JPS60256908A - Thin film magnetic head - Google Patents

Abstract

PURPOSE:To reproduce a signal efficiently up to a high recording density by forming a magnetic gap oppositely in facing with a magnetic recording medium and specifying the ratio of the thickness of the permeable thin film to the length of the magnetic air gap in a couple of magnetic cores from one permeable thin film. CONSTITUTION:One side core is formed by imbedding a nonmagnetic substance 12 such as glass to a permeable substance 11. An MR element 15 comprising a permeable film 13 and a conductive film 14 is coupled magnetically to the surface of the permeable substance 11 via a nonmagnetic insulating film 16. The other end of the MR element 15 is coupled magnetically with the permeable thin film core 17 made of an amorphous magnetic film or the like via the nonmagnetic insulation film 16. The magnetic gap length GL formed by the permeable substance 11 and the permeable thin film core 17 and the thickness T of the thin film cre 17 have a relation of T/GL=0.5-2. Since the MR element is inserted in a magnetic path having magnetic air gap formed with the permeable substance 11 and the permeable thin film core 17 as both ends, the increase in the magnetic resistance of the magnetic path is less and an excellent characteristic is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a thin-film magnetic head used for reproducing high-density magnetic recording media.

Conventional structure and its problems Electromagnetic transducer, for example, magnetoresistive element
Conventionally, an IC head has been used as a q-type head using an electrically insulated MR element inserted into the magnetic path of a ring-shaped head, as shown in Figure 1. Ta. 1st
In the figure, 1 is a magnetically permeable material such as Ferray 4-, 2 is a non-magnetic material, 3 is a non-magnetic insulating material, 4 is a permeable film having a magnetoresistive effect such as permalloy, and 5 is a magnetically permeable film 4. M
The conductive thin film 7 constituting the R element 6 is a magnetically permeable material such as permalloy. Normally, the magnetic gap length GL is 0.3μ,
-7 Lux guide thickness T is preferably thicker for ring operation, but for practical purposes a value of about 1.5 μm is selected.

This head reproduces the signal magnetization recorded on the longitudinal recording medium, and a magnetic flux flows in accordance with the magnetic potential difference between both ends of the magnetic gap, which is detected by the MR element 6 as a resistance change. What determines the recording density characteristics is the magnetic gap length.

On the other hand, in order to reproduce the signal magnetization recorded on a perpendicular recording medium, which has the possibility of higher density recording than longitudinal recording, it is necessary to An auxiliary magnetic pole excitation type head consisting of a magnetically permeable material 9, a coil 10, etc. is used.

By the way, when trying to play back different recording media with the same device, for example, both in-plane and perpendicular recorded tapes, it is desirable to be able to play back different recording media with the same playback head. When a perpendicular recording medium is reproduced with a head, as shown in Figure 3, unevenness of recording density characteristics corresponding to the 7 lux guide WR occurs from a recording density lower than the concave due to the magnetic gap length, and it can only be used at low recording densities. . On the other hand, when reproducing a longitudinal recording medium using the J head shown in FIG. 2, the magnetic flux collection efficiency is poor and only a small output can be obtained, making it difficult to put it into practical use.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned conventional drawbacks, and aims to provide a thin-film magnetic head that can efficiently reproduce signal magnetization recorded on either in-plane or perpendicular recording media and at high recording densities. purpose.

Structure of the Invention In order to achieve the above object, the thin II! The magnetic helad includes a pair of magnetic cores that face the magnetic recording medium and face each other to form a magnetic gap, one of which is made of a magnetically permeable thin film, and a magnetic path that connects this pair of crazy cores. 1. The ratio of the length of the magnetic gap to the thickness of the magnetically permeable thin film is set to 0.5 to 2. :It is something.

According to this configuration, conventional! 1! The unevenness of the recording density characteristics that occurs when reproducing signal magnetization recorded on the own recording medium is eliminated from the practical range because the initial depression can be made to have almost the same wavelength as the depression caused by the magnetic gap, and it becomes flat. Characteristics are exploited. Therefore, it is possible to practically reproduce not only longitudinal recording media but also perpendicular recording media.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 4 is a cross-sectional view of a thin film magnetic head according to an embodiment of the present invention, in which 11 is a magnetically permeable material such as Mn-;ln ferrite, and the magnetically permeable material 11 is made of a non-magnetic material such as glass.
2 is embedded to form one side of the core. The MR element 15 is composed of a magnetically permeable film 13 such as permalloy that has no magnetoresistive effect and a conductive film 14 such as gold or aluminum.
A magnetically permeable material 11 is inserted through a non-magnetic insulating film 16 such as SiO2.
is formed at a position where it is magnetically coupled to the surface of the The nonmagnetic insulating film 16 is not necessarily necessary if the magnetically permeable material 11 has a high resistance such as Ni7n ferrite. The other end of the MR element 15 is magnetically coupled via a nonmagnetic insulating film 16 to a magnetically permeable thin film core 17 made of permalloy, an amorphous magnetic film, or the like. The magnetic gap GL formed by the magnetically permeable body 11 and the magnetically permeable thin film core 17 is 0.
．． The thickness T of the magnetically permeable thin film core 11 is also 0.25 μm.
It is 25μ. Furthermore, a cover made of photosensitive glass or barium titanate (not shown) is adhered via a non-magnetic insulating film such as SiO2, and thin lll! ! It becomes a magnetic head. In this embodiment, the MR element 15 is directly magnetically coupled to the groove end of the magnetically permeable body 11, but it may be coupled via the magnetically permeable film 13.
The key point is that the magnetic field is inserted through the non-magnetic insulating film 16 into the magnetic path whose ends are the magnetic gaps formed by the magnetic field.
゜The above structure is thin! B! When reproducing signal magnetization recorded on an in-plane recording medium such as metal powder or tape, the head operates as a ring-shaped head with a magnetic gap length of 0.25 μm, so even shortwave signals can be reproduced well. Reproduce.

