatly changes according to the magnetic field from the first magnetic path 4. In this respect, in a general magnetic material, the magnetic permeability with respect to a high frequency magnetic field changes due to the presence of an external magnetic field such as a direct current magnetic field or an alternating current magnetic field having a longer period than the high frequency magnetic field. Then, as a principle of obtaining a large change in magnetic permeability of the magnetic flux modulating section 6, the magnetic flux from the first magnetic path 4 is realized by saturating the magnetic body of the magnetic flux modulating section 6 forming the magnetic coupling section, and Even when the modulator 6 is unsaturated, the magnetic field wall structure is changed by the external magnetic field applied to the magnetic flux modulator 6 by the first magnetic path 4 to change the magnetic permeability, and the magnetic resonance is caused by the external magnetic field caused by the magnetic recording medium. The magnetic flux modulation unit 6 at a constant frequency by changing the frequency
The magnetic permeability of the magnetic recording medium is changed by an external magnetic field caused by the magnetic recording medium. Therefore, as the magnetic material forming the magnetic flux modulating portion 6 in the second magnetic path 5, metal, ferrite, or the like is selected according to the characteristics, and a known manufacturing method and treatment are selected so that predetermined magnetic characteristics can be obtained. .

For example, when saturating the magnetic flux modulator 6, a magnetic substance having a low saturation magnetic flux density is used as the magnetic substance of the magnetic flux modulator 6. Further, in the case of changing the domain wall structure of the magnetic body of the magnetic flux modulation section 6 by the magnetic field from the first magnetic path 4, the geometrical shape such that the magnetic field by the first magnetic path 4 and the easy axis of magnetization are not parallel to each other. Arrangement is desirable. In these cases, it is desirable that the first and second magnetic paths 4 and 5 are orthogonalized by the magnetic flux modulator 6 as shown in the drawing. In particular, when utilizing the ferromagnetic resonance due to the magnetic field applied by the first magnetic path 4, a geometrical arrangement in which the magnetic field by the first magnetic path 4 and the magnetic field by the second magnetic path 5 are orthogonal to each other is important. . Further, a high-frequency magnetic field applied by an additional third magnetic path (not shown) orthogonal to the first and second magnetic paths 4 and 5 is added, and the high-frequency wave of the magnetic flux modulator 6 forming the magnetic coupling portion is added. It is preferable to adjust the amplitude and phase of the magnetic flux in the third magnetic path by adjusting the high frequency magnetic flux applying means attached to the third magnetic path so that the magnetic field becomes a rotating magnetic field.

In this embodiment, the magnetic substance of the magnetic flux modulator 6 is permalloy. The magnetic flux of the magnetic flux modulator 6 due to the first magnetic path 4 due to the magnetic moment of the magnetic recording medium is generated by the substrate 2
It is almost perpendicular to the surface, and the high frequency magnetic flux of the magnetic flux modulator 6 is substantially parallel to the surface of the substrate 2. The second and first magnetic paths 5 and 4 are continuous and share the magnetic flux modulator 6. The structure is such that the cross-sectional area of the first magnetic path 4 gradually decreases as it approaches the magnetic flux modulator 6.

However, the structure of the magnetic flux modulator 6 is not limited to the illustrated example. For example, the second magnetic path 5 may be continuous, and may be connected to the first magnetic path 4 via a thin nonmagnetic layer on the side wall of the magnetic flux modulator 6 of the second magnetic path 5. Also, the second
A thin non-magnetic layer may be formed at the boundary of the magnetic flux modulation section 6 of the magnetic path 5 so as to be connected to the first magnetic path 4. In short, the structure of the magnetic flux modulator 6 may be any structure that allows the magnetic field applied to the first magnetic path 4 to affect the magnetic permeability of the second magnetic path 5.

The high-frequency magnetic flux applying means 7 may be, for example, a waveguide type one as well as the one having the coil 9 connected to the high-frequency power source 10 as shown in this embodiment. Further, the amplitude detecting means 8 detects the magnetic flux of a certain portion of the second magnetic path 5 or the temporal change thereof, and the temporal change of the magnetic flux in the second magnetic path 5 as shown in this embodiment. In addition to the one using the coil 11 that generates an electromotive force according to the above, for example, one using a high frequency compatible magnetoresistive element or the like may be used. As a structure of these coils, a known inductor or the like such as a spiral coil type or another structure can be used. In any case, in the case of the high frequency magnetic flux applying means 7 or the amplitude detecting means 8 using a coil, the length between the terminals of the conductive member of the coil 9 or 11 is set to be about 1/8 or less of the wavelength of the high frequency magnetic flux and is fine. If so, the inductance becomes extremely small, and it becomes suitable for high frequency driving. Further, the phase difference between the electric field and the magnetic field in the coil can be neglected, and unlike the case of the microwave waveguide which causes the phase difference problem, it can be handled like an inductor at a low frequency. Further, if the magnetic path length of the second magnetic path 5 is sufficiently short, the phase difference of the high-frequency magnetic flux in the second magnetic path 5 can be arbitrarily reduced as well. Different from the usual microwave waveguide.

