JPH053644B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a perpendicular magnetic head, and in particular to a perpendicular magnetic head that can improve the recording density characteristics of perpendicular magnetization recording and reproduction as much as possible. .

[Prior Art] Recently, a perpendicular magnetization recording method in which signals are recorded and reproduced by forming residual magnetization in the thickness direction of a magnetic recording medium has been attracting attention, especially since the demagnetizing field decreases as the recording wavelength becomes shorter for signals. It is attracting attention because of its excellent short wavelength characteristics.

FIG. 1 shows an auxiliary magnetic pole excitation type magnetic head and a magnetic recording medium that constitute the basic circuit of this perpendicular magnetization recording method.

As shown in the figure, the perpendicular magnetic recording medium 1 has a horizontally magnetized film 3 (Fe-Ni, etc.) deposited on a magnetic base 2 by a sputtering method, and a perpendicularly magnetized film 4 (Co-Cr) deposited thereon. It is formed by depositing by sputtering method. A magnetic head 5 for exciting this perpendicular magnetic recording medium 1 has a main magnetic pole 6
It consists of a single magnetic pole magnetic head, high magnetic permeability magnetic bodies 7 and 8 joined to both sides of the head, and a winding 9 wound around these joined states. Second
The figure shows the magnetic head 5 viewed from the tip side of the main magnetic pole 6. The main magnetic pole 6 is disposed at the center of the main pole.

FIG. 3 is a graph showing the recording density characteristics of the perpendicular magnetic head constructed as described above, in which digital signals were recorded and reproduced under the following conditions.

Thickness of main pole: Tm = 1.1μm Track width: w = 300μm Number of turns of excitation coil: N = 50 turns Coil inductance: L = 10μH Relative speed between head and recording medium: v = 2m/sec By the way, As shown in FIG. 3, in an area where the recording density is high, a dip point D occurs where the reproduction voltage drops extremely. Bit length at this dip point D
b The following relationship (1) holds between _p,o and the thickness Tm of the main pole 6.

b _p,o = Tm/2n-0.3 (n = 1, 2, 3,...) ...(1) On the other hand, the bit length at the peak point P of the recording density characteristics
b The following relationship exists between _p,o and the thickness Tm of the main magnetic pole 6.
The relationship in equation (2) holds true.

b _p,o = Tm/(2n-1)-0.3 (n = 1, 2, 3,...)...(2) In this way, in the perpendicular magnetization recording method, the recording wavelength is less than or equal to the thickness dimension Tm of the main magnetic pole. It has been revealed that in the short wavelength range of , a high-order reproduction output is produced which gradually attenuates while repeating a dip point D and a peak point P as shown in FIG. That is, even in the perpendicular magnetization recording method, high-density recording that causes dip point D in the reproduced output is not suitable for practical use.

As a technique capable of eliminating the dip point D, there is, for example, a perpendicular magnetic head disclosed in Japanese Patent Laid-Open No. 169913/1983. According to this technology, the main pole is provided with a relatively thick part and a relatively small part, and the peak point P of the relatively thick part and the dip point D of the relatively small thickness part are made to overlap. , the dip point D of the relatively thick part and the peak point P of the relatively small thickness part.
are made to overlap so that dip points do not occur.

[Problems to be Solved by the Invention] However, according to the above technique, although the dip point D can be eliminated, the obtained characteristic curve will not be smooth.

This invention has been made to solve these conventional problems. An object of the present invention is to provide a perpendicular magnetic head that can obtain a smooth characteristic curve.

[Means for Solving the Problems] The perpendicular magnetic head according to claim 1 includes a first main magnetic pole and a high permeability magnetic thin film or a high saturation magnetic flux provided in contact with the first main magnetic pole. a first magnetic head unit including a first magnetic member made of a density magnetic material; a first winding wound around a first main pole and a first magnetic member; 2 main magnetic poles,
A second magnetic member made of a high permeability magnetic thin film or a high saturation magnetic flux density magnetic material provided in contact with the second main pole, and a second winding wound around the second main pole and the second magnetic member. and a second magnetic head unit, the first and second magnetic head units being arranged along the direction of the recording track.

The perpendicular magnetic head according to claim 2 is the perpendicular magnetic head according to claim 1, in which the thickness of the first main pole is at least twice the thickness of the second main pole. ing.

[Function] According to a perpendicular magnetic head having a first main magnetic pole and a second main magnetic pole having different magnetic properties, the peak point of the first main magnetic pole and the dip point of the second main magnetic pole are made to overlap, and the first main magnetic pole is By making the dip point of the magnetic pole and the peak point of the second main magnetic pole overlap, it is possible to prevent a dip point from occurring in the characteristic curve. In the invention described in claim 1, the first main magnetic pole is further wound with the first winding, and the second main magnetic pole is wound with the second winding. This allows the output of each winding to be weighted, resulting in a smooth characteristic curve.

According to the invention described in claim 2,
Since the thickness of the first main magnetic pole is more than twice the thickness of the second main magnetic pole, in addition to the above effect, it is possible to more reliably eliminate the dip point where the reproduction output drops extremely, and in the single wavelength region. The recording density characteristics can be improved.

[Embodiments of the Invention] A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 4 is a perspective view showing an embodiment of the perpendicular magnetic head according to the present invention.

In the figure, 6a and 6b are main magnetic poles, each having a different thickness. Furthermore, magnetic layers 7 and 8 are provided on both side surfaces of the main magnetic poles 6a and 6b, abutting along these sides and holding the main magnetic poles 6a and 6b. Furthermore, on the outer periphery,
A winding 9 for excitation of the main pole is wound.

