JPH02130712A - Magneto-resistance effect element - Google Patents

Abstract

PURPOSE:To improve the output of a magneto-resistance effect element by not providing a thin film of a soft magnetic substance for guiding magnetic fluxes of signals, but only protruding a magnetism sensible section corresponding to the signal recording track width on a magnetic recording medium at the central part of a magneto- resistance effect film from the surface of the element facing the medium. CONSTITUTION:After an insulating layer 2 of an Al2O3 film, etc., is formed to a thickness of 0.1-0.4mum on a base plate 1 which is made of a magnetic substance of ferrite, etc., and also works as a lower magnetic shield, a film 3 of a good conductor of Al, Cu, etc., for impressing a bias magnetic field upon a magneto-resistance effect film 5 is formed and patterned to a thickness of 0.05-0.2mum on the layer 2. Then, after forming an insulating layer 4 similar to the layer 2 on the film 3, the magneto- resistance effect film 5 of a thin film of an Ni-Fe alloy, etc., is formed and patterned to a thickness of 10-100nm on the insulating layer 4. Thereafter, a magnetic substance belt 5' for guiding magnetic fluxes having a width almost equal to the width of a magnetism sensible section 6 is provided on the side opposite to the medium facing surface 8 of this magneto-resistance effect element by protruding the magnetism sensible section 6 of the effect film 5 from the medium facing surface 8 and retreating the other section from the surface 8.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magnetoresistive element used in a read-only magnetoresistive head, and particularly to a magnetoresistive element suitable for magnetization reproduction with a narrow track width. Regarding.

[Conventional technology]

The conventional magnetoresistive element is disclosed in Japanese Patent Application Laid-Open No. 57-181425.
and JP-A No. 59-24427, a soft magnetic material for introducing magnetic flux for guiding signal magnetic flux from a magnetic recording medium to a magnetic sensing part of a magnetoresistive element provided apart from a medium facing surface. A thin film was provided separately.

In addition, as described in Japanese Patent Application Laid-Open No. 50-65211, in order to increase the output of the magnetoresistive element and reduce noise,
The magnetoresistive film used in the magnetoresistive element has two layers with an insulating layer interposed therebetween, and the difference or sum of the outputs of each magnetoresistive film is amplified.

[Problem to be solved by the invention]

In the prior art described in JP-A No. 57-181425,
An insulating layer is provided between the soft magnetic thin film for introducing signal magnetic flux and the magnetically sensitive portion of the magnetoresistive film. For this reason, the magnetic resistance between the two increases, and the amount of signal magnetic flux introduced into the magnetically sensitive portion substantially decreases. Therefore, there is a problem in that the signal reproduction efficiency of the magnetoresistive element is reduced.

Furthermore, in the prior art described in JP-A-50-65211, since there is a time difference in the absorption of signal magnetic flux by each magnetoresistive film formed in two layers, it is inevitable that each magnetoresistive A phase difference occurs between the output waveforms of the effect film. For this reason, there has been a problem in that the output waveform of the magnetoresistive element obtained by amplifying the difference or sum of the outputs of the respective magnetoresistive films is greatly distorted.

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetoresistive element which eliminates the above-mentioned problems and is suitable for magnetization reproduction with a narrow track width.

[11! ! Means for Solving the Problem] In order to achieve the above object, the present invention does not provide a soft magnetic thin film for introducing signal magnetic flux, and the signal recorded on the magnetic recording medium at the center of the magnetoresistive film is Only the magnetically sensitive portion corresponding to the recording track width of is made to protrude from the medium facing surface, and a lead wire for introducing a detection current is provided on the remaining magnetoresistive film.

Further, the magnetoresistive film is formed into two layers with an insulating layer interposed therebetween, and a similar lead wire for introducing a detection current is provided in the lower magnetoresistive film, however, the medium facing surface is insulated at the protrusion near it. A more favorable result can be obtained by removing the layer and bringing the upper and lower magnetoresistive films into contact with each other.

[Effect]

In the present invention, as described above, by protruding only the magnetically sensitive part of the magnetoresistive film without providing a soft magnetic thin film for introducing signal magnetic flux, the signal magnetic flux from the recording medium is sucked in from this protruding part and directly transmitted. It becomes possible to guide the magnetic field to the magnetically sensitive part of the magnetoresistive film. Furthermore, by protruding the internal body of the magnetically sensitive part in this way, it becomes possible to reduce the demagnetizing field of the magnetically sensitive part.

