JPH0330103A - Magnetic head - Google Patents

Abstract

PURPOSE:To increase a linear recording density even if a high magnetic permea bility material is not used by setting a writing head in such a manner that the longitudinal direction of a head gap is in the transverse direction of tracks and forming the shape of the tape sliding surface to the shape having the curved surface smooth to the tape. CONSTITUTION:A ferromagnetic substrate 2 is worked to constitute a closed magnetic circuit and a coil 1 is wound around a part thereof to generate a writing magnetic field. The magnetic gap 3 for leaking the writing magnetic field is formed near a tape sliding surface 11 by using a nonmagnetic material. A magnetic tape 4 which is a medium slides in the tape traveling direction of an arrow dt with respect to the magnetic head. The sliding surface 11 is worked to the shape having a suitable curve in the tape sliding direction dt for this purpose. The longitudinal direction of the magnetic gap 3 constituted of the magnetic head and the magnetic yoke of the yoke type head for reproduc tion is set in the track direction in such manner, by which the high-density magnetic recording and reproducing at the relatively large gap length are ena bled even with the head material having a low saturation magnetic flux density and a low coercive force medium material.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to magnetic recording technology, and particularly to a magnetic head that records at a high track density and reproduces efficiently.

In fields such as VTRs and computer external storage devices that utilize direct magnetic recording technology, higher performance magnetic heads and magnetic recording media are required to improve magnetic recording density. There is a demand for higher density in both linear recording density and track density. In addition, in order to narrow the magnetization transition region on the medium, we have developed media materials with high coercive force, precision processing technology to narrow the head track to increase track density, and even in narrow track magnetic cores, we have developed technologies for electromagnetic induction. There is a need for materials with high magnetic permeability that can introduce sufficient magnetic flux.

However, at present, even in the prototype stage, magnetic heads with track widths of several micrometers have been announced.
Recording density comparable to that of optical recording has not yet been achieved. The conventionally used magnetic head is shown in Fig. 8(a).
, as shown in FIG. 9, the gap length direction d8 of the head and the track direction dt were set to be the same, and recording and reproduction were performed. The magnetization distribution within the medium according to the conventional recording method is
As shown in Figure 1O, the shorter the recording bit, the greater the self-demagnetization, making it difficult to perform sufficient recording, and higher performance recording heads and media have been required. (Reference: High-density magnetic recording technology collection: O-force general technology center) In Figures 8 and 9, 1 is a coil formed by winding copper wire, etc., and 2 is a ferromagnetic material such as ferrite. The magnetic core 3 formed by S is a magnetic gap provided in the magnetic core 2.
I.O. and A I 20. Alternatively, it can be made by filling the core void with glass. In general, 4 is a magnetic tape which is a recording medium, 5 is a signal magnetization formed on the magnetic tape, and 6 is a protection plate which is also a non-magnetic substrate.

By the way, in conventional magnetic heads, head track processing to increase track density is more difficult as the track density increases, and it is also necessary to use a high magnetic permeability material as the head material. In addition, in order to increase the linear recording density, a high saturation magnetic flux density was required for the head material, and a high coercive force material was required for the medium material.

+1'l L = 2-The magnetic head of the present invention is as shown in FIG.
As shown in a), the head gap length direction is set to be the track width direction, and the tape sliding surface shape is a smooth surface when viewed in cross section of the tape as shown in FIG. 1(b). Shape with . Regarding the playback head, see Figure 2 (
As shown in a), similar to the recording head described above, this is performed using an MR head having a magnetic yoke set such that the head gap length direction is in the track width direction.

Providing magnetic shields 9 on both sides of the magnetic yoke as shown in FIG. 3(a) is effective for reducing wave interference from adjacent bits.

According to the above configuration, the gap length of the magnetic head corresponds to the recording track width, so even if the gap length is larger than that of the conventional magnetic head, it is possible to realize a track width that is sufficiently smaller than that of the conventional magnetic head. In the reproducing head, the magnetization distribution on the medium caused by the recording head is different from the magnetization distribution caused by the conventional recording head, and is not concentrated in the magnetization transition region as shown in FIG. 7(b). However, if an MR head is used as a reproducing head, since it is a magnetic flux responsive type, a high reproduction output can be obtained regardless of the state of magnetization distribution. Further, FIG. 5 schematically represents the process of writing onto a medium by the write head in the present invention. As can be seen from this figure, the track width is determined by the gap length.

Regarding the reproducing head, waveform interference components incident from adjacent bits in a track can be effectively reduced by providing magnetic shields made of a high magnetic permeability material on both sides of the yoke.

Another blood prisoner This invention will be explained below with reference to the drawings.

FIG. 1 and FIG. 2 are perspective views showing the structure of a recording head and a reproducing MR head according to an embodiment of the present invention, and the relationship with signal magnetization recorded on a recording medium.

Note that insulating layers and the like are omitted in these figures.

First, as shown in FIG. 1(a), the structure of the recording head of the present invention is basically the same as the structure of the conventional recording head shown in FIG. 8(a), and the manufacturing process is also similar. It is. That is, a ferromagnetic substrate 2 made of ferrite or the like is processed to form a closed magnetic circuit, and a part of the circuit is coated with an insulator in order to generate a write magnetic field. A coil 1 made of Cu or the like is wound around it.