The frequency of the high frequency power source 10 in the high frequency magnetic flux applying means 7 is adjusted according to the material used for the first and second magnetic paths 4, 5 and the magnetic flux modulating section 6 and the state thereof. In particular, a frequency is selected so that the magnetic permeability of the first magnetic path 4 is sufficiently low. This means that the high frequency magnetic flux generated by the high frequency magnetic flux applying means 7 does not reach the magnetic recording medium so much, so that the high frequency magnetic field applied to the magnetic recording medium can be made extremely low. Therefore, the magnetic information recorded on the magnetic recording medium is not damaged. On the other hand, the frequency of the magnetic field given by the magnetic recording medium, that is,
From 0 kHz to several tens of MHz, it is desirable that the first magnetic path 4 has a sufficiently large magnetic permeability and a small loss. It is desirable that the magnetic substance of the magnetic flux modulator 6 has a large dependency of the magnetic permeability on the external magnetic field in the vicinity of the frequency of the high frequency magnetic flux. In consideration of such a point, in the present embodiment, the materials of the magnetic bodies forming the first and second magnetic paths 4 and 5 are made different from each other.

However, in addition to the configuration of this embodiment, for example,
The magnetic substance near the magnetic flux modulator 6 may be ferrite, and the magnetic substances in other parts may be permalloy. Generally, in a strong magnetic material, the frequency of ferromagnetic resonance is determined by the external magnetic field, the saturation magnetic flux density, the magnetic anisotropy, and the shape anisotropy of the magnetic material, which changes momentarily according to the external magnetic field. Therefore, obtaining a strong magnetic field is also important. Magnetic flux modulator 6
It is important to make the cross-sectional area of the first magnetic path 4 sufficiently small in order to sufficiently increase the magnetic field due to the magnetic moment of the magnetic recording medium in 1.

Further, in the configuration diagram of FIG. 1 and the equivalent magnetic circuit conceptual diagram of FIG. 2, the first and second magnetic paths 4 and 5 are orthogonal to each other in the magnetic flux modulating section 6, but other The magnetic flux modulator 6 having the structure and the second magnetic path 5 may be configured. For example, as shown in an equivalent magnetic circuit conceptual diagram of FIG.
May be formed as an open magnetic path, and the magnetic field from the first magnetic path 4 and the magnetic field from the second magnetic path may be formed parallel to each other in the magnetic flux modulator 6.

[0037]

According to the first aspect of the invention, the first magnetic path through which the magnetic flux resulting from the magnetic moment of the magnetic recording medium enters from the magnetic pole, and the second magnetic path intersecting with the first magnetic path, A magnetic flux modulator formed in a part of the second magnetic path to which the magnetic flux from the first magnetic path is applied, and a high-frequency magnetic flux higher than the signal frequency of the recorded information of the magnetic recording medium in the second magnetic path. Since the magnetic head is composed of the high frequency magnetic flux applying means for applying the magnetic field and the amplitude detecting means for detecting the amplitude of the high frequency magnetic flux in the second magnetic path, the high frequency magnetic flux in the frequency region exceeding the signal frequency from the magnetic recording medium. Since the propagation from the side of the high frequency magnetic flux applying means to the side of the amplitude detecting means can be controlled by the magnetic field from the first magnetic path resulting from the magnetic moment of the magnetic recording medium applied to the magnetic flux modulating section, a small magnetic field of the magnetic recording medium is generated. Momen Can provide a detectable sensitive magnetic head for reproduction, it is possible to enable very high density of magnetic recording.

According to the second aspect of the present invention, in the configuration of the first aspect of the invention, the frequency of the high frequency magnetic flux applied to the high frequency magnetic flux applying means is n times (n) times the reproduction frequency of the recorded information on the magnetic recording medium. Is a natural number of 2 or more). Therefore, in a magnetic head compatible with a digital magnetic recording medium, S / N
Reproduction with a good ratio is possible.

According to the invention of claim 3, in the structure of the invention of claim 1, the magnetic field from the first magnetic path and the magnetic field from the second magnetic path are made orthogonal to each other in the magnetic flux modulating section.
By making the change of the magnetic permeability of the magnetic flux modulating section large, the propagation of the high frequency magnetic flux can be well controlled by the magnetic field from the first magnetic path, and the effect of the invention according to claim 1 can be remarkably exhibited. Become.

According to the invention of claim 4, in the structure of the invention of claim 3, a third magnetic path for applying a magnetic field for making the high frequency magnetic field in the magnetic flux modulating section a rotating magnetic field is added. A two-dimensional high-frequency magnetic field can be applied to the magnetic body of the magnetic flux modulation section, and the effect of the invention according to claim 1 can be more effectively exhibited.

