JPS62277613A - Magneto-resistance effect head - Google Patents

Abstract

PURPOSE:To prevent defective insulation by directly laminating a shielding layer and bias conductor of either of the shielding layer which makes magnetic shielding and a magnetic head provided with the bias conductor into contact with each other. CONSTITUTION:The bias conductor 13 of an MR head is directly deposited and formed on a magnetic material layer 12 which faces a magnetic material substrate 11 to sandwich respective MR elements 1, 1,.... The bias conductor 13 has about the same film thickness as the film thickness of the magnetic material layer 12, i.e., about 1mum and Au having the electric resistance large than the electric resistance of the magnetic material layer 12 for which a ferromagnetic metallic material such as Ni-Fe alloy is generally assigned is selected for the material of said conductor. Since the MR head directly bonds the magnetic material layer 21 and the bias conductor 13, the magnetic material layer 12 and the bias conductor 13 are formed in tight contact with each other on the zone where the MR elements exist on the surface of a nonmagnetic material film 9 after the embedment and formation of the many MR elements 1, 1,... into the nonmagnetic material film 9 consisting of SiO2, Al2O3, etc. The insulating characteristic of the MR elements is thereby maintained.

Description

[Detailed description of the invention] Detailed description of the invention Industrial applications This invention relates to a magnetoresistive head (Magnet).

The present invention relates to noise reduction technology for the Re5istance IJfect Head (hereinafter abbreviated as MR head).

2. Description of the Related Art MR heads are magnetic heads that reproduce signal magnetic fields from magnetic recording media, and as is well known, they are used in magnetic recording applied electronic equipment such as DATs and computers. This M
Unlike conventional thin-film induction heads, the R head is of a magnetic flux response type, and as shown in Figure 2, it is a ferromagnetic MR head.
When the conductive leads 4 and 5 are connected to both ends 2.3 of the element 1 and energized, and an external magnetic field Hex is applied in a direction perpendicular to the flowing current ■, the magnetization M in the MR element 1 rotates by an angle θ. It is based on the magnetoresistive effect. In other words, the specific resistance ρ detected at both ends of the conductive leads 4 and 5 is determined by the external magnetic field ■
It is a function of the angle θ that changes according to ex, and the following (I)
It is shown in the formula.

ρ(θ)=ρ//cos2θ+ρ±5in2θ=ρ−△
ρ5in2θ □(I) However, ρ// is the specific resistance when there is no rotation of magnetization M (θ=
0) ρ± is the specific resistance when the rotation of magnetization M is at right angles (θ=π/2
) △ρ=ρ//−ρ soil.

The relationship between the external magnetic field Hex and the specific resistance ρ is shown by a characteristic curve 6 as shown in FIG. HB is applied to the MR element 1, and the operating point 8 is set within the region 7. That is, the external magnetic field Hex is expressed not only by the signal magnetic field HS from the magnetic recording medium but also by the following equation (n).

Hex = HS + HB (II)
By the way, since a shield type MR head in which the MR element 1 is sandwiched between high magnetic permeability materials was proposed, it has become possible to greatly contribute to the improvement of magnetic recording density. And shield type M
As the R head, for example, IEICE technical research report MR81-27, published December 15, 1981, No. 1
Some of them are introduced in 90.

The shielded MR head described above generally uses SI, which is a non-magnetic insulator, as the MR element 1, as shown in FIG.
The structure is such that the magnetic substrate 11 and the magnetic layer 12 are sandwiched together with the O□ film 9 interposed therebetween. The problem to be solved by the invention is that the magnetic layer 12 is selected to have a low electrical resistance and also serves as a bias conductor.However, in the above-mentioned shield type MR head, the magnetic layer 1
2 is a magnetic material and a conductor, such as an N1-Fe alloy, which has a high electrical resistance among conductors, and therefore generates considerable heat when energized to apply a bias magnetic field. This had the drawback of generating thermal noise. In order to improve this drawback and apply a sufficient bias magnetic field to the MR element 1 even if the current is reduced, the insulation distance between the magnetic layer 12 and the MR element 1 must be reduced as much as possible, resulting in poor insulation. Furthermore, there was a risk that the MR element 1 would be heated and demagnetized.

Means for Solving the Problems The present invention was proposed to solve the above problems, and is characterized by directly stacking the shield layer and the bias conductor. That is, the present invention specifies a ferromagnetic material as a magnetic material layer that is a shield layer that sandwiches and shields an MR element, and a good conductor as a bias conductor, and also uses a direct laminated structure, that is, extremely close adhesion. This is a technology that attempts to solve the problem of thermal noise.

According to this invention, even if a sufficiently large current is passed through the bias conductor, the magnetic layer serving as the shield layer has a higher electrical resistance than the bias conductor, so the current does not flow and the influence of thermal noise is prevented. Can be done. Further, in this invention, since the shield layer and the bias conductor are bonded in close proximity, it is possible to insulate the MR element from both at a sufficient distance, and also to facilitate manufacturing.

Embodiment FIG. 1 is a sectional view taken along a plane parallel to the recording medium sliding surface of an MR head showing an embodiment of the present invention. The same designations as those in FIG. 4 showing the conventional case refer to the same figure. They will be described by number, and duplicate explanations will be omitted. Reference numeral 13 in this MR head is a bias conductor, which is the gist of the present invention, and is used for each MR element 1, 1.
．． ... are directly deposited on the magnetic layer 12 sandwiching the magnetic substrate 11 facing each other. The bias conductor 13 has a thickness similar to that of the magnetic layer I2, that is, about 1 μm, and is made of a material that has a higher electrical resistance than the magnetic layer 12, which is generally made of a metal ferromagnetic material such as a Ni-Fe alloy. Select Au with a large value.

In the MR head of this embodiment, since the magnetic layer 12 and the bias conductor 13 are directly bonded as described above, a large number of MR head
Element 1, 1. ... is buried in a non-magnetic film 9 made of SiO□, A1203, etc., and then a magnetic layer 12 and a bias conductor 3 are closely formed on the MR element existing band on the surface of the non-magnetic film 9, which facilitates mass production. It also improves sex and is convenient.

Incidentally, in the above embodiment, the bias conductor +3 is laminated on the magnetic material B12, but in this invention, for example, a non-magnetic material 1! It is also possible to make X9 sufficiently thick or to have a composition with good heat insulation, to first form the bias conductor 13 on the non-magnetic film 9, and then to coat the magnetic layer 12 thereon.

Effects of the Invention According to the present invention, since the bias conductor is directly laminated on the magnetic layer, the magnetic layer is not affected by thermal noise, and the magnetic shielding effect can be sufficiently enhanced. The reliability is maintained, mass productivity is sufficiently increased, and reliability is significantly increased.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a magnetoresistive head showing an embodiment of the present invention, FIG. 2 is a conceptual plan view of a general magnetoresistive head, and FIG. 3 is a ρ- The H characteristic curve diagram and FIG. 4 are cross-sectional views of the head. DESCRIPTION OF SYMBOLS 1... Magnetoresistive effect element (MR element), 11... Magnetic material substrate (shield layer), 12... Magnetic material layer (shield layer), 13... Bias conductor.

Claims (1)

[Claims] In a magnetic head that is provided with a bias conductor and a shield layer that sandwiches the magnetoresistive element and magnetically shields the magnetoresistive element, the shield layer and the bias conductor are directly laminated to face the magnetoresistive element. A magnetoresistive head characterized by: