JPH0785428A - Magnetoresistance effect magnetic head - Google Patents

Abstract

PURPOSE:To simplify the constitution and prevent noises from a control circuit or the like, by providing a fixed resistance for regulating the amount of a sense current fed from a constant voltage circuit, or a fixed resistance and a capacitor for a reproducing circuit at a portion of a lead conductor of an MR element. CONSTITUTION:An MR element 11 and a fixed resistance film 12 are simultaneously formed on a substrate. A pair of forked lead conductors 13 are formed out of an Au film. A part indicated by a chain line in the drawing is an MR head 15. One end of the forked lead conductor from the MR element 11 having the fixed resistance 12 is connected to a constant voltage source, while the other is grounded. The lead conductor without a fixed resistance is, via a DC cut-off capacitor 14, connected to a reproducing circuit 16. When the MR head 15 moves on a recording medium, voltages at both ends of the MR element 11 are changed by a magnetic flux due to a magnetic recording, which are processed by the reproducing circuit 16 thereby to output a reproducing signal. In the constitution, the reproducing circuit for the MR head is simplified and, electromagnetic noises are not mingled from the outside through the reproducing circuit, so that a high-quality reproducing signal is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive effect magnetic head used in magnetic disk devices, magnetic tape devices and the like.

In recent years, with the increase in capacity of magnetic disk devices, which are external storage devices for computers, high performance magnetic heads have been required. To satisfy this requirement,
Attention has been focused on a magnetoresistive effect magnetic head (hereinafter referred to as an MR head) that can obtain a high output regardless of the speed of a recording medium.

[0003]

2. Description of the Related Art A conventional MR head structure and a circuit for supplying a sense current to the MR head have the structures shown in the front view of the main part of FIG. 6A and the circuit diagram of the main part of FIG. 6B. There is. In the figure, 11 is a magnetoresistive effect element (hereinafter MR
Element), 12 is a fixed resistor that defines the sense current,
Reference numeral 13 is a lead conductor, 14 is a capacitor for cutting a DC component, and 16 is a reproducing circuit constituted by an integrated circuit or the like.

In this structure, the head is composed of the MR element 11 and the lead conductor 13 as shown in FIG. 7A. To reconstruct a signal using this, as shown in FIG. The MR head 15 and the fixed resistor 12 for defining the sense current are connected in series to supply the sense current, and only the signal component is supplied to the reproducing circuit 16 through the capacitor 14. MR from media here
When a signal magnetic field enters the element 11, the resistance value of the MR element 11 changes, and a signal is detected as a voltage change across the MR element 11.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the R head, the structure of the reproducing circuit is more complicated than in the case of an inductive head that does not have a conventional capacitor and fixed resistance, and electromagnetic noise mixed from these circuit components flows into the MR element, which reproduces it with the signal. As a result, noise is generated and the S / N ratio of the reproduced signal deteriorates.

The present invention can simplify the structure of the reproducing circuit,
Moreover, it is intended to realize an MR head capable of reproducing a signal without causing noise from the control circuit of the device on the MR element.

[0007]

In the magnetoresistive effect magnetic head of the present invention, in the magnetoresistive effect magnetic head having the magnetoresistive effect element 11, the amount of sense current supplied from the constant voltage circuit is specified. Fixed resistor 12, or DC blocking capacitor 1 for the fixed resistor 12 and the reproducing circuit
4 is provided in the middle of the lead conductor 13 of the magnetoresistive effect element 11.

In addition to the above, the fixed resistor 12
However, a part of the magnetoresistive effect element pattern is used.

By adopting this configuration, it is possible to obtain an MR head which can simplify the configuration of the reproducing circuit and can reproduce the signal without noise from the control circuit of the apparatus on the MR element.

[0010]

In the present invention, as shown in FIGS. 1 and 4, one or both of the fixed resistor 12 for defining the sense current and the direct current cutoff capacitor 14 for the reproducing circuit are connected to the lead conductor of the magnetoresistive effect element 11. Since it is provided in the middle of 13, it is possible to omit one or both of the fixed resistor and the capacitor of the reproducing circuit, simplify the configuration, and suppress electromagnetic noise.

[0011]

FIG. 1 is a diagram showing a first embodiment of the present invention, (a) is a front view of a main portion, and (b) is a circuit diagram shown together with a reproducing circuit. The MR head according to the present embodiment is, as shown in FIG.
The R element is composed of a pair of lead conductors 13 having one end connected thereto and supplying a sense current, and a fixed resistor 12 provided in the middle of each of the pair of lead conductors. It should be noted that the pair of lead conductors 13 are bifurcated, and the one provided with a fixed resistor is connected to the sense current terminal,
The one without anything continues to the playback terminal.

This embodiment is prepared as shown in FIG. First, as shown in FIG. 3A, a film serving as the MR element 11 and the fixed resistor 12 is simultaneously formed on a substrate (not shown) such as a NiFe film. In this case, for example, the resistance value of the fixed resistor is set to 2
When it is set to 50Ω, the resistivity of NiFe is 25μΩ ・ c
Assuming that m and the NiFe film thickness of the MR element part are 300Å, the width may be 3 μm and the length may be 90 μm. As a result, the fixed resistance can be formed only by changing the mask pattern and without any special process. Next, when a pair of lead conductors 13 divided into two lids are formed of Au film as shown in FIG.
A fixed resistor 12 is arranged on one side of the lid.

The MR element of the present embodiment thus constructed is used as shown in FIG. 1 (b). In the figure, the portion surrounded by the dotted line is the MR head 15, and one of the lead conductors from the MR element 11 having the fixed resistance 12 is connected to the constant voltage power source and the other is connected to the ground, and the lead conductor having no fixed resistance is DC blocking capacitor 1
4 is connected to the reproducing circuit 16.

Then, when the MR head 15 moves on the recording medium, the resistance of the MR element 11 is changed by the magnetic flux from the magnetic recording recorded on the recording medium, and a voltage change is caused at both ends of the reproducing circuit 16. Is processed and outputs a reproduction signal.

According to the first embodiment described above, the MR head 1
Since 5 is integrated with the fixed resistor 12, the configuration on the reproducing circuit side is simplified, electromagnetic noise can be suppressed, and cost can be reduced.

3A and 3B are views showing a second embodiment of the present invention. FIG. 3A is a front view of a main part, and FIG. 3B is a sectional view taken along line bb of FIG. This embodiment is the same as the previous embodiment in that the fixed resistor 12 for the reproducing circuit is provided in a part of the lead conductor 13 of the MR element 11 to configure the MR head, and the main point of this embodiment is this MR head. Electromagnetic shield 1
That was the shield at 7. The electromagnetic shield 17 may be a shield body known as an upper shield or a lower shield in this type of MR head, or a magnetic pole of an inductive head for writing in a composite head.

The present embodiment thus constructed has the same functions and effects as the previous embodiment, and since it can be electromagnetically protected by the magnetic shield, it is small in size and high in noise resistance. The head is obtained.

4A and 4B are views showing a third embodiment of the present invention, FIG. 4A is a front view of a main part, and FIG. 4B is a circuit diagram shown together with a reproducing circuit. In this embodiment, the MR head is provided inside the electromagnetic shield 17, and the MR head is provided with the fixed resistor 12 for the reproducing circuit in a part of the lead conductor 13 of the MR element 11, as in the previous embodiment. The point of this embodiment is that the capacitor 14 for blocking the DC component is provided on the way to the reproducing terminal of the lead conductor 13 from the MR element 11. The formation of this capacitor 14 is described in Japanese Patent Laid-Open No.
Dielectric material 18 as described in No. 40919.
Can be sandwiched between the lead conductors 13.

In this embodiment thus constructed, the capacitor 14 for blocking the direct current component is also electromagnetically shielded,
The size is further reduced as compared with the previous embodiment, and the noise resistance is also improved.

FIG. 5 is a diagram showing a fourth embodiment of the present invention. In the figure, 21 is a sense region of the MR element part, 2
Reference numeral 2 is a fixed resistance region of the MR element portion, 23 is a lead conductor to the reproducing terminal, and 24 is a lead conductor to the sense current terminal. Usually, in the MR element, the length L of the MR element pattern is formed to be about 150 μm in order to stabilize the magnetic domain in the sense region. In this embodiment, a portion which is not actually used for signal sensing is used as a fixed resistor.

In this embodiment thus constructed, the structure is simplified and the sense current flows through the entire element,
It also contributes to the stability of magnetic domains in the sense region.

[0022]

According to the present invention, the reproducing circuit of the MR head is simplified, and a reproduced signal of high quality can be obtained without electromagnetic noise from the outside being mixed from the reproducing circuit.

[Brief description of drawings]

1A and 1B are views showing a first embodiment of the present invention, in which FIG. 1A is a front view of a main part, and FIG. 1B is a circuit diagram shown together with a reproducing circuit.

FIG. 2 is a diagram showing a manufacturing process of the first embodiment of the present invention.

3A and 3B are views showing a second embodiment of the present invention, in which FIG. 3A is a front view of a main part, and FIG. 3B is a sectional view taken along line bb of FIG. 3A.

FIG. 4 is a diagram showing a third embodiment of the present invention, (a) is a front view of a main part, and (b) is a circuit diagram shown together with a reproducing circuit.

FIG. 5 is a diagram showing a fourth embodiment of the present invention.

FIG. 6 is a diagram showing a conventional MR head and a reproducing circuit.

[Explanation of symbols]

 11 ... MR element 12 ... Fixed resistance 13, 23, 24 ... Lead conductor 14 ... Capacitor 15 ... MR head 16 ... Reproducing circuit 17 ... Electromagnetic shield 18 ... Dielectric 21 ... Sense area 22 ... Fixed resistance area

Claims (3)

[Claims] 1. In a magnetoresistive effect magnetic head having a magnetoresistive effect element (11), a fixed resistor (12) defining a sense current amount supplied from a constant voltage circuit is pulled out from the magnetoresistive effect element (11). A magnetoresistive effect magnetic head characterized by being provided in the middle of a conductor (13). 2. A magnetoresistive effect type magnetic head having a magnetoresistive effect element (11), wherein a fixed resistor (12) for regulating the amount of sense current supplied from a constant voltage circuit and a DC blocking capacitor (14) for a reproducing circuit. ) Is provided in the middle of the lead conductor (13) of the magnetoresistive effect element (11). 3. The magnetoresistive effect magnetic head according to claim 1, wherein the fixed resistor (12) utilizes a part of a magnetoresistive effect element pattern.