JPS63268174A - Magnetic head - Google Patents

Abstract

PURPOSE:To stably maintain the spacing between a head element and a recording medium by placing a superconductive material on the surface opposite to the recording medium of a slider holding the head element, and floating the head by an extremely short level by the Meissner effect. CONSTITUTION:A magnetic head is composed of a head slider 2 and a head element 3 held by a former 2. On the surface of the slider 2 facing oppositely to the recording medium 1, a superconductive ceramic made of a metallic composite oxide - (La, Ba)CuO3, is disposed. When said ceramic is made in superconductive state by cooling it in a magnetic field, a magnetic field opposite the external magnetic field is generated in the material due to the Meissner effect. With a spacing <=0.1mum, the buoyancy radically increases. So, by cooling the slider 2 with liquid nitrogen to make it into superconductive state, and when assuming the load of the slider 2 as 18g, for instance the spacing can be held at 0.1mum stably.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic head, and particularly to a head slider thereof.

[Conventional technology]

What is the spacing between the magnetic head and magnetic recording medium?

A certain interval is necessary to improve output stability and durability. In order to obtain this desired spacing, the head slider that holds the head element and its A supporting structure was designed.

Conventionally, non-magnetic ferrite has been used as the material for the head slider because it is non-magnetic, has a coefficient of thermal expansion similar to that of the core of the head element, can be processed into interfaces, and has wear resistance. and ceramics were used.

[Problem that the invention seeks to solve]

On the other hand, there has recently been a trend towards high-density recording, and in this case it is particularly necessary to reduce the spacing between the magnetic head and the magnetic recording medium as much as possible. However, conventional magnetic heads use non-magnetic ferrite or ceramics as the head slider.

It has been difficult to stably secure a spacing amount of 0.1 μm or less, which has been an obstacle to high-density recording.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a magnetic head that solves the drawbacks of the prior art and allows fall spacing for a magnetic recording medium.

[Means to solve the problem]

In order to achieve the above-mentioned object, the present invention provides a method in which a superconducting material is disposed at least on the side facing the magnetic recording medium of a head slider that holds a head element consisting of, for example, a core, a ferromagnetic thin film, and an excitation coil. This is a characteristic feature.

[Run 1] When a superconducting material is placed in a weak magnetic field and cooled to a superconducting state, the superconducting material receives a magnetic field in the opposite direction to the external magnetic field due to the Meissner effect based on the perfect diamagnetism of the superconducting material. Generate and surface. Taking advantage of this effect, if a superconducting material is placed at least on the side of the head slider facing the magnetic recording medium, in other words, at a location close to the magnetic recording medium, as described above, the head slider will be moved by the magnetic field of the magnetic recording medium. Can levitate. Note that the polarity of the magnetic field from the magnetic recording medium changes depending on the recording state.

This is because a repulsive magnetic field is always generated due to the Meissner effect.

The head slider can always maintain a flying state regardless of changes in polarity.

The reason why the levitation means that utilizes the Meissner effect is advantageous in ensuring a narrow spacing between the magnetic head and the magnetic recording medium is that the repulsive force (-4 force) due to magnetic force is inversely proportional to the cube of the distance. This is because, in the case of viscosity or collision with air, as in the conventional case, if the spacing is about 0.1 μm or more, it is inversely proportional to the distance, and if it is less than that, it becomes constant and the damper effect is lost. This will be explained in more detail as follows.

FIG. 1 is a characteristic diagram showing the relationship between spacing and buoyancy. Curve A in the figure is a curve showing the buoyancy characteristic due to the repulsive force of magnetic lines of force, and curve B is a curve showing the buoyancy characteristic due to the conventional air resistance force.

As shown in curve B, in the case of buoyancy due to air resistance, when the spacing gradually narrows from 0.3 μm to 0.1 μm, the buoyancy increases rapidly, but when the spacing is 0.
．． When the diameter is less than 1 μm, the buoyancy becomes almost constant and no further increase can be expected.

