JPH0785427A - Magnetoresistance effect magnetic head - Google Patents

Abstract

PURPOSE:To improve the reliability of an MR head, reduce thermal noises and prevent the generation of Barkhausen noises by regulating the distance between the contact boundary of an antiferromagnetic film and an MR film and the contact boundary of a lead layer and the MR film in the direction of a sense current in a predetermined range. CONSTITUTION:An MR head is generally in the same constitution as a conventional one. When is particularly different from the conventional one is that the distance (d) in the direction of a sense current between the contact boundary 50 of an antiferromagnetic film 8 and an MR film 7 and the contact boundary 51 of a lead layer 9 and the MR layer 7 is regulated to be 1.5 to 4mum. At this time, even when a track width is narrowed to not larger than 5mum to achieve a high density, the MR head shows an electric resistance as represented by a theoretical value and to deterioration of sensitivity without Barkhausen noises.

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 (hereinafter abbreviated as MR head) used in a magnetic recording device such as a magnetic disk device.

[0002]

2. Description of the Related Art There is a remarkable demand for miniaturization and large capacity in the magnetic recording field. For example, looking at a magnetic disk device, the disk diameter is decreasing from 3.5 inches to 2.5 inches, 1.8 inches,
The capacity of one magnetic disk is also said to be 2.5 inches and 150 megabytes.

In order to meet these demands, a metal thin film disk having characteristics of high coercive force, high residual magnetic flux density and low noise has been developed as a magnetic disk. As a magnetic head, a metal in-gap head, a thin film head, and a metal magnetic film are used. Laminated laminated magnetic heads have been developed.

However, all of these magnetic heads utilize the phenomenon of electromagnetic induction, and the reproduction output thereof is proportional to the relative speed between the magnetic head and the magnetic disk. Therefore, when the diameter of the magnetic disk is further reduced, it is no longer possible to obtain a sufficient reproduction output. Therefore, a magnetoresistive effect type magnetic head (hereinafter referred to as an MR head), which senses the magnetic flux from the magnetic disk by utilizing the magnetoresistive effect, is currently proposed.

Here, FIG. 8 shows a conventional MR head.
It is a side view. 1 in the figure is Al₂O₃, TiC, etc.
Substrate composed of black material, 2 is Al₂O₃, SiO₂etc
Insulating layer composed of 3 is soft magnetic material such as NiFe
Lower shield layer composed of 4 and Al₂O₃, SiO
₂Insulation that is made of insulating material such as
The layer 7 is made of a material exhibiting a magnetoresistive effect phenomenon such as NiFe.
The formed magnetoresistive film (hereinafter abbreviated as MR film),
Composed of soft magnetic material such as morphus alloy, NiFe
Soft magnetism for applying a lateral bias magnetic field to the MR film 7.
Film, 6 is Ta, Ti, SiO₂And the soft magnetic film 5
An intermediate layer that magnetically separates from the MR film 7, 8 is FeMn-based
Antiferromagnet for controlling magnetic domain of MR film 7 made of alloy or the like
The conductive film 9 is made of a conductive material such as Au or W.
Lead layer, 10 is Al₂O₃, SiO ₂Insulation material such as
Insulating layer 11, which is composed of
An upper shield layer made of a soft magnetic material such as NiFe, 12
Is Al₂O₃, SiO₂M which is a reproducing head consisting of
An insulating layer for separating the R head and the recording head, 13 is Ni
Lower core layer of a recording head composed of a soft magnetic layer such as Fe, 1
4 is Al₂O₃, SiO₂And recording gap
Is an insulating layer, and 15 is a recording layer made of a soft magnetic layer such as NiFe.
Upper core layer of the pad, 16 is Al₂O₃Consists of etc.
An insulating layer that serves as a protective layer.

In this head, since the recording track width and the reproducing track width can be set individually, wide write-narrow read (wide recording and narrow reproducing) is possible. Further, as a lateral bias method for maintaining the linearity of the output, SAL (Soft-Adjacent) is used.
-Layer) bias method is used, the soft magnetic film 5 is magnetized by a magnetic field generated by a sense current flowing through the MR film 7, and a bias magnetic field is applied to the MR film 7 by a magnetic field generated by the magnetization of the soft magnetic film 5. Is applied. The antiferromagnetic film 8 is for controlling the magnetic domains of the MR film 7 in order to suppress Barkhausen noise peculiar to the MR head, and the exchange coupling magnetic field working with the MR film 7 causes the magnetic field in the track width direction ( (Indicated by an arrow in the figure), a suppressing magnetic field is applied to make the MR film 7 into a single magnetic domain.

The operation of the MR head having such a configuration will be briefly described. When the magnetic field generated by the magnetization recorded on the magnetic recording medium by the recording head flows into the track portion of the MR film 7, the electric resistance changes depending on the magnitude of the magnetic flux.
At this time, since the sense current is flowing through the MR film 7, the change in electric resistance can be detected as a voltage change.