The thickness dimension of the main magnetic poles 6a, 6b is determined by the relationship between the bit length and the thickness dimension of the main magnetic poles 6a, 6b.
The first dip point of the main magnetic pole 6b is set so as to substantially overlap the first peak point of the main magnetic pole 6b. Therefore, the thickness dimension of the main magnetic pole 6a is Tma, the main magnetic pole 6
Letting the thickness dimension of b be Tmb, the relationship between the respective thickness dimensions can be given by the following equation.

b _p,l =Tma/2×1−0.3 =Tmb/(2×1−1)−0.3=b _p,l ∴Tma=1.7/0.7Tmb=2.45Tmb Main magnetic pole 6a given such a relationship, 6b
The respective recording density characteristics are as shown in the graph shown in FIG. In the figure, the dip points and peak points of the characteristic curve shown by the solid line and the characteristic curve shown by the broken line coincide at the same recording density so as to compensate for each other. Therefore, the dip point of one main magnetic pole is mutually compensated for by the peak point of the other main magnetic pole, and the respective characteristic curves are combined to form an overall characteristic curve, so that there is no point where the reproduction output drops drastically. , it is possible to obtain a characteristic curve (indicated by a thick solid line in the figure) in which the reproduction output smoothly attenuates as the recording density increases. In other words, even if the recording signal has a wavelength shorter than the thickness dimension of the main magnetic poles 6a and 6b, the wavelength of the recording signal is continuously shortened (higher recording density) until the recording density allows a reproduction output within the permissible range. This results in properties that are fully suitable for practical use.

The magnetic layers 7 and 8 are made of a high magnetic permeability magnetic thin film or a high saturation magnetic flux density magnetic material. In the case of a high magnetic permeability magnetic thin film, since the magnetic permeability is high, the output of the reproduction signal can be increased, and it is used exclusively for reproduction. Used as a head.
In addition, in the case of a high saturation magnetic flux density magnetic material, a large recording current can be passed through it, so that recording can be made stronger, and it is used as a recording-only head.

FIGS. 5 and 6 are perspective views showing other embodiments of the present invention, which provide the same effects as the above-described embodiments.

In the one illustrated in FIG.
c, 6d, 6e, and 6f have different thickness dimensions.

In FIG. 6, the magnetic layers 7, 8 in the embodiment of FIG. 4 are divided together with the respective main magnetic poles 6a, 6b, and
One set of divided units each for b, 7b, and 8b
Ua and Ub are configured, and each divided unit Ua,
Windings 9a and 9b are wound for each Ub.

In FIG. 7, the embodiment of FIG.
It is divided in the same way as in the embodiment shown in the figure, and the dividing unit Uc,
Ud, Ue, Uf are formed, and windings 9c,
9d, 9e, and 9f are wound.

In the above embodiment, the main magnetic pole is formed by combining a plurality of magnetic poles with different thickness dimensions, but it is also possible to use a magnetic material whose permeability in the thickness direction changes as shown in Fig. 9. It may be formed by In this case, the vapor deposited film may be formed by changing the composition ratio of the vapor deposition material constituting the main pole when forming the magnetic head, or by continuously changing the vapor deposition temperature.
In this way, it is possible to configure a plurality of main poles having physically different magnetic properties even though they have the same mechanical thickness.

[Effect of the invention] According to the invention described in claim 1,
Since the first main magnetic pole is wound with the first winding, and the second main magnetic pole is wound with the second winding, it is possible to give weight to the output of each winding, and the output is smooth with no dip points. A characteristic curve is obtained.

Furthermore, according to the invention set forth in claim 2, in addition to the above effects, dip points can be more reliably eliminated, and recording density characteristics in a single wavelength region can be improved.

[Brief explanation of the drawing]

Fig. 1 is a side view showing a magnetic head and magnetic recording medium in a conventional perpendicular magnetization recording method, Fig. 2 is a plan view of the magnetic head in Fig. 1, and Fig. 3 is a recording density in a conventional perpendicular magnetization recording method. 4 is a perspective view showing one embodiment of the perpendicular magnetic head according to the present invention, and FIGS. 5 to 7 each show other embodiments of the perpendicular magnetic head according to the present invention. A perspective view, FIG. 8 is a graph showing the recording density characteristics of the perpendicular magnetic head according to the present invention, and FIG. 9 is an example of a situation in which the permeability characteristics in the thickness direction change in the perpendicular magnetic head according to the present invention. It is a graph diagram showing an example. In the figure, 6a, 6b, ..., 6f are main magnetic poles, 7,
7a, 7b,..., 7f and 8, 8a, 8b,
..., 8f are high permeability magnetic thin films or high saturation magnetic flux density magnetic materials, 9, 9a, 9b, ..., 9f are windings,
Ua, Ub, ..., Uf are division units.

Claims (1)

[Scope of Claims] 1. A first main magnetic pole, a first magnetic member made of a high permeability magnetic thin film or a high saturation magnetic flux density magnetic material provided in contact with the first main magnetic pole, and the first main magnetic pole. and a first winding wound around the first magnetic member;
a second main magnetic pole having different magnetic properties from the first main magnetic pole; and a high permeability magnetic thin film or a high saturation magnetic flux density magnetic material provided in contact with the second main magnetic pole. a second magnetic head unit including a second magnetic member; and a second winding wound around the second main pole and the second magnetic member; the first and second magnetic head units are capable of recording. A vertical magnetic head located along the direction of the track. 2. The perpendicular magnetic head according to claim 1, wherein the thickness of the first main magnetic pole is at least twice the thickness of the second main magnetic pole.