On the other hand, FlW
When reproducing the A recording medium, the thin magnetically permeable thin film core 17 serves as the main magnetic pole, and guides magnetic flux to the MR element 15 in accordance with the direction of magnetization of the recording medium below it. A closed magnetic path is formed that returns from the core on the side of the recording medium through a magnetically permeable film such as permalloy of the recording medium. In this case, the core thickness is 0.
Since it is as thin as 25 μm, the recording density characteristic can be reproduced up to a high frequency range of 100K B P 1 or more, as shown in FIG. L1.

In the above embodiment, an example was shown in which the magnetic gap length OL and the magnetically permeable thin film core thickness T were equal. When reproducing a perpendicular recording medium, the first concavity of the recording density characteristic due to the magnetic gap is 11 to 1.
．． 27 wavelengths, depending on magnetic core thickness 11-1.3
It occurs at a wavelength of Ql. Therefore, if GL and T are made approximately equal, both depressions will occur at the same wavelength, and the flattest recording density characteristic will be obtained even when reproducing a perpendicular recording medium. The ratio is selected within the range of 0.5 to 2, taking into consideration the efficiency of the head and the characteristics of the recording medium. In other words, if G [- is made more sensitive, the output when reproducing a longitudinal recording medium increases, and ]; when it is made larger, the output when reproducing a perpendicular recording medium is increased.rl Depending on the characteristics of each recording medium. Accordingly, it is selected within a range that does not cause the second concavity.

Further, in the above embodiment, a material made of ferrite was used as the magnetic core 11 facing the magnetically permeable thin film core 11, that is, the magnetically permeable body 11;
A magnetically permeable amorphous film or the like formed on a nonmagnetic substrate may be used as long as it is sufficiently thicker than the thickness of the substrate.

Regarding the thickness of the magnetically permeable thin film core 17 and the length of the magnetic gap, perpendicular recording has better characteristics because it also reproduces the signal magnetization of perpendicular recording media, which has better characteristics up to shorter wavelengths than longitudinal recording media. It is particularly effective if the thickness is set to 0.5 μm or less.

Next, a second embodiment of the present invention will be described using FIG. 6. 18 is a high-resistance magnetic permeable material such as Ni7n FJ-lite, 19 is In'Sb'a: a Hall effect element composed of a thin film 20 and a conductive thin film lead wire 21, 22
is a non-magnetic insulating material such as 8Ω203, and 23 is a magnetically permeable film such as Sendust. The ρ of the magnetically permeable film 23 is
Although r is 0.3 μTn, F, the upper portion facing the Hall effect element 19 is 1 μm in order to reduce magnetic resistance. Further, the magnetic gap length is 0.3 μTrL.

When the Hall effect element 19 is used as an electromagnetic transducer in this case, the Hall effect element thin film is interposed perpendicular to the magnetic path, so when inserting the longitudinal direction of the thin film into the magnetic path like an MR element, Compared to 4, the increase in magnetic resistance of the magnetic path is small.
T, good characteristics can be obtained.

As described in detail, according to the present invention, it is possible to successfully reproduce both longitudinal recording media and perpendicular recording media, even those with sufficiently high density marks, without impairing their characteristics.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a conventional thin film magnetic head for reproducing in-plane recording media, Fig. 2 is a mi ili diagram of a conventional thin film magnetic head for reproducing perpendicular recording media, and Fig. An explanatory diagram of recording density characteristics when a perpendicular recording medium is reproduced by a magnetic head, FIG.
5 is an explanatory diagram of the recording density characteristics when a double recording medium is played back by the Hakuba magnetic head, and FIG. 6 is a cross-sectional view of another embodiment of the present invention. 1 is a cross-sectional view of a thin film magnetic head. DESCRIPTION OF SYMBOLS 11... Magnetically permeable body, 15... Magnetoresistive effect 51+ element, 17... Magnetically permeable film core, 18... High resistance magnetic permeable body, 19... Hall effect element, 23... Magnetically Permeable Membrane Agent Yoshihiro Morimoto Figures 1, 2, 3, Silver Density, Figure 4, 51 8, and Emphasis, Figure 6

Claims (1)

[Claims] 1. A pair of magnetic cores facing each other facing the magnetic recording medium to form a magnetic gap, one of which is made of a magnetically permeable thin film, and a magnetic path connecting the pair of magnetic cores. A thin film magnetic head comprising: an electromagnetic transducer arranged in the magnetic field, and a ratio of the length of the magnetic gap to the height of the magnetically permeable thin film is set to 0.5 to 2. 2. The thickness of the magnetically permeable thin film and the length of the magnetic gap are both 0.
．． A thin film magnetic head according to claim 1, wherein the thickness is 5 μm or less.