Near the tape sliding surface, a magnetic gap 3 is formed using a non-magnetic material to leak the write magnetic field onto the tape.
3. It is formed using sto2, glass, etc.

In the magnetic head of the present invention, a magnetic tape as a medium slides in the tape running direction indicated by an arrow dt in FIG. 1(a). For this reason, the shape of the sliding member is processed so that it has an appropriate Im surface in the tape sliding direction.

? The +R structure of the reproduction MR head of the present invention shown in FIG.
7 is a magnetoresistive element, and 8 is a magnetic yoke for guiding a signal magnetic field on the tape to the magnetoresistive element 7. The shape of the sliding surface including the music board is similar to that of the recording head when observed from the viewpoint A direction, as shown in FIG. 2(a).

FIG. 4 is an explanatory diagram of the manufacturing process of the reproducing head of the present invention. First, in FIG. 4(a), permalloy (N1-F
E-based alloy) etc. are formed using vapor deposition, sputtering, photolithography, dry etching techniques, etc. Here, 7■ is a lead for supplying current to the MR element.

When applying a magnetic bias to the MR element for the purpose of making the output of the MR element linear with respect to the signal magnetic field, a shunt bias method or the like can be used. When using the shunt bias method, titanium oxide, titanium nitrogen, or the like is formed as a shunt layer on the substrate 91 before the MR material is deposited, and is etched all at once when patterning the MR element shape by etching. Just do it. Next, in order to maintain electrical insulation with the magnetic yoke, a
1 203, S 102 , an insulating film such as glass is formed, and then a magnetic yoke material such as Par 1 Roy, Sendust, amorphous, etc. is used to pattern an MR element. A yoke 8 is formed.

After this, for the lead extraction contact, lead 7
, the upper insulating material is removed, and then a substrate 91 made of the same material as the lower prefectural board is bonded using an adhesive or the like. Finally, 11
The surface is machined as shown in Fig. 3(b) so that it slides well with the tape. At this time, the magnetic yoke 8 is exposed on the sliding surface.

The process of writing onto a magnetic tape using the magnetic head of the present invention is as follows:
As shown in Figure 5.

Recording begins in FIG. 5(a), and initially a downward magnetic field is generated from above, and the medium is also magnetized in that direction. If the magnetic field generated by the head is reversed from bottom to top when the tape advances to the state shown in FIG. 5(b), writing of recording bits with magnetization from top to bottom is completed at that point. If the same process is repeated thereafter, recording bits can be written from the bottom upward as shown in the states shown in FIGS. 5(b) to 5(0). The reproduction process is as shown in Figure 6, but this is a diagram of the principle; in reality, the magnetic field on the tape is converted into MR by a magnetic yoke.
Guided by elements. Basically, it functions in the same way as a conventional MR head. In FIG. 6(a), the MR element is not affected by the tape magnetic field and the magnetization within the MR element does not move, so there is no output. In FIG. 6(b), when the MR element comes over the magnetized signal bit on the tape, the magnetization within the MR element tilts in response to the signal magnetic field caused by the magnetization, and an output is produced by the change in magnetization. The same applies to the case of FIG. 6(C). However, since the direction of magnetization on the tape is reversed, the output also has an opposite sign to that in the case of FIG. 6(b). (For this purpose, in the state shown in FIG. 6(a), a magnetic bias must be applied in advance so that the magnetization in the MR has an inclination of 45 degrees with respect to the stripe direction.) On the recording medium according to the present invention The magnetization pattern is as shown in FIGS. 7(a) and 7(b).

FIG. 10 shows a magnetization pattern on a medium related to conventional recording.

In the conventional example shown in Figure 1O, the magnetic fields generated by adjacent recording bits work to weaken each other's magnetization.
Moreover, the magnetization pattern on the medium according to the present invention becomes more pronounced as the recording wavelength becomes shorter, whereas the magnetic fields generated by adjacent bits mutually form a closed loop, as shown in FIG. It works to strengthen each other's magnetization. That is, the magnetization pattern on the medium of the head according to the present invention is more stable than the conventional one, and from this point of view as well, it is possible to use a material with a relatively low coercive force as the medium material.

Real Blood Section 44 FIG. 3(a) shows a second embodiment of the reproducing head of the present invention. This embodiment is the same as the first embodiment except that a magnetic substrate is used instead of the non-magnetic substrate of the first embodiment, so the same parts are designated by the same reference numerals. The explanation will be omitted. In this embodiment, the reproduction MR
Is the head magnetic? Magnetic substrates 9 are placed on both sides of the disk for the purpose of magnetic shielding. Between the magnetic yoke 8, A1■03, SIO. , a nonmagnetic layer 10 made of glass or the like is disposed. In this embodiment, since the magnetic yoke is magnetically shielded, there is an advantage that waveform interference due to recording magnetic fields of adjacent bits on the magnetic tape can be significantly reduced.