Thereby, the signal magnetic flux can be guided to the magnetic sensing part without decreasing the amount of signal magnetic flux.

In addition, in a two-layer magnetoresistive film, by removing the insulating layer between the magnetoresistive films at the medium facing surface of the protrusion and its vicinity, and bringing the upper and lower magnetoresistive films into contact with each other, the signal magnetic flux can be guided to the magnetically sensitive parts of the upper and lower magnetoresistive films at the same time. Thereby, even when the difference or the sum of the outputs of the upper and lower magnetoresistive films is amplified, no distortion occurs in the resulting output waveform.

【Example〕

Hereinafter, the present invention will be explained in detail with reference to Examples.

Embodiment 1 FIG. 1(a) is a front view of a magnetoresistive element according to an embodiment of the present invention, and FIG. 1(b) is a sectional view taken along line AA' in FIG. 1(a).

In this example, a soft magnetic thin film for the lower magnetic shield is laminated on a substrate 1 made of a magnetic material such as ferrite that also serves as a lower magnetic shield (or on a non-magnetic material such as ceramics through an insulating layer such as an AΩ208 film). (It may also be possible to use a On this substrate l, AQxOsm and 5iOz
The insulating layer 2 made of a film or the like is formed by sputtering or the like to a thickness of 0.1 to
Laminate 0.4 μm thick. Thereon, a conductor film 3 made of a good conductor such as Aff or Cu for applying a bias magnetic field to the magnetoresistive film 5 is laminated to a thickness of 0.05 to 0.2 μm by vapor deposition or sputtering.

Then, it was patterned into a predetermined shape using photolithography and dry etching.

Furthermore, an insulating layer 4 having a thickness of 0.1 to 0.2 μm and made of the same material as the above-mentioned insulating layer N2 is formed thereon. Then, on this insulating layer 4, an N1-Fa alloy thin film or a Ni-G
o A magnetoresistive film 5 having a magnetoresistive effect, such as an alloy thin film, is formed by a vapor deposition method, a sputtering method, etc.
The layers were laminated to a thickness of 00 nm, and patterned into a predetermined shape by photolithography and dry etching.

The feature of this shape is that only the magnetically sensitive portion 6 on the magnetoresistive film protrudes to the medium facing surface 8 that faces the magnetic recording medium 7, and the other portions are retracted from the medium facing surface 8. On the side opposite to the medium facing surface 8 of 6, a band 5' of magnetic material for guiding magnetic flux is provided at an interval of 0.5 to 1 .mu.m, and the width is approximately equal to the width of the magnetically sensitive portion 6.

The width of the protruding magnetically sensitive portion 6 is equal to the track width on the magnetic recording medium 7, and the protruding length may be equal to or greater than the maximum wear amount when the magnetoresistive element is operated on the magnetic recording medium. However, it is desirable that the length of the protrusion be optimized by the device using the present invention. For example, when used in devices with low wear such as magnetic disk drives,
The length of the protrusion is preferably in the range of 1 to 10 μm, but in this case, the width of the protrusion is also preferably 10 μm or less. In addition, when used in a device with a large amount of wear such as a magnetic tape device, it is desirable that the length of the protrusion is set to the amount of wear plus 2 to 5 μm in accordance with the amount of wear.

Note that the easy magnetization direction of the magnetoresistive film 5 was parallel to the longitudinal direction of the magnetoresistive film 5.

Then, a current introducing line 9 made of AQ or Cu for introducing a signal detection current is formed on the film other than the magnetically sensitive part 6 of the magnetoresistive film 5, and is further made of an Al2011 film or SiO.
An insulating layer 10 consisting of two films is laminated with a thickness of 0.1 to 0.8 μm, and finally a soft magnetic thin film 11 for the upper shield is laminated (or a soft magnetic material such as ferrite is laminated with an adhesive or the like). The production of the magnetoresistive element 12 (which may be bonded) has been completed.

In the magnetoresistive element 12 according to this embodiment, the signal magnetic flux 13 leaking from the magnetic recording medium is sucked in through the magnetoresistive film protruding from the medium facing surface 8 and guided directly to the magnetically sensitive part 6. A magnetic strip 5' for guiding the magnetic flux through the
lead to. As a result, in this magnetic sensing part 6, the signal magnetic flux guided to the magnetic sensing part, the resistance of the magnetic sensing part 6 changes due to the magnetoresistive effect, and the detection current introduction line 9 is connected to the resistance. Detects voltage changes corresponding to changes. This makes it possible to read the signals recorded on the tour magnetic recording medium 7. At this time, an appropriate current is applied to the conductor film 3 in the magnetically sensitive part 6 of the magnetoresistive film 5 so that the direction of magnetization in the magnetically sensitive part forms an angle of approximately 45° with respect to the direction of the detection current. It is necessary to apply a bias magnetic field.