Therefore, if the load on the magnetic head is increased even slightly in order to narrow the spacing, the force will exceed the buoyancy, and as a result, the magnetic head will come into contact with the magnetic recording medium.
Appropriate spacing cannot be stably secured for high recording density.

On the other hand, when using the repulsive force of magnetic lines of force, as is clear from curve A, a repulsive force (buoyant force) is always generated that is inversely proportional to the cube of the spacing (distance), so especially when the spacing is 0 When the spacing becomes narrower than .1 μm, the buoyancy increases rapidly.

It has the advantage that even if a fairly large load is applied to the magnetic head, a small gap is stably maintained between the magnetic head and the magnetic recording medium.

The superconducting materials used in the present invention include:

For example, there are total bending materials such as Nb-AL-Ge, Nb-N, and Nb-"Ge. Furthermore, superconducting ceramics are used as materials with high critical temperatures. There are complex metal oxides.

general formula %formula% A in the formula is La, Y or a mixture of La and Y.

B is BaISr or a mixture of Ba and Sr.

Or perovskite B a P, bx-xB i XO! (xxo, 3
)a This composite metal oxide has properties intermediate between those of a full metal oxide and a semiconductor.

Embodiment 1 FIG. 2 is a perspective view showing a state in which a magnetic head and a magnetic recording medium face each other according to a first embodiment of the present invention. Diameter is 5.2
Magnetic storage medium consisting of a 5-inch floppy disk
is a substrate 1a made of a polyimide film with a thickness of 50 μm.
and a magnetic recording film 1b formed on the surface of the substrate 1a and made of a 2 μm thick Go-Cr alloy thin film at t=o. The saturation magnetization of this magnetic recording medium l is 3
00 [emu/ca1. The coercive force in the vertical direction is 700 (
Os), and the coercive force in the in-plane direction is 250 (Oa).

On the other hand, the magnetic head mainly consists of a head slider 2 and a head element 3 held by the head slider 2. The head slider 2 contains superconducting ceramics made of a metal composite oxide of (La, Ba)CuO-1. The head element 3 is embedded in a part of the head slider 2 on the side facing the magnetic recording medium 1, and although not shown,
Consisting of a core, a ferromagnetic thin film made of an amorphous alloy with high permeability and high saturation magnetic flux density formed on the side of the core facing the magnetic gap, and an excitation coil wound around the coil window of the core. has been done.

When writing or continuously outputting signals to the magnetic recording medium 1, the head slider 2 can be cooled to a critical temperature with liquid nitrogen to bring the head slider 2 into a superconducting state. By setting the load on the head slider 2 of the magnetic head at this time to xa (g), the spacing between the magnetic recording medium and the magnetic head could be stably maintained at 0.10 μm.

Embodiment 2 FIG. 3 is a perspective view showing a second practical example of the present invention. This embodiment differs from the first embodiment in the configuration of the head slider 2.

That is, the head slider 2 includes a base body 2a made of ceramic such as barium titanate or non-magnetic ferrite, and B a P b o, yBio, not formed on the side of the base body 2a facing the magnetic recording medium l. The point is that it is composed of M2b containing a superconducting material.

In the magnetic head of this embodiment as well, the spacing with respect to the magnetic recording medium 1 is accurately maintained at 0.10 μm or less.

Embodiment 3 FIG. 4 is a perspective view for explaining a third embodiment of the present invention. The magnetic recording medium 4, which is a hard disk with a diameter of 5.25 inches, is made of a substrate 4a made of aluminum with a thickness of 1.92 on, and a 0.000 mm film formed on the surface of its base Fi 4a.
, and a magnetic recording film 4b made of a Co--Ni alloy thin film with a thickness of 0.5 μm. The saturation magnetization of this magnetic recording medium 4 is 1100 emu/eel, and the coercive force in the in-plane direction is 650 [oe].

On the other hand, the magnetic head is composed of a head slider 5 and a head element 6 held by the head slider 5.

The head slider 5 is (L a , B a ) Cu
Contains Oi's superconducting ceramics.

- As shown in the figure, the RAD slider 5 has an outer protrusion 5a and an inner protrusion 5b on the side facing the magnetic recording medium 4.
It has an intermediate protrusion 5C provided therebetween. Grooves 5d for conducting air are formed between the outer protrusion 5d and the intermediate protrusion 5C, and between the inner protrusion 5b and the intermediate protrusion 5C. The head element 6 is embedded and held in the intermediate protrusion 5C, and the intermediate protrusion 5c is shorter than the other protrusions 5a and 5b, and has a floating inclined part 5e at its tip. is formed. Note that the arrow X in FIG. 1 indicates the rotation direction of the magnetic recording medium 4.

The head element 6 includes a core, a ferromagnetic thin film having high magnetic permeability and high saturation magnetic flux density made of an amorphous alloy formed on the side of the core opposite to the magnetic gap, and a ferromagnetic thin film having high magnetic permeability and high saturation magnetic flux density. It consists of an excitation coil wrapped around a coil window.

The load on the head slider 5 of this magnetic head is 10 (g
), the spacing between the magnetic recording medium and the magnetic head could be stably maintained at 0.07 μm.

In each of the above embodiments, a case has been described in which the head element is embedded in the head slider, but the present invention is not limited thereto. It can also be applied to other types of magnetic heads.

Furthermore, in each of the above embodiments, a case has been described in which a head element composed of a core, a ferromagnetic thin film, an excitation coil, etc. is used, but a magnetic head using a thin film head element formed using RrIA technology may also be used. The present invention can be applied.

Further, as a means for cooling the layer made of superconducting material to a critical temperature, it is appropriate to surround the magnetic head and cool it using a cooling medium such as liquid helium or liquid nitrogen.

If ceramics are used as the superconducting material as in the above embodiment, it has advantages such as its relatively high critical temperature, easy cooling, wear resistance, and small difference in thermal expansion from the core. have.

The amount of spacing can be changed by changing the load on the head slider as described above, but it can also be changed appropriately by changing the volume of the superconducting material and controlling the strength of the repulsive magnetic force. It is possible to easily change the amount of spacing, such as small spacing for high recording density and large spacing for low recording density.

[Effects of the Invention] As described above, the present invention is characterized in that a superconducting material is disposed at least on the side facing the magnetic recording medium of the head slider that holds the head element.

By forming such a IIW structure, it is possible to make the superconducting material (L) float a small distance from the magnetic recording medium by utilizing the Meissner effect. Ko〉(-roll can be easily achieved.

[Brief explanation of drawings]

FIG. 1 is a characteristic diagram of buoyancy with respect to spacing, FIG. 2 is a perspective view showing a state in which a magnetic head and a magnetic recording medium face each other according to a first embodiment of the present invention, and FIG. A perspective view showing the facing state of the magnetic head and the magnetic recording medium according to the embodiment, No. 4r! FIG. 1 is a perspective view showing a state in which a magnetic head and a magnetic recording medium face each other according to a third embodiment of the present invention. 1.4... Magnetic recording medium, 2.5...
Head slider, 2a-...Base, 2F)...
...Layer containing superconducting material, 3.6...Head element, 5a...Outer protrusion, 5b...
Inner protrusion, 5c...Intermediate protrusion, 5d...
・Groove, 5e... Slanted part. Figure 1 District 2!

Claims (3)

[Claims] (1) A magnetic head comprising a head slider and a head element held by the head slider, characterized in that a superconducting material is disposed at least on the side of the head slider facing the magnetic recording medium. . (2) A magnetic head according to claim (1), wherein the superconducting material is ceramic. (3) A magnetic head according to claim (1), characterized in that means for drawing in an air flow is provided on the side of the head slider facing the magnetic recording medium.