JPS5845620A - Thin film magnetic head - Google Patents

Abstract

PURPOSE:To reduce a patterning process, and also to constitute a titled magnetic head of a thin shape, by placing a magnetic core and a planar Hall element on the almost same plane on the substrate. CONSTITUTION:Cores 12a, 12b are constituted of a high magnetic permeability material such as permalloy, etc., and the core 12a and the core 12b are formed by patterning, on the right end of a glass substrate 11, and the left end and a projecting part 11b of the substrate 11, respectively. A lower part 12a' of the core 12a, a lower part 12b' of the core 12b, and each lower end face of the substrate 11 are formed so as to be the same plane, and are set as a tape sliding surface 13. The core 12a' and the core 12b' are formed by shifting them in the running direction A of a tape 4 by the same distance as height (h) of the projecting part 11b. A planar Hall element 4 is formed by means of vapor-deposition, around the center on the substrate 11, and is connected to the cores 12a, 12b electrically and magnetically. Hall electrodes 15a, 15b are formed by vapor-deposition, on a flat part 11a of the substrate 11. A magnetic path of the head is formed by a magnetic material of the tape 4- the core 12- the planar Hall element - the core 12a - the magnetic material of the tape 4.

Description

[Detailed description of the invention] (1) A magnetic core and a planar Hall element are arranged in a plane,
It is an object of the present invention to provide a magnetic head that can be constructed thinly with fewer patterning steps.

As a thin-film magnetic head for reproducing audio signals recorded on a magnetic tape, for example, as a POM, a reproduction-only magnetic head using, for example, a magnetoresistive element (hereinafter referred to as M-Shiko) or a planar Hall element has been developed. has been done. For example, as shown in FIG. 1, a magnetic head using an MTL element is made by depositing a thin film of an MR film 2 on a glass substrate 1, using the tape sliding surface 1a as a part, and depositing a thin film on the glass substrate 1. Terminals 3a and 3b of an AU etc. are provided at the terminals 3a and 3b, and the resistance value change of the MR element 2, which changes depending on the magnitude of the vertical component of the stray magnetic field of the magnetized magnetic tape 4, is used as a change in the electrical signal at the terminals 3a and 3b. The audio signal information recorded on the tape 4 is reproduced.

By the way, since the strength of the magnetic field received by the MR receiver 2 generally decreases with increasing distance from the magnetic surface of the tape 4 in the perpendicular direction, the magnitude of the output signal decreases exponentially (2), especially as the recording wavelength increases. This signal attenuation is large in a short region, and in the type shown in Figure 1, in which the output signal is obtained by bringing the MRR element 2 into direct contact with the tape 4, the MR element 2 is in direct contact with the tape 4 to obtain the output signal. 2 tape 4
It is designed to adhere to the surface.

However, since the thickness of the deposited film of the MRR element 2 is generally several hundred times or less, the structure in which the MR element 2 is brought into close contact with the tape 4 like the one shown in Figure 1 has a structure in which the MR element 2 slides against the tape 4. This has the disadvantage that it is easily worn out, generates noise, and has poor playback characteristics.

On the other hand, conventionally, as shown in FIG. 2, a core 6a made of permalloy or the like is formed on a glass substrate 5'', a non-magnetic material 7 is further formed on a part of the core 6a, and an MRR element 8 is deposited on a part of the core 6a. Further, an insulating film 9 is formed to surround the MR element 8, and there is a magnetic head in which a core 6b and a core 6a are formed on the insulating film 9, and a core 6C is formed on the insulating film 9. In this device, the tape sliding surface 10 is brought into contact with the tape 4 to form a ring-shaped magnetic path consisting of core 6a (3), one core 6 cm MR element 8 and core 6b, and the magnetic flux Cζ passing through this magnetic path changes. M
The change in the resistance value of the R element 8 is determined as an electric signal change from terminals (not shown) provided at both ends of the MR element 8.