As explained above, the present invention can achieve a relatively large gap length by setting the length direction of the magnetic gap formed by the magnetic head and the magnetic yoke of the reproducing yoke type head in the track direction. Furthermore, high-density magnetic recording and reproducing is possible even with head materials having lower saturation magnetic flux densities and lower coercive force media materials than in the past. For example, if a magnetic head with a magnetic gap length of about 11 is used to perform recording with a recording waveform of about 0.3 μm as in the past, 1 μm×0.3
Writing for one wavelength is possible in a μm region.

Note that the above numerical values are for a recording wavelength of 0.3 μm and a recording wavelength of 1 μm.
May be replaced with m. In the recording head, as a processing step for defining the track width, there is no need to use precision processing techniques as in conventional magnetic heads, and the track width can be easily controlled using film forming techniques such as vapor deposition and sputtering.

[Brief explanation of drawings]

FIG. 1(a) shows a recording head according to an embodiment of the present invention;
FIG. 3 is a perspective view showing a schematic pattern of signal magnetization on a magnetic tape by the recording head. (However, the protective plate, etc. is omitted.) Figure 1(b) shows the protective plate near the magnetic tape sliding body when the recording head in Figure 1(a) is observed from viewpoint A. A cross-sectional view including FIG. 2(a) is a perspective view showing the relative relationship between the reproducing MR head of the present invention and recording bits when reproducing a signal written on a magnetic tape by a recording head. (However, the protective plate and the like are omitted.) FIG. 2(b) is a sectional view including the protective plate near the tape sliding surface when observed from the viewpoint A direction. FIG. 3(a) is a perspective view of a reproducing MR head showing another embodiment of the present invention, in which magnetic substrates 9 are arranged on both sides of the reproducing MR head in a narrow manner. Figure 3(b) shows the reproduced MR near the magnetic tape sliding surface when observed from the viewpoint A direction.
A cross-sectional view of the head. FIG. 4 is a perspective view for explaining the manufacturing process of the reproduction MR head according to the present invention. Figure 4(a)
In the figure, an MR element is formed on a substrate and an insulating layer is formed. (b) shows the magnetic yoke formed and the insulating layer on the lead terminals removed. In (e), a protection plate or a magnetic shielding substrate is bonded, and the sliding surface with the magnetic tape is
■The surface has been processed and the lead terminal has been joined to the lead terminal. Figure 5 (a), (b). (c) is a conceptual diagram schematically showing how signals are recorded on a magnetic tape by the recording head according to the present invention. Figure 6 shows
FIG. 2 is a diagram schematically showing the principle of how a read head according to the present invention reproduces a signal on a medium recorded by a recording head according to the present invention. FIG. 7 is a diagram schematically showing the state of signal magnetization formed on a magnetic tape by the recording head according to the present invention. FIG. 8(a) shows a conventional recording head and its recording head. FIG. 2 is a perspective view showing a schematic pattern of signal magnetization on a magnetic tape due to a magnetic tape. (However, the protective plate and the like are omitted.) FIG. 8(b) is a sectional view including the protective plate near the tape sliding surface when observed from the viewpoint A direction. FIG. 8(e) is from the viewpoint B direction.
A cross-sectional view including a magnetic gap portion when observed. FIG. 9 is a perspective view schematically showing a conventional reproduction MR head using a magnetic yoke and a conventional recording head reproducing signal magnetization recorded on a magnetic tape. Figure 10 is a schematic cross-sectional view of the state of signal magnetization recorded on a magnetic tape by a conventional recording head, when observed from a cross section in the tape running direction. When the recording wavelength is long, FIG. 10(b) shows the case where the recording wavelength is relatively short. 1... Coil, 2... Magnetic core, 3... Magnetic gap, S10■, A! 203, glass, etc., 4...magnetic tape, 5...signal magnetization on magnetic tape, ? ...Safety advisory board? ...-MR element, permalloy (N1-Fe alloy),
71... MR element energizing lead terminal portion, 7. ...M
R element energization drawer lead, 8...Magnetic yoke, permalloy, sendust, amorphous, etc., 9.゛{9m&', 斐绝绝绝一, +vF, Ufi■car, 10...Adhesive layer, adhesive , l1...Tape sliding surface of the magnetic head, l3...Thing that acts to strengthen signal magnetization by magnetic lines of force for adjacent bits, l4...Magnetization direction within the MR element. Sukyochi Hizuki Riyu, raw MR'\t's *'3k page 5 Figure j (I. 7 Figure 7, Teiji man {q Heroban also money bill (; Yoroq Night Tee 7゜ Uchimimori Ishi 9 Shakuei 5 Figure 6, t-Yakuro...ALro-4 Seiichi, Tsu YO rehokomi L ga Lα] 4 4 Fig. 9

Claims (1)

Claims: 1. A magnetic head characterized in that the gap length direction of the magnetic head is set in the track width direction on the medium, and the head-tape sliding surface shape is formed into a curved surface in the track direction. 2. Regarding a composite head that reads a signal magnetic field on a medium recorded by the recording head described in claim 1, the recording head described in claim 1 and recording on a tape A magnetoresistive head characterized by having a magnetic yoke constituting a gap whose relative position with respect to the track is in the same direction.