JPS59112421A - Magnetic head - Google Patents

Abstract

PURPOSE:To obtain a reproducing output having no error by providing a magnetic bias in the opposite direction to each other, to two MR element placed in the vicinity of the other end face of a yoke contacting with a magnetic recording medium, and outputting a difference of a resistance variation quantity of two MR elements. CONSTITUTION:A titled magnetic head contains a yoke 11 consisting of a high permeability magnetic material thin film, two ferromagnetic magneto-resistance effect (MR) elements 12, 13, and a conductive body stripe 14 for forming a magnetic bias of the opposite direction. They are installed on a head slider or in its inside, and an opposed surface 15 is opposite to a magnetic recording medium 16. The MR elements 12, 12 are placed so as to be adjacent to each other, in the vicinity of the other end face 18 of the yoke 11, and a conductive stripe 14 is placed between them. A variation of resistance due to a temperature is determined by only a resistance temperature coefficient of an MR element material, therefore, the resistance variation of the MR elements 12, 13 becomes the same phase. Accordingly, a reproducing output which is not influenced by a temperature variation can be obtained by outputting a difference of the resistance variation quantity of both elements.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic head using a ferromagnetic magnetoresistive element.

A ferromagnetic magnetoresistive element (hereinafter abbreviated as a wind element) is an element whose electrical resistance changes depending on an applied magnetic field, and is being applied as a reproducing magnetic head because of its high detection sensitivity. Typical materials include N i Fe alloy and N
I-Co alloys are well known, and these have a resistance change rate of about 2 to 5 degrees due to a magnetic field, but at the same time they also change resistance depending on temperature, and a temperature change of about 4 to 10'C is due to a signal magnetic field. It reaches a level comparable to 1. In order to eliminate spurious signal components caused by such temperature changes, conventional magnetic heads distribute two MR elements as shown in Figure 1 to generate a differential output, that is, the difference in resistance change I. There is a known method for outputting . This takes advantage of the fact that a signal magnetic field is applied to the MR element 1 closer to the magnetic recording medium 3, whereas no magnetic field is applied to the MR element 2 farther from the magnetic recording medium 3, and the differential is This eliminates in-phase resistance changes caused by temperature changes. However, although this method can cope with slow, wide-area temperature changes, it cannot cope with local, instantaneous temperature changes caused by sliding with a magnetic He recording medium or collision with minute protrusions, such as in a magnetic head. For M'
Because of the time difference between the temperature rises of R elements 1 and 2, the generation of spike-like pseudo signals was unavoidable.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and to provide a magnetic head that can perform more complete temperature compensation and provide error-free reproduction output.

The magnetic head of the present invention includes a yoke made of a high magnetic permeability magnetic thin film having one end surface on a surface facing a magnetic recording medium, and two M
It is characterized by having an R element and a mechanism for forming magnetic biases in opposite directions to the two MR elements, and outputs the difference in the amount of resistance change between the two MR elements. .

Next, embodiments of the present invention will be explained with reference to the drawings.

Referring to FIG. 2, the first 5.1 embodiment of this evening consists of a yoke 11 made of a high permeability magnetic thin film, two 4R elements 12 and 13, and a magnetic via 7° in the opposite direction. The conductive stripes 14 serve as a mechanism for forming the conductor stripes. Although they are omitted for convenience in this country, these are installed on or inside the head slider, and the facing surface 15 faces the magnetic recording body 16. "l-ri11 no1tsu f
7) 4 sides 1714. ”:, 17) Illusion 1ijJ Th,i
It's on l 5. The IR spades 12 and 13 are placed near the other end surface 18 of the yoke 11, and are arranged in a manner that they are closely spaced.
,! ·is.