In this case, since the Mll and element 8 do not come into contact with the tape 4, wear of the tape 4 can be avoided, but since it has a thin film laminated structure, many patterning steps are required, and there are many manufacturing steps. In addition, there was a drawback that the characteristics of the MT element 8 deteriorated due to repeated heating and cooling due to patterning. However, since the thin 1III surface after patterning has many irregularities, Mll.

There is a drawback that there are many steps such as polishing required before the element 8 is vapor deposited.

Incidentally, the magnetic field strength versus resistance value characteristic of an MR element is generally as shown in FIG. As is clear from the figure (, MR
If the point at which the magnetic field is zero is used as the operating point when applying a bias magnetic field to the cumulative element, (4) changes in the magnetic field from the tape, for example in one direction, cannot be taken out as changes in the resistance value in one direction, but the MT% element By applying a bias magnetic field HB in the figure and using this point as the operating point, a change in the magnetic field in one direction can be extracted as a change in the resistance value in one direction. In other words, a thin film magnetic head using an MR element must be used with a bias magnetic field applied, and therefore the bias point must be adjusted.Especially when configuring a multi-channel \RAD, this adjustment work is difficult. It has drawbacks such as requiring a lot of time.

On the other hand, NRu using a planar Hall element? There is a tn air head having a structure as shown in FIG. 1 or 2, but this also has the same drawbacks as mentioned above.

The present invention eliminates the above-mentioned drawbacks, and an embodiment thereof will be described below with reference to Figure gg4.

FIGS. 4 and 5 show a perspective view and a partial cross-sectional view of an embodiment of the thin film magnetic head according to the present invention. In the figure, 11 is a glass substrate, and a flat part 11a is located at the lower left end in the figure.
A protrusion 11b having a height h is integrally provided (5). 12a, 121) is a core made of high magnetic permeability material such as permalloy, and the core 12a is -
The core 12b is patterned on the right end of the substrate 11, the protrusion and the left end of the substrate 11], and the core 12b is patterned on the right end of the
lower part 12a' of core 12b, lower part 121)' of core 12b, substrate 1
1 are formed flush with each other to form a tape sliding surface 13.
Configure. Cores 12a', 12b', substrate 11
As shown in Figure 5, a view from above across the lower part of
The core 12a' and the core 121)' are offset in the running direction A of the tape 4 by the same distance as the height h of the protrusion 111). Note that the distance @h is the vertical component of the stray magnetic field that exists from the Ni pole to the S (i? pole), which is oriented in the running direction A of the tape 4 due to magnetization (its magnitude differs in the running direction A of the tape 4). It is designed to take out a sufficiently large difference between the two.

A planar Hall element 14 is deposited on the substrate 11 near the center thereof, and is electrically and magnetically connected to the cores 12a and 12b. 15a.

Reference numeral 15b denotes a hole electrode, which is deposited on the flat part 11a of the substrate 11, and the tip of the electrode 15a is connected to the output terminal 15a',
(6) The electrode 15b has an insulating film 16 between the core 12a and the substrate 11.
The terminal 15b' is located at the tip thereof through the terminal 15b'. Output terminals 15a' and 115b' are the core 12
a, provided in the longitudinal direction of 12b. As is well known, a planar Hall element generates an electromotive force in a direction perpendicular to a plane through which a current flows by applying a magnetic field in the same direction or in the opposite direction to the current.

The magnetic field strength versus resistance characteristic of the planar Hall element is similar to that of a general Hall element, for example as shown in FIG. That is, near the point where the strength of the magnetic field is zero (if one magnetic field is changed in one direction), the pole voltage can be extracted as a change in one direction.

A head configured in this way includes a tape l (magnetic material (e.g. N pole) - core 12b - planar Hall element 1).
4-Core 12a-A magnetic path of magnetic material (S pole) of tape 4 is formed, and planar pole cable]4 corresponds to the magnitude of the perpendicular component of the stray magnetic field due to the magnetic material magnetized according to the recording signal. °C Hall voltage is generated, and this Hall voltage is taken out from output terminals 15a' and 15b'. In this case, a current is passed through the magnetic path of (7) the planar Hall element 14 between the cores 12a and 12b.

Note that the strength of magnetization in the direction perpendicular to the running direction of the tape 4 is the same, so even if the cores 12a and 12b' are configured to be shifted in the direction perpendicular to the direction A, the magnetization strength is the same in the direction perpendicular to the running direction of the tape 4, so even if the cores 12a and 12b' are configured to be shifted in the direction perpendicular to the direction A, the magnetization strength is the same in the direction perpendicular to the running direction of the tape 4. This is substantially the same as the presence of the core 12a, and the same as that of a magnetic head having a gap of distance d between the upper end surface of the core 12a and the lower end surface of the core 12b'.

In this way, the core 12a is simply placed on the surface of the substrate 11.

12b, because it has a simple structure in which the planar Hall elements 14 are patterned in substantially the same plane, the number of manufacturing steps is smaller than that of a structure in which several layers are laminated as shown in FIG.
Moreover, it can be constructed thinly, and the planar Hall element 1
4 is not on the tape sliding surface 13, so there is no risk of wear as in the one shown in the first figure.

Also, the Hall element is as shown in Figure 6. Since changes in the magnetic field near zero fB field can be extracted as positive and negative Hall voltage changes, the point of zero magnetic field can be used as the operating point (8), and a bias magnetic field can be applied, such as in a thin-film magnetic head using an MR multilayer element. There's no need.

Incidentally, if a plurality of pairs of cores and planar Hall elements configured as shown in FIG. It can be used as a magnetic head.

As described above, the thin film magnetic head of the present invention has a magnetic core and a planar Hall element disposed in a thin film form on a substrate substantially in the same plane, and each core is disposed in a plane perpendicular to the plane of the substrate. and the end of the substrate are flush with each other to serve as a magnetic tape sliding surface, and at least one set of substantially planar magnetic paths formed by connecting two cores via a planar pole element is provided. , because the ends of the tape sliding surfaces of adjacent cores in the magnetic path are shifted in a direction perpendicular to the plane of the substrate, it is possible to simply pattern the cores and planar Hall elements on the surface of the substrate in approximately the same plane. The core, non-aH material, M
It requires fewer patterning steps than the conventional method in which R elements, insulating films, etc. are laminated (9), and can be constructed thinner than the conventional method. Because of this, the output voltage can be obtained without applying a bias magnetic field, and Ml'L
The device can be made compact because the element is made of high quality and a bias magnetic field generation source is not required. Moreover, there is no need to adjust the bias point, and it is possible to create a magnetic head with a particularly large number of channels. It has features such as being easy to use.

[Brief explanation of the drawing]

1 and 2 are perspective views of each side of a conventional magnetic head, FIG. 3 is a characteristic diagram of a magnetoresistive element, and FIGS. 4 and 5 are perspective views of an embodiment of the magnetic head of the present invention, respectively. and its partial cross-sectional view, Figure @6 is a characteristic diagram of the planar Hall element. 4.Fist-magnetic tape, 11-.Crow board, 111)
...Protrusion, 12a, 12a', i21], 1
21)' arm Magnetic core, 13--@tape sliding surface, 14-1l◆Planar Hall element, 1.5a,
151) am-hole electrode, 15a', 15b'
Fist: Output terminal. (10)

Claims (1)

[Scope of Claims] (I) A magnetic core and a planar Hall element are disposed in a thin film form substantially on the same plane on a substrate, and the respective ends of the core and the The edge of the substrate is flush with the magnetic tape as a sliding surface, and at least one set of substantially planar magnetic paths formed by connecting the two cores via the planar Hall element is provided, 1. A thin-film magnetic head characterized in that end portions of adjacent cores in a magnetic path that serve as magnetic tape sliding surfaces are offset in a direction perpendicular to the plane of the substrate. (2) The thin film magnetism according to claim 1, characterized in that the magnetic cores are arranged such that a plurality of sets of the magnetic paths are formed in a direction perpendicular to the running direction of the magnetic tape. head.