According to the invention of claim 5, in the structure of the invention of claim 1, the easy axis of magnetization of the magnetic body forming the magnetic flux modulating portion is set parallel to the magnetic field direction from the second magnetic path. Therefore, the change of the magnetic permeability of the magnetic flux modulation section is made large, and the propagation of the high frequency magnetic flux can be controlled well by the magnetic field from the first magnetic path, and the effect of the invention according to claim 1 is more effectively exerted. Can be done.

According to a sixth aspect of the present invention, in the configuration of the first aspect of the invention, the magnetic permeability of the magnetic body forming the second magnetic path of the magnetic flux modulating section in the frequency range in which the high frequency magnetic flux is applied is: Since it is set to be lower than the magnetic permeability of the magnetic body forming the region other than the magnetic flux modulation portion in the second magnetic path, the amount of leakage magnetic flux due to the decrease in magnetic permeability due to the magnetic field from the first magnetic path can be increased. The magnetic head can have higher sensitivity.

According to the invention of claim 7, in the structure of the invention of claim 6, the magnetic permeability of the magnetic body forming the first magnetic path in the frequency range in which the high frequency magnetic flux is applied is set to the second magnetic path. Is set lower than the magnetic permeability of the magnetic body forming the region other than the magnetic flux modulating portion, and according to the invention of claim 8, in the configuration of the invention of claim 1, from the magnetic pole of the first magnetic path. Since the magnetic path length to the magnetic flux modulator is set to be longer than the magnetic path length between the high frequency magnetic flux applying means and the amplitude detecting means of the second magnetic path, the high frequency magnetic field at the magnetic pole changes to the magnetized state of the magnetic recording medium. The invention of claim 1 which can satisfy the requirement of not giving a change and the requirement of sufficiently high magnetic permeability for transmitting the magnetic signal of the magnetic recording medium to the magnetic flux modulating section in the frequency region of the magnetic recording signal. Can be more effective It becomes as.

According to the invention of claim 9, in the structure of the invention of claim 1, since the high frequency magnetic flux applying means is shielded by a metal, noise to other circuits can be reduced. The effects of the described invention can be exhibited more effectively.

[Brief description of drawings]

FIG. 1 shows a magnetic head structure according to an embodiment of the present invention,
(A) is a schematic sectional drawing and (b) is a schematic plan view.

FIG. 2 is a conceptual diagram showing an equivalent magnetic circuit.

FIG. 3 is a conceptual diagram showing an equivalent magnetic circuit of a modified example.

[Explanation of symbols]

 4 first magnetic path 4a, 4b magnetic pole 5 second magnetic path 6 magnetic flux modulator 7 high frequency magnetic flux applying means 8 amplitude detecting means

Claims (9)

[Claims] 1. A first magnetic path in which a magnetic flux resulting from a magnetic moment of a magnetic recording medium enters from a magnetic pole, a second magnetic path intersecting with the first magnetic path, and a part of the second magnetic path. And a high frequency magnetic flux applying means for applying a high frequency magnetic flux higher than the signal frequency according to the recorded information of the magnetic recording medium to the second magnetic path, A magnetic head comprising: an amplitude detecting means for detecting the amplitude of the high frequency magnetic flux in the second magnetic path. 2. A magnetic head compatible with a digital magnetic recording medium, wherein the frequency of the high frequency magnetic flux applied to the high frequency magnetic flux applying means is n times the reproduction frequency of the recorded information on the magnetic recording medium (n is a natural number of 2 or more). The magnetic head according to claim 1, wherein 3. The magnetic head according to claim 1, wherein the magnetic field from the first magnetic path and the magnetic field from the second magnetic path are orthogonal to each other in the magnetic flux modulating section. 4. The magnetic head according to claim 3, further comprising a third magnetic path for applying a magnetic field for changing the high frequency magnetic field in the magnetic flux modulator to a rotating magnetic field. 5. The magnetic head according to claim 1, wherein the easy axis of magnetization of the magnetic material forming the magnetic flux modulating portion is set parallel to the magnetic field direction from the second magnetic path. 6. The permeability of the magnetic body forming the second magnetic path of the magnetic flux modulating section in the frequency range in which the high frequency magnetic flux is applied is set to the magnetic body forming the area other than the magnetic flux modulating section in the second magnetic path. The magnetic head according to claim 1, wherein the magnetic permeability is set to be lower than the magnetic permeability. 7. The magnetic permeability of the magnetic body forming the first magnetic path in the frequency range in which the high frequency magnetic flux is applied is lower than the magnetic permeability of the magnetic body forming the area other than the magnetic flux modulating section in the second magnetic path. The magnetic head according to claim 6, wherein the magnetic head is set. 8. The magnetic path length from the magnetic pole of the first magnetic path to the magnetic flux modulating section is set longer than the magnetic path length between the high frequency magnetic flux applying means and the amplitude detecting means of the second magnetic path. The magnetic head according to claim 1. 9. The magnetic head according to claim 1, wherein the high frequency magnetic flux applying means is shielded with a metal.