Next, this operation will be explained. The magnetic field from the magnetization of the magnetic recording medium 16 magnetizes the yoke 11, and the magnetic field produced by this magnetization further magnetizes the dish element 12.13. It is well known that if the magnetization direction of the MR element is magnetically biased so as to be inclined by 45'' with respect to the direction of the sense current flowing therein, a linear output with better sensitivity can be obtained.■Element 1
2.13 are in opposite directions, that is, M
Since the R element is magnetically biased at 45 degrees and -45 degrees with respect to the sense current direction, resistance changes in opposite phases occur depending on the magnetic field from the yoke 11. On the other hand, since the change in resistance due to temperature is determined only by the temperature coefficient of resistance of the kite element material, the changes in resistance of the kite elements 12 and 13 are in the same phase.

Therefore, the differential of the two MR Iikos 12 and 13 is taken. That is, by using the difference in resistance variation between the two as the output, it is possible to obtain a reproduction output that is not affected by temperature changes. Note that the minimum bit length of the magnetic recording medium that can be reproduced by the magnetic head element, that is, the resolution, is approximately the distance between the general KMR element and the magnetic recording medium, so it is usually 10 units from aμ, but the magnetic head of the present invention In this case, since the wind element is indirectly magnetized by the yoke 11, it is possible to reduce the noise to below 100 m.

Next, the effect of removing the shadow of the magnetic head will be explained with reference to FIG. 3 while comparing it with a conventional magnetic head. Figure 3(a) is b'
r is a sectional view of the embodiment shown in Figure 2, and Figure 3 (bl
2 is a sectional view of the conventional configuration example shown in FIG. 1. FIG. As mentioned above, when the temperature changes over a wide area and slowly, the MR chord 2
The temperature is quiet between 1 and 22 or 23 and 24, and there is no difference in resistance change, and by adopting a differential configuration, the temperature difference between the magnetic head of the present invention and the conventional one is eliminated. can. However, in a magnetic head, the magnetic recording medium 25.2
6 or contact with minute protrusions, which corresponds to a small heat source moving at high speed on the surface of the medium facing surface 27,28. When this heat source passes near the element 2, the element 23 comes into contact with the point-shaped heat source, so it
A sudden temperature rise occurs as shown in R8 of 1. On the other hand, the R elements 2], 22 and 24 are connected to the medium facing surfaces 27, 2.
R+ in Figure 3(c) because they are far from 8.
, R2 and R4 in Figure 3 (dl), the changes are relatively slow (especially since the MR elements 21 and 22 are arranged close to each other, the changes are almost the same. Therefore, the MR elements In the conventional magnetic head having a differential configuration of 23 and 24, a spike-like pseudo signal output as shown by ΔR2 in FIG.
As shown by ΔR8 in Figure (e), it is completely unaffected by sudden and local temperature changes.

In this embodiment, the conductor stripe 14 is a mechanism for making the resistance changes of the MR elements 12 and 13 due to the magnetic field from the yoke 11 have opposite phases to each other, and the mechanism for forming bias magnetization in such opposite directions can be further modified. Both are possible. FIGS. 4(a) and 4(b) are diagrams showing, for the sake of simplicity, only the stage in front of which the MR element and magnetic bias are formed as an example of such a modification.

The one shown in FIG. 4 (&) is a so-called barber pole MR in which conductive bars 33 and 34 are provided on the surfaces of wind elements 31 and 32, respectively, making a distance of approximately 45'' from the longitudinal direction of the elements.
This is a configuration known as a foundling. When the magnetization directions of the MR elements 31 and 32 are the same in the X direction when no signal magnetic field is applied, the conductor bars 33 and 34 are arranged so as to be orthogonal to each other, and conversely, the MR element 3
When the magnetization directions of 1.32 are set to be opposite to each other in the X direction, a predetermined reverse bias magnetization can be obtained by making the conductors 33 and 34 parallel to each other. Furthermore, the one shown in FIG. 4(b) is constructed so that currents flow in the same direction through the MR elements 35 and 36. ■Element 35.
36 are placed close to each other, so the sense vL flow I flows to detect the respective resistance change amounts.

and I, bias magnetic fields H1 in opposite directions to each other &
, can be applied to form a predetermined reverse bias magnetization. Although the degree of freedom in setting the bias magnetization in the modified example of Kowara is slightly lower than that shown in Fig. 3, it has the advantage of not requiring an extra number of electrode terminals. There is.

