JPS61129703A - Magnetic information reproducing device - Google Patents

Abstract

PURPOSE:To make possible the reproduction of the magnetic information of a magnetic recording medium with inexpensive magnetic head constitution by reproducing the magnetic information of the magnetic recording medium with the DC magnetic field component of the magnetic recording medium as a bias magnetic field. CONSTITUTION:An MR element 2 is installed to face the recording surface of the magnetic recording medium 1. Both ends thereof are connected to a constant current source 3 and output terminal 6. The DC residual magnetization Mb to apply the suitable bias magnetic field Hb to the element 2 and the residual magnetization ms to generate magnetic information hs are recorded on the medium 1. The operation point of the MR element is brought to the point P by the bias magnetic field Hb generated from the medium 1 and the magnetic information hs is made the change in the specific resistance of the element 2. The reproduced output is reproduced as a signal voltage Vout of the reproduced output by constant current I0.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a magnetic head (MR head 1) composed of a magnetoresistive element (MR element), which reproduces magnetic information recorded on a magnetic recording medium. Regarding a playback device.

[Technical background of the invention and its problems]

When reproducing magnetic information recorded on a magnetic recording medium, a general f-nilling type magnetic head is used, but PCM
When reproducing magnetic information recorded in parallel on multiple tracks (e.g., track C:), a magnetic head with a thin film structure is used in which a plurality of corresponding read head elements are fully integrated.Such a thin film magnetic head An MR head is considered to be promising as a f-requirement.A magnetic information reproducing device using an MR head has an MR head installed facing the recording surface of a magnetic recording medium, and a constant current is generated by applying an appropriate bias magnetic field to the MR head. It reproduces flowing magnetic information.

The term "appropriate bias magnetic field" as used herein generally refers to a direct current magnetic field applied to the CMR head so that magnetic information from a magnetic recording medium can be reproduced with low distortion and high sensitivity.

The DC Ia field given to this MR head node is MR head node ≦
There are two methods: a method of embedding a Nanagi stone to obtain a bias magnetic field, and a current bias method of passing a current through an MR element (two conductors formed close to each other to generate a bias magnetic field).

However, the method of embedding a magnet in the MR head node is based on the base VjL.
≦; It is necessary to go through an extra step of processing the groove in which the magnet is to be embedded, embedding the magnet there, fixing it with a bonding agent, and magnetizing it. For this reason, it is difficult to align the MR head bias magnetic field over the entire tortoise, making it expensive. On the other hand, in the current bias method, a bias magnetic field is generated by an L-turn winding, etc., but considering the generation of heat, the bias magnetic field is not sufficient. There must be. As described above, there are many requirements for a reproducing MR head, and it has been impossible to use an MR head with a simple structure.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic information reproducing apparatus which reproduces magnetic information from a magnetic recording medium with an inexpensive magnetic head configuration, while eliminating the drawbacks of the prior art described above.

[Summary of the invention]

The magnetic information reproducing apparatus according to the present invention is characterized in that a constant current is passed through an MR head installed facing a magnetic recording medium having a DC magnetic field component, and the DC magnetic field component of the magnetic recording medium is used as a bias magnetic field to generate the magnetic field of the magnetic recording medium. It is characterized by reproducing information.

In other words, so that a certain DC magnetic field component remains in the magnetic recording medium (2. When recording magnetic information, a DC magnetic field is superimposed or DC magnetized in advance, and this DC magnetic field component element becomes the optimal bias state for the MR head at the same time. Reproducing magnetic information from the magnetic recording medium.

〔Effect of the invention〕

According to the second aspect of the invention, it is not necessary to take any special measures to obtain an MR head bias magnetic field, and it is possible to provide a magnetic information reproducing apparatus using an MR head which is inexpensive and has good performance.

[Embodiments of the invention]

FIG. 1 shows the configuration of a magnetic information reproducing apparatus according to an embodiment (second embodiment) of the present invention. In the figure, the magnetic recording medium is, for example, a magnetic tape, and the recording surface (magnetic surface) of the magnetic recording medium is ), and the two ends of the MR element 2 are connected to a constant T4 flow source 3 and an output terminal 6C.