According to this embodiment, as described above, the signal magnetic flux 13 can be directly guided from the magnetoresistive film 5 protruding from the medium facing surface 8 to the magnetic sensing part 6, so the amount of signal magnetic flux absorbed from the medium facing surface magnetically sensitive part 6 without reducing due to leakage.
This has the effect of increasing the output of the magnetoresistive element 12 more than that of a conventional magnetoresistive element.

Embodiment 2 FIG. 2(a) is a front view of a magnetoresistive element according to another embodiment of the present invention, FIG. 2(b) is a sectional view taken along line BB' in FIG. 2(a), and FIG. is a sectional view taken along line CC' in FIG.

In this example, a groove 14 for providing a detection current lead-in line 9 is formed on an insulating layer 2 laminated on a substrate 1 similar to that in Example 1 by photolithography and dry etching. A current introduction line 91 made of AQ, Cu, or the like is provided in the groove 14. Thereafter, a first layer of magnetoresistive film 51 made of Ni-Fe alloy or Ni-Co alloy is laminated to a thickness of 10 to 1100 nm by vapor deposition or sputtering, thereby forming the structure of Example 1.
It was patterned into a similar shape using the same method as in the case of .

At this time, current is introduced into the magnetoresistive film 51! 91 so that they are electrically connected to each other. Next, an insulating layer 15 of the same quality as the insulating layer 2 is laminated thereon to a thickness of 0.05 to 0.4 μm, and the second layer magnetoresistive film 52 is stacked on top of the first layer magnetoresistive film 51. Same thickness.

It was formed into the same shape and by the same manufacturing method.

What is important here is that the second layer magnetoresistive film 5
2, before laminating the medium facing surface 8 and the insulating layer 15 in its vicinity.
By opening a through hole 16 inside, the protrusion of the second layer magnetoresistive film 52 and the protrusion of the first layer magnetoresistive film 51 are brought into contact with the medium facing surface 8 and its vicinity. be. The length and width of the protrusion are 1 as in Example 1.
It is desirable to optimize the value depending on the device using this embodiment, and the value is the same as in the first embodiment. Note that the easy magnetization direction of the second layer magnetoresistive film 52 was parallel to the long axis direction of the pattern similarly to the first layer magnetoresistive film 51. Then, the detection current introduction line 92 was provided on the second layer magnetoresistive film 52, but at this time, the detection current lead-in line 92 was provided on either one end side of the magnetoresistive film 52, in this example, on the right end side. A through hole 17 is opened in the insulating layer 15, and the detection current introducing line 92 and the first layer magnetoresistive film 51 are connected to each other.
The detection current lead-in line 91 on the lower right end side is short-circuited.

Finally, in the same manner as in Example 1, the insulating layer 10 was laminated and the upper magnetic shield layer 11 was formed to complete the production of the magnetoresistive element 18. In this example, unlike the case of Example 1, the conductive film 3 for applying a bias magnetic field is not provided, but this is because the magnetoresistive film has two layers, so that each magnetoresistive film can detect the This is because when current flows, there is a mutual biasing effect.

Magnetoresistive element 18 according to this embodiment as described above
Now, the magnetoresistive film 51.5 protruding from the medium facing surface 8
Signal magnetic flux 13 simultaneously leaking from magnetic recording medium 7 from 2
is sucked in and guided directly to the magnetically sensitive parts 61 and 62 of the upper and lower magnetoresistive films, and further guided through the magnetically sensitive parts 61 and 62 to the magnetic bands 51' and 52' for magnetic flux guide.

At this time, at the branch point d, since the upper layer and the lower layer magnetoresistive films 51 and 52 are made of the same material and have the same film thickness and shape, almost the same amount of signal magnetic flux is branched to the magnetically sensitive parts 61 and 62. There will be an intrusion. And the magnetic sensing part 61
and 62, detecting a voltage change corresponding to each resistance change from the current introduction lines 91 and 92 by utilizing the fact that the resistance of the magnetic sensing parts 61 and 62 changes due to the magnetoresistive effect due to the signal magnetic flux, Furthermore, the signals recorded on the magnetic recording medium 7 can be read by differentially amplifying the respective 8-power voltages.