Furthermore, in the embodiment shown in Figures 2 and 3 (al), the yoke is placed only between the MR zero and the magnetic recording medium, but this can be reversed as shown in Figure 5 (IL). If a back yoke 44 is installed on the side as well, it is possible to further improve the detection sensitivity of 42.43 of the 1-Sho element.In addition, the distance between the MTt element and the yoke should be kept as small as possible to maintain electrical insulation. It is preferable to make one, but it is easier to make the fifth one.
As shown in Figure (b), the MR elements 46, 47 and the yoke 45
There is no big difference in characteristics even if the shape is made slightly different.

In the above embodiments, the MR cumulative element is a thin film of iron, nickel, and cobalt, which have a large resistance change rate, and is typically made of NiFe or NiCo.
The film thickness is from 200^ to 1000^, and the stripe width is from several doors to 10JI. In addition, the film thickness of the yoke ranges from several thousand years to several sevens.
Any magnetic material with a permeability of about 11 is sufficient, and iron, nickel, aluminum, and cobalt alone or alloys can be used.
Furthermore, gold, copper, aluminum, etc. are suitable as the conductor. These can be manufactured into a predetermined shape and arrangement using thin film formation techniques such as vapor deposition, sputtering, and plating, and microfabrication techniques such as photoetching.

As described above, the present invention includes a yoke made of a high-permeability magnetic thin film having one end surface on a surface facing a magnetic recording medium, and two MR elements disposed close to the other end surface of the yoke. , and a mechanism for forming magnetic biases in opposite directions to the two MR elements.
By using the difference in resistance change between two German elements as the output,
Even if there is a local instantaneous temperature change, it has the effect of being able to obtain a playback output signal that does not suffer any effects and has no effect.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the basic structure of a conventional magnetic head, and FIG. 2 is a perspective view showing the basic structure of an embodiment of the present invention.
:l lkl (al and (clket#: 2 m4i
i(yr:, sectional view of the example and its output, t
A3 J (bl and (dl are the 1I7T surface failure and its output of the conventional example shown in Figure 1), ai'+ 4N'i (a)
, (b) are diagrams showing an example of a mechanism for forming a magnetization bias in the opposite direction (10), and Figures 5 (a) and (b) are cross-sectional views showing examples of the arrangement of the yoke and the seed element It is a diagram. In the figure, 1, 2.12.13.21.22.23.
24.31.32.35.36.42.43.46 and 47 are kite elements, 3% 16.25 and 26 are magnetic recording media, 11.30.41 and 45 are yoke, 44 is back Yoke, 15.27.28.48 and 49 are surfaces facing the magnetic recording medium, 17 is one end surface of the yoke, 18
is the other end surface of the yoke, 14 and 29 are conductor stripes that form magnetization biases in opposite directions, and 33 whisper fT21 Fig. 2 12 13 Fig. 3 2C? (αn
(h) 4th 2゜(α) 5th Cku) tb)

Claims (1)

[Claims] 1. A yoke made of a high magnetic permeability magnetic thin film having one end surface on the surface facing the magnetic recording medium, and two ferromagnetic magnetoresistors arranged close to the other end surface of the yoke. an effect element, and a mechanism for forming magnetic biases in opposite directions to the two ferromagnetic magnetoresistive elements, and outputs the difference in resistance change between the two ferromagnetic magnetoresistive elements. A magnetic head characterized by: 2. The magnetic head according to claim 1, which has a conductive stripe arranged between two ferromagnetic magnetoresistive elements as a mechanism for forming a magnetic bias. 3. As a mechanism for forming a magnetic bias, approximately 453 mm is placed on the surfaces of two ferromagnetic magnetoresistive elements in the longitudinal direction of the elements.
2. A magnetic head according to claim 1, further comprising a conductive bar. 4. The magnetic head according to claim 1, which includes a mechanism for supplying current in the same direction to each of the two ferromagnetic magnetoresistive elements as the mechanism for forming the magnetic bias.