The magnetic recording medium l is an MR probe 2 C with an appropriate bias magnetic field H
In order to give b, DC residual magnetization Ml) and magnetic information (
The residual magnetization ms that generates the signal magnetic field ha is recorded. FIG. 2 is an explanatory diagram of the operation of the MR element, and shows the relationship between the specific resistance ρ of the MR element and the applied magnetic field I. Here, the bias magnetic field Hb1 generated from the magnetic recording medium l is expressed as the operation of the MR element. Point t There are methods of superimposing a direct current when recording magnetic information, and methods of making the magnetic head 6Wta in advance (for example, using a DC erase head or the like).

According to the second aspect of the present invention, a magnetic recording medium having an appropriate DC magnetic field component is used. Therefore, there is no need to provide a bias generating means for the MR head, and the head structure is simple (2). A magnetic information reproducing device can be provided.

FIG. 3 shows the method of providing the magnetic recording medium IC of the present invention with a high magnetic force layer 7 (Secondly, stabilizing the bias magnetic field Hb), in which the DC residual magnetization Mb described above is previously magnetized with DC current. This is especially effective when direct current magnetization is performed in the manufacturing process of two-magnetic recording media.

Figure @4 shows a magnetic information reproducing device according to another embodiment of the present invention, in which a current bias line 8 (two constant currents 11 are passed through an MR element 2 (
: At the MR head node 2 of a method that gives a bias magnetic field f (bc), it is combined with @thermal recording medium l having a DC magnetic field component Hb. A suitable bias field can be applied to a medium with small residual magnetization (both MR and quadrupole C).

FIG. 5 shows a reproducing device for a magnetic plate according to another embodiment of the present invention, in which a magnetic layer 4 made of a strong material or the like is provided around a rotating cylinder 9, and this C is properly magnetized and signalized. is detected by the motor's (c!J rotation state) and obtained from the output terminal 6.
Compared to the conventional output waveform S when no bias is applied (2), the output waveform b1 of the present invention has a large sought-after amplitude and is an easy-to-handle signal waveform.Therefore, despite the simple MR element 2, it has good accuracy. Rotation detection and signal processing circuits can be simplified.

This invention is not limited to the above-described embodiment (21/2) and can be modified without departing from the gist of the invention. For example, the number of MR elements is one in the embodiment, but a plurality of It is also possible to use a magnetic recording medium created using a four-layer process (2).Furthermore, although the magnetic recording medium in the embodiment has a single-sided magnetic layer, it may also have a double-sided magnetic layer. Although the explanation was given using a medium, all magnetic recording media such as perpendicular recording media can be used, and regarding the bias magnetic field, 1. Spatial change in magnetization in the head running direction is zero, and it has direct current magnetization. Bye.

[Brief explanation of the drawing]

FIG. 1 is an embodiment of the present invention (a configuration diagram of a magnetic information reproducing apparatus according to the invention, FIG. 2 is a diagram for explaining the operation of the embodiment, and FIGS. 3, 4, and 5 are diagrams of this embodiment. Other embodiments of the invention (
: A sectional view of the magnetic recording medium and a configuration diagram of the magnetic information reproducing apparatus. FIG. 6 is a diagram for explaining the operation of another embodiment. l... Magnetic recording medium 2... Magnetoresistive element 3.
・・Constant power supply s 4・Magnetic layer 5・Base film 6・・Output terminal 7・… - Motor rotation axis. Representative Patent Attorney Kensuke Norichika (and 1 other person) First drawing. Figure 2 Figure 3

Claims (1)

[Claims] In an apparatus for reproducing magnetic information from a recording medium using a magnetic head composed of a magnetic recording medium and a magnetoresistive element placed opposite to the magnetic recording medium, the DC magnetic field component from the magnetic recording medium is used as a bias magnetic field. A magnetic information reproducing device characterized by reproducing magnetic information from a magnetic recording medium.