At this time, by passing the same detection current through the upper and lower magnetoresistive films 51 and 52 in the same direction,
Equivalent mutual bias magnetic fields act to reverse the directions of magnetization in each magnetoresistive film, making differential amplification possible. Further, the amount of resistance change in the magnetically sensitive parts 61 and 62 is the same since the same amount of signal magnetic flux enters the magnetically sensitive parts 61 and 62 as described above.
The amount of voltage change detected in the current introduction lines 91 and 92 corresponding to each resistance change of 62 degrees is equivalent.

Further, the signal magnetic fluxes simultaneously sucked in from the protrusions of the magnetoresistive films 51 and 52 on the medium facing surface 8 reach the respective magnetically sensitive parts 61 and 62 simultaneously.

Therefore, the phases of each voltage change detected by the current introduction lines 91 and 92 also do not have a one phase difference.

According to this embodiment, in addition to the same effect as described in Embodiment 1, it is possible to simultaneously guide the same amount of signal magnetic flux to the magnetically sensitive parts of the upper and lower magnetoresistive films as described above. Even when the output voltages of the upper and lower magnetically sensitive parts are differentially amplified, the differential waveform is not distorted and a high output can be obtained.

Embodiment 3 FIG. 3 shows a sectional view of a magnetoresistive element according to another embodiment of the present invention. The cross-sectional view in FIG. 3 is the same as in FIG. 2 (c
This embodiment corresponds to the cross-sectional views shown in , ), and shows detection current lead-in lines formed at both ends of the upper and lower magnetoresistive films 51 and 52 in the magnetoresistive element 18 of embodiment 2. The upper and lower detection current lead-in lines formed at either end of the 91 and 92 are shared by a common current lead-in line. The other configurations are the same as in the second embodiment, and the operation and effects are completely the same as in the second embodiment.

〔Effect of the invention〕

According to the present invention, the signal magnetic flux leaking from the magnetic recording medium can be guided to the magnetically sensitive part of the magnetoresistive element without its amount being reduced, thereby achieving the effect of increasing the output of the magnetoresistive element. Furthermore, since the same amount of signal magnetic flux can be guided to the magnetic sensing part of the two-layered magnetoresistive element at the same time, even when the output voltage of the magnetic sensing part is differentially amplified, the differential waveform can be maintained. It has the effect of not causing distortion. Therefore, it is possible to further increase the output of the magnetoresistive element, and it is possible to manufacture a magnetoresistive element suitable for narrow track recording and reproduction.

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) are a front view and a sectional view of an element according to an embodiment of the present invention, and FIGS. 2(a) and 2(b). (c) is a front view and a sectional view of an element of another embodiment of the present invention, and FIG. 3 is a sectional view of an element of still another embodiment of the invention. 1... Substrate, 2, 4, 10.15... Insulating layer, 3.
... Conductor layer, 5... Magnetoresistive film, 6... Magnetically sensitive part, 7... Magnetic recording medium, 9... Detection current introduction line,
11... Upper magnetic shield layer, 12.18... Magnetoresistive element, 13... Signal magnetic flux.

Claims (1)

[Claims] 1. A magnetoresistive element that reads a signal magnetic field from a magnetic recording medium using the magnetoresistive effect of a ferromagnetic thin film, comprising the above-mentioned ferromagnetic thin film used in the magnetoresistive element. The shape of the magnetoresistive film is such that only the magnetically sensitive part corresponding to the recording track width of the signal recorded on the magnetic recording medium at its center protrudes to the surface facing the medium, and the remaining magnetoresistive film is detected. A magnetoresistive element characterized by being provided with a lead wire for introducing current. 2. The magnetoresistive film is made of two layers with an insulating layer in between, and the lower magnetoresistive film is also provided with a similar lead wire for introducing current. Claim 1 characterized in that the upper layer and the lower layer magnetoresistive film are in contact with each other except for
The magnetoresistance effect element described in . 3. Short-circuit the upper and lower detection current lead wires formed on the right end or left end of the two layers of magnetoresistive films to each other, so that the signal magnetic field from the magnetic recording medium causes the upper layer and 3. The magnetoresistive element according to claim 2, wherein an output voltage corresponding to a change in resistance of an underlying magnetoresistive film is differentially amplified and read.