JPH01178190A - Multiple layer solid-state magnetic memory device - Google Patents

Abstract

PURPOSE:To improve mechanical durability by laminating a solid-state magnetic memory device in plural layers in which the crossing part of first and second strip shape superconductors and the crossing part of a third stripe shape superconductor and a stripe shape magneto-resistance effect device are arranged at positions confronting with each other via a magnetic storage medium layer. CONSTITUTION:On the magnetic storage medium layer 5, plural section stripe shape superconductors 1 keeping prescribed intervals, plural first stripe shape superconductors 2 which cross with the second stripe shape superconductor 1 at a prescribed angle, and plural magneto-resistance effect devices 7 are provided, and furthermore, on the resistance effect devices 7, plural third stripe shape superconductors 8 are provided, respectively. And plural solid-state magnetic memory devices (100-102) in which the crossing part of the first and second superconductors 2 and 1 and the crossing part of the third superconductor 8 and the magneto-resistance effect device 7 are arranged at the positions confronting with each other via the magnetic storage medium layer 5 are laminated. In such a way, the mechanical durability can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a multilayer solid state magnetic memory element used as an external storage device for a computer.

(Prior Art) Conventionally, magnetic disk devices have been the mainstream of external storage devices for computers, but magnetic tape devices and floppy disk devices have also been used.

Recently, optical disk devices and electronic disks using IC memory have also come into use.

(Problems to be Solved by the Invention) Conventional magnetic disk drives have a rotating mechanism, so they have the drawback of long access times and also have problems with mechanical durability of disks and heads. Similarly, optical discs also have the problem of long access times due to their rotating mechanisms and recording and reproducing methods. Furthermore, since electronic disks are non-volatile, there is a problem in that long-term data storage is not possible.

SUMMARY OF THE INVENTION An object of the present invention is to provide a solid-state magnetic memory element that eliminates these drawbacks, does not require a rotating system, and is capable of long-term data storage.

[Means for solving problems]

The structure of the solid-state magnetic memory element of the present invention is such that a plurality of second stripe-shaped superconductors are formed at predetermined intervals on one main surface of a magnetic storage medium layer with an insulating layer interposed therebetween. and a plurality of first striped superconductors intersecting each of the second striped superconductors at a predetermined angle via an insulating layer on the main surface of the magnetic storage medium layer. Conductors are formed at predetermined intervals, and a plurality of striped magnetoresistive elements are formed at predetermined intervals via an insulating layer on the other main surface of the magnetic storage medium layer. A plurality of third striped superconductors are formed at predetermined intervals on the main surface and on the striped magnetoresistive element via an insulating layer, and each of the first and second striped superconductors is A solid-state magnetic memory element is arranged in a position where an intersection part and an intersection part of the third striped superconductor and the striped magnetoresistive element face each other with the magnetic storage medium layer interposed therebetween,
It is characterized by being formed by laminating multiple layers.

[Effect]

According to the configuration of the present invention, it is possible to configure a solid-state memory element that does not require a rotation system and does not pose a problem in mechanical durability. That is, information is recorded on a magnetic medium by a magnetic field caused by a current flowing through a striped superconductor, and information written on the medium is reproduced by a striped magnetoresistive element.
These are formed integrally with the medium. Furthermore, since a magnetic medium is used as the medium, it is possible to store the medium for a long period of time.

〔Example〕

Next, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a schematic perspective view showing an embodiment of the present invention and its peripheral circuit, and FIG. 2 is a schematic perspective view showing a part of this embodiment. In this embodiment, a plurality of solid-state memory elements shown in FIG.
It has a structure in which 121f is joined together. Further, in the peripheral circuit of this multilayer solid-state memory device, for example, data flip-flops 45 of a part of the solid-state memory device are combined into a buffer register 130 and connected to the CPU and the interface 14.

As shown in FIG. 2, one layer of this embodiment has a first striped superconductor 2 and a second striped superconductor 1 that intersect with one main surface of the magnetic recording medium #5. ing. Here, the second superconductor 1 is formed directly on the magnetic recording medium layer. During recording, a current is passed through these two striped superconductors 1.2 to magnetize the magnetic recording medium 5 near their intersection. - On the other main surface of the magnetic recording medium layer 5, intersecting striped magnetoresistive elements 7 and a third striped superconductor 8 are formed.

Here, the magnetic recording medium layer 5 is formed directly on the striped magnetoresistive element 7. During reproduction, a sense current is passed through the third striped superconductor 8, and the stored magnetization information is extracted as a resistance change of the striped magnetoresistive element 7.

Next, an example of the configuration of the memory circuit during recording will be explained using FIG. 2. The first striped superconductor 2 and the second striped superconductor 1 each have a first switch group 20
．． 21.22.23.24°25 and 26.27.28
．． It is connected to 29.

Switches 26, 27, 28, 29 each have a current source 30
．． 31 and the first Y-axis address 7” Korg 1
It is connected to 9. Switch 20°21.22,23.
24.25 connects to the current source on one side and data “1” on the other side.
47, 48, 49,
50,51.

52 to the first X-axis address decoder.

Also, and gate 47.48, 49.50°51.5
2 is connected to the CP via the data flip-flop 45.
The first X-axis address decoder 44 is connected to the CPU and the interface 14 through the first X-axis address register 46, and the first Y-axis address decoder 19 is connected to the CPU and the interface 14 through the first Y-axis address register. It is connected to the interface 14.

Next, an example of the structure of the memory circuit during reproduction will be explained using FIG. 4. During reproduction, the striped magnetoresistive element 7 and the third striped superconductor 8 formed on the magnetic storage medium layer 5 are used. The third striped superconductor 8 is connected to a current source 33 via a switch 32.34. Switches 32 and 34 set the second Y-axis address;
CP data via the second Y-axis address register 36.
It is connected to U and interface 14. On the other hand, the striped magnetoresistive element 7 has switches 38°, 39.
These switches 38, 39, and 40 are connected to the CPU and interface 14 through the regeneration circuit system 43.
At the same time, it is connected to the CPU and interface 14 via a second X-axis address decoder 41 and a second X-axis address register 42.

Next, the operation during data recording of this embodiment will be explained with reference to FIGS. 5 and 6.

Figure 5 (, 0 is a perspective view of the case where there is a superconductor 1.2 perpendicular to the ferrite magnetic storage medium s, and Figure 5 ( , 0 is a perspective view of the case where there is a superconductor 1.2 perpendicular to the ferrite magnetic storage medium s. Shown below.

In FIG. 5 (!ll), the first X-axis address register 46, first X-axis address decoder 44, and data flip-flop 45 are set by instructions from the CPU and interface 14 in FIG. switch group 2
0, 21. 22, 23, 24° 25 and the first X-axis heavy flow source 16.17 and the AND gate 47, 48. 49, 50, 5
1. Select one from 52, turn it on, and turn it on to the first (X-axis)
A current Ix (pulse or direct current) is passed through the striped superconductor 2, and the current Ix is
magnetic field (magnetic field Hx smaller than Hc of the magnetic recording medium)
is recorded on the magnetic recording medium 5. However, in this state, data is not transferred to the magnetic recording medium. Next, when a current y is applied to the second striped superconductor 1 perpendicular to each other, a current Iy is applied as shown in FIG. 45 for each applied magnetic field Hx and Hy.
It has an angle of degrees.

ζHere, the magnetic field H due to the current in the first striped superconductor
Since y is bent due to the minor effect t in the second striped superconductor 10, it returns to its original position in the lower part of the second striped superconductor l, and the magnetic field on the recording medium 5 is , works in the same way as without the second striped superconductor l.

This composite magnetic field Ht f magnetizes the magnetic storage medium 5 in the direction of the vector of Ht. Here, the magnetic field generated by the first striped superconductor 2 is calculated.

According to Ampere's law of circuit integration, the cross-sectional shape of the striped superconductor is a square of 0.5 μm, the thickness of the insulating layer 3 is 0.1 μm, and the current flowing through the striped superconductor is 200 μm.
Calculating the magnetic field on the magnetic storage medium with mA and 300mA, when i = 200mA, Hx = 8000e, i
= 300mA, HX = 12000e is obtained. The current density at this time is J = 8 x 10'A/cd (i =
200 mA) and J = 1.2X I O”
A/CI7! (i = 300 mA),
The combined magnetic field Ht becomes 11200e and 16800e.

For example, according to the literature, if a NbCN superconductor is used, a critical current density Jc = 10''A/cII can be obtained, so recording is sufficient compared to a high Hc medium (Hc = 600-800). By reversing the current directions of the tC current Ix and the current y, a magnetic field in the opposite direction to the above-mentioned combined magnetic field Ht can be obtained as shown in FIG. 5(d).

This composite magnetic field Ht magnetizes the magnetic storage medium 5 under the orthogonal point of the first and second striped superconductors 2 and 1 in opposite directions. If one direction (135°) of the magnetization state corresponds to data 1"l, and the opposite direction (-45°) corresponds to @0", the first and second striped superconductors ( Information is stored in the magnetic storage medium 5 under the orthogonal point of 1 and 2).
1" and "0" can be recorded. The state of magnetization recorded in this way is shown in FIG.

Next, the case of reproducing the magnetization M recorded on the magnetic storage medium 5 will be explained with reference to FIG. A striped magnetoresistive element 7 exists below the magnetic storage medium 5 via an insulating layer 6, and a striped magnetoresistive element 7 exists below the striped magnetoresistive element 7 via an insulating layer 12. A third striped superconductor 8 is present perpendicular to the element 7.

Assume now that the magnetization M of the magnetic storage medium 5 is at an angle of +135° with respect to the current vector IMR flowing through the striped magnetoresistive element 7, as shown in FIG. In this state, the magnetic field HM generated by the magnetization M at the orthogonal points and applied to the striped magnetoresistive element 7 has an angle of 145° with respect to the current vector IMR, as shown in FIG.

Here, a sense current l is applied to the third striped superconductor 8.
When 5e (pulse) is applied and a sense magnetic field Hse is generated by Ise in the same direction as the current vector IMR at the orthogonal point of the magnetoresistive element 7, HM and Hse are generated to the extent that they overcome the demagnetizing field in the width direction of the MR stripe. The resultant magnetic field approaches the direction of the current vector IMR from the HM direction (-45°).

Next, when the magnetization of the orthogonal point on the magnetic storage medium 5 is opposite to the magnetization state of the magnetic storage medium (corresponding to data 10'') as shown in FIG. 5 (Φ), the third When a sense current l5