JPH0426971Y2 - - Google Patents

Description

[Detailed explanation of the idea]

Industrial Application Field This idea is a magnetic flux responsive type magnetoresistive head (hereinafter referred to as "Magneto Resistance Effect Head").
This technology aims to improve the regeneration efficiency of MR heads (abbreviated as MR heads). BACKGROUND TECHNOLOGY An MR head is suitable for a magnetic head that reproduces a signal magnetic field from a recording medium, and as is well known,
Used in electronic devices that apply magnetic recording, such as DATs and computers. This MR head is of a magnetic flux response type, and in principle, as shown in Fig. 4, conductive leads 4 and 5 are connected to both ends 2 and 3 of a ferromagnetic MR element 1, and current is applied. When an external magnetic field Hex is applied in the direction perpendicular to the current I, MR
This is based on the magnetoresistive effect in which the magnetization M in the element 1 rotates by an angle θ, and the electrical resistance of the MR element in the current direction changes accordingly. this
The relationship between the external magnetic field Hex and the specific resistance ρ in the MR head is shown by a characteristic curve 6 as shown in Fig. 5, which is a linear relationship, and the faithful reproduction range is generally limited to the region 7. , bias magnetic field HB is applied to MR element 1, operating point 8 is moved to region 7
It is set within. 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 I. Hex=HS+HB......I In this way, as a method of applying the bias magnetic field HB, for example, P134 to P142 of the publication "High-density magnetic recording technology collection" published on December 20, 1983
There are various methods described in . In other words, these bias methods include a. those that use permanent magnets, b. those that use a magnetic field generated by current, c. those that determine the direction of current and magnetization by a structure, and d. those that use a different shape in the MR magnetic film itself. It is broadly divided into those that introduce directional bias and bias. Therefore, the characteristics of each of these methods are listed in Table 1 below.

[Table] From the above methods and their characteristics, methods c or d are generally being put into practical use. Problems to be Solved by the Invention However, in the method c described above, as shown in FIG. , . . . , the angle between the current I flowing through the MR element 1 and the magnetic flux φ _S from the conductor is set to approximately 45° for bias. Therefore, in method c, 1′, 1 in the immediate vicinity of the sliding surface of the MR stripe
In this case, the electric field distribution becomes non-uniform, and the angle between the current and the magnetic flux cannot be uniformly set to the desired angle originally planned. In addition, in method d, the seventh
As shown in FIG. It induces anisotropy. However, in this case as well, since the MR element 1 is formed on an uneven surface, the domain walls of the magnetic domain of the MR element tend to move, resulting in noise. This invention is based on the above circumstances and aims to provide an MR head that can eliminate the drawbacks of each method. Means to Solve the Problems This invention aims to widen the stripe width of the MR element film by at least several times for the MR head, and to extend the stripe width dimension of the MR element film in parallel at predetermined pitch intervals along the width direction of the MR element film. It is characterized by the addition of a conductive film. That is, this invention is a method that takes advantage of the advantages of method c introduced as a conventional technique and eliminates its disadvantages. Effects In this invention, by widening the stripe width dimension of the MR element film, the demagnetizing field of the MR element film is significantly reduced, as can be concretely expressed in the examples described later. In addition, since the aspect ratio of the MR stripe approaches 1, the induced electromagnetic anisotropy induced by stress is reduced by the element stripe width, which is sufficiently small compared to the element length. This makes it possible to form an anisotropy in any direction at the same time when forming an MR element by vapor deposition, sputtering, etc. Furthermore, in this invention, by placing the conductor parallel to the stripe width direction on the part of the MR element where the signal current flows, the current is uniform throughout the part where the current flows, regardless of whether it is at the end of the MR stripe or not. Electric field distribution can be obtained. Embodiment FIG. 1 is a plan view of essential parts of an MR head showing an embodiment of this invention. First, 20 is a substrate such as glass or sapphire, and 21 is an alloy with a composition ratio (weight%) of Ni-80 and Fe-20, by plating, vapor deposition, sputtering, etc. in a magnetic field in a predetermined direction. This is an MR element formed into a thin rectangular shape.
This MR element 21 has a stripe width dimension W, which is the length in the direction perpendicular to the direction in which the current I flows, is several times wider than that shown in FIG. 4, which shows a conventional MR head. There is specificity. And M.R.
The film thickness dimension t of the element 21 is the line A-A and the line B-B.
As can be seen from FIGS. 2 and 3, which show the state cut along the line, it is almost the same as the conventional one. Next, 2
2, 22, ... are arranged at a predetermined pitch interval p on the MR element 21 from the medium sliding end surface in the stripe width direction.
Then, a thin film of Au, Al, or
It is a conductor such as Cu. Further, 23 and 24 are connected to the conductors _{22 , 22} , . This is the power supply lead. The MR head configured as described above has a uniform magnetization distribution because the demagnetizing field Hd is uniform and suppressed over the entire stripe length through which the current I of the MR element 21 flows for the following reason. That is, in an MR element that is generally configured as a rectangular thin film, if its saturation magnetization is Ms, the film thickness is t, and the length of the film in the signal magnetic field direction (stripe width direction) is W, then the demagnetizing field Hd is expressed as follows. Ru. Hd=4πMs・t/W... Moreover, thin films of Ni-80 and Fe-20 usually have a 4πMs
≒10000Oe, so if the film thickness t is constant,
After all, the demagnetizing field Hd is inversely proportional to the dimension w. Therefore, if the dimension W is expanded to several times that of a normal MR element, the demagnetizing field Hd will decrease to an almost negligible number Oe.
Therefore, the magnetic field M caused by the signal magnetic field Hs is accurately formed over the entire stripe length. Furthermore, in this MR head, the conductors 22, 2
2,... are arranged parallel to the stripe width direction at a pitch interval of p where most of the current I flows in the MR element 21, so the current I is always parallel to the stripe length direction. The magnetization direction of the MR film itself can be set at any angle during film formation, so
The angle θ of the magnetization M can be set to, for example, 45°, and as a result, the specific resistance ρ of the MR element during operation can be set to a certain value or more, that is, it is possible to obtain a sufficient reproduction output. Effects of the invention According to this invention, in the MR element, the influence of the demagnetizing field can be reduced and the reproduction output can be increased as a whole, and the reproduction signal in the high frequency range can be biased sufficiently.
A good reproduced signal with good waveform symmetry can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a magnetoresistive head showing an embodiment of this invention, and FIGS. 2 and 3 are cross-sectional views taken along lines A-A and B-B. be. Fig. 4 is a conceptual diagram of a conventional magnetoresistive head, Fig. 5 is its ρ-H characteristic diagram, and Fig. 6 is a conceptual diagram of a conventional magnetoresistive head.
This figure is a plan view of a conventional magnetoresistive head, and FIGS. 7a and 7b are a plan view and a sectional view of another conventional magnetoresistive head. 21... Magnetoresistive element film, 22... Conductor film, W
... Stripe width dimension.

Claims (1)

[Scope of utility model registration request] The aspect ratio of the magnetoresistive element film is close to 1, and the magnetic anisotropy of the element film is approximately 45° with respect to the media sliding edge line.
At the same time, a conductor film is attached perpendicularly to the sliding end at a predetermined pitch interval over the element surface from the sliding end, and in parallel to each other, and the power supply lead for the element is connected to both ends of the element. 1. A magnetoresistive head, characterized in that the head is connected only to a length corresponding to the conductor film.