At this time, by changing the thickness of the soft magnetic film 5 and the magnitude of the saturation magnetic flux density, the magnitude of the bias magnetic field is changed to provide the optimum bias.

Further, such a structure in which the width between the antiferromagnetic films 8 is wider than the width between the lead layers has already been disclosed in JP-A-62-40.
No. 610 publication.

[0010]

However, in the above-mentioned conventional example, no mention is made of the difference between the width between the antiferromagnetic films and the width between the lead layers.

At present, as described above, the gap between the lead layers becomes narrower as the recording density is improved. That is, the track width is becoming narrower. At this time, the fact that the difference between the width between the antiferromagnetic films and the width between the lead layers becomes small indicates that the distance between the antiferromagnetic films becomes narrow. When the distance between the antiferromagnetic films becomes narrow, the effect of the exchange coupling magnetic field generated at the interface with the MR film on the track portion becomes strong, and there is a problem that the sensitivity of the MR film decreases. Further, since the portion where the lead layer is in direct contact with the MR film is narrowed, the electrical resistance between the MR elements including the lead layer increases, and thermal noise depending on this electrical resistance increases, so the SN ratio decreases. However, there is a problem that heat generation due to electric current increases.

On the contrary, if the distance between the antiferromagnetic films is too wide as compared with the distance between the lead layers, the electric resistance becomes a value according to the theoretical value, but the effect of the exchange coupling magnetic field disappears and the effect of suppressing Barkhausen noise is reduced. However, there was a problem that

Therefore, the present invention solves the above-mentioned problems, and
It is an object of the present invention to provide a high-performance MR head that uses an Mn-based alloy to reduce the electric resistance, does not lower sensitivity, and does not generate Barkhausen noise.

[0014]

In order to achieve the above object, a magnetoresistive effect element provided on a substrate and an antiferromagnetic film and a lead layer connected to the magnetoresistive effect element are provided,
The contact boundary between the tip of the antiferromagnetic film and the magnetoresistive effect element and the contact boundary between the tip of the lead layer and the magnetoresistive thin-film magnetic head effect element are set at intervals of 1. It was composed of 5 μm to 4 μm.

[0015]

According to the present invention, with the above structure, a low electric resistance can be achieved, the reliability of the MR head can be improved, thermal noise can be reduced, and the sensitivity is not deteriorated.
An MR head without Barkhausen noise can be obtained.

[0016]

【Example】

(Embodiment 1) FIG. 1 is a front view showing an MR head in an embodiment of the present invention. In FIG. 1, 1 is a substrate, 2
Is an insulating layer, 3 is a lower shield layer, 4 is an insulating layer, and 7 is MR.
Film, 5 is a soft magnetic film, 6 is an intermediate layer, 8 is an antiferromagnetic film, 9 is a lead layer, 10 is an insulating layer, 11 is an upper shield layer, 12
Is an insulating layer, 13 is a lower core layer, 14 is an insulating layer, 15 is an upper core layer, and 16 is an insulating layer. These have the same configurations as in the conventional example.

FIG. 2 shows an enlarged view of the MR element portion. The present embodiment is different from the conventional example in that the contact boundary 50 of the antiferromagnetic film 8 with the MR film 7 and the MR film 7 of the lead layer 9 are different.
The interval (indicated by d in the figure) along the sense current flowing direction of the contact boundary 51 with is defined to be 1.5 μm to 4 μm.

Here, the width between the lead layers 9 (track width)
MR heads having various values of d and d were prototyped, and the electrical resistance, output, and Barkhausen noise occurrence probability at that time were measured. The output and the probability of Barkhausen noise occurrence were measured using a 2.5-inch magnetic disk, with a peripheral speed of 5.4 m /
s, frequency 6 MHz. As the definition of Barkhausen noise occurrence probability, 32 times of continuous recording and reproduction are performed.
Calculate the average value (X) and standard deviation (σ) of the output at that time
/ X.

FIG. 3 is a graph showing changes in electric resistance with respect to the value of d when the track width is 3 μm and the MR height is 2 μm. When the value of d is 1.5 μm or less, the electric resistance deviates from the theoretical value and increases.

FIG. 4 shows the probability of occurrence of Barkhausen noise with respect to the value of d when the track width is 3 μm. d
When the value of is larger than 4 μm, it is larger than about 3% which is generally considered to be no problem.

FIG. 5 shows the output with respect to the value of d when the track width is changed. When the track width is about 6 μm, the output hardly changes with respect to the value of d, but the track width is 5 μm.
When it becomes m or less, the smaller the value of d, the lower the output.

As in the present invention, the value of d is changed from 1.5 μm to 4
By defining the width to be μm, it is possible to obtain an MR head that has the electric resistance according to the theoretical value, does not decrease in sensitivity, and has no Barkhausen noise even when the track width is narrowed to 5 μm or less and the density is increased. it can.

Au used for the lead layer 9 has a low electric resistance and is suitable for the lead layer 9. However, depending on the film forming conditions, the adhesive force with the MR film 7 may be lost and the electric resistance may increase. Ta, Ti, Cr, Nb as the lead layer 9
A two-layer film in which one of the metals is a base film and Au is used as a main material, or a structure in which Au is sandwiched between the metals
It is preferable to use a layer film.

(Embodiment 2) A second embodiment of the present invention is shown in FIG.
Shown in. The same reference numerals as those shown in FIG. 1 indicate the same functions, and the description thereof will be omitted. In the present invention, the thickness of the MR film 7 below which the antiferromagnetic film 8 is provided is made smaller than the thickness of other portions. FIG. 7 shows the relationship between the thickness of NiFe used as the MR and the exchange coupling magnetic field generated between FeMn and NiFe. Since the exchange coupling magnetic field becomes stronger as the thickness of NiFe becomes thinner, the exchange coupling magnetic field can be made stronger by reducing the thickness of the MR film below the antiferromagnetic film 8 as in this embodiment. Actually, M under the antiferromagnetic film 8
The value of the exchange coupling magnetic field can be controlled by controlling the thickness of the R film.

[0025]

The present invention, which has the above-described structure, is suitable for achieving a high electric density even when the track width is narrowed, achieving a low electric resistance, and not causing a decrease in sensitivity and causing no Barkhausen noise. An MR head can be obtained.

[Brief description of drawings]

FIG. 1 is a front view showing a magnetoresistive effect magnetic head according to a first embodiment of the present invention.

FIG. 2 is an enlarged view of a magnetoresistive effect magnetic head according to (Embodiment 1) of the present invention.

FIG. 3 is a graph showing the relationship between the value of d and electric resistance.

FIG. 4 is a graph showing the relationship between the value of d and the occurrence probability of Barkhausen noise.

FIG. 5 is a graph showing the relationship between the value of d and the output.

FIG. 6 is a front view showing a magnetoresistive effect magnetic head according to a second embodiment of the present invention.

FIG. 7 is a graph showing the relationship between the NiFe film thickness and the exchange coupling magnetic field.

FIG. 8 is a front view showing a conventional magnetoresistive effect magnetic head.

[Explanation of symbols]

 1 Substrate 2,4,10,12,14,16 Insulating Layer 3 Lower Shield Layer 5 Soft Magnetic Film 6 Intermediate Layer 7 Magnetoresistive Effect Film (MR Film) 8 Antiferromagnetic Film 9 Lead Layer 11 Upper Shield Layer 13 Lower Core Layer 15 Upper core layer

Claims (6)

[Claims] 1. A substrate, a magnetoresistive effect element provided on the substrate, an antiferromagnetic film connected to the magnetoresistive effect element, and the magnetoresistive effect provided on the antiferromagnetic film. A lead layer connected to the element film and supplying a sense current to the magnetoresistive effect element, the contact boundary between the magnetoresistive effect element at the tip of the antiferromagnetic film and the magnetoresistance at the tip of the lead layer. Effect type thin film magnetic head A magnetoresistive effect type magnetic head, characterized in that the interval between the contact boundary with the effect element is 1.5 μm to 4 μm along the direction in which the sense current flows. 2. A magnetoresistive effect type magnetic head according to claim 1, wherein a thickness of a portion of the magnetoresistive effect film in contact with the antiferromagnetic film is made thinner than that of other portions. 3. A NiFe alloy is used as the magnetoresistive film, a FeMn-based alloy is used as the antiferromagnetic film, one kind of metal among Ta, Ti, Cr, and Nb is used as the lead layer, and Au is used as the main material. 2. The magnetoresistive head according to claim 1, wherein the used two-layer film or a three-layer film having a structure in which Au is sandwiched by a metal is used. 4. A substrate, a magnetoresistive effect element provided on the substrate, a pair of antiferromagnetic films connected to the magnetoresistive effect element at a first predetermined distance and not in contact with each other, and the pair of antiferromagnetic films. Each of the magnetoresistive elements is provided on the antiferromagnetic film and is connected to the magnetoresistive effect element at a second predetermined interval narrower than the first predetermined interval. And a contact boundary between at least one antiferromagnetic film and the magnetoresistive effect element, and a contact boundary between the magnetoresistive effect element and the lead layer provided on the one antiferromagnetic film. The interval is 1.5 along the sense current flowing direction.
A magnetoresistive effect magnetic head characterized in that the magnetic head has a thickness of from 4 μm to 4 μm. 5. The magnetoresistive effect type magnetic head according to claim 4, wherein the thickness of a portion of the magnetoresistive effect film in contact with the antiferromagnetic film is made smaller than the thickness of other portions. 6. A NiFe alloy is used as a magnetoresistive film, an FeMn alloy is used as an antiferromagnetic film, and one of Ta, Ti, Cr, and Nb is used as a lead layer and a main material is Au. 5. The magnetoresistive head according to claim 4, wherein the used two-layer film or a three-layer film having a structure in which Au is sandwiched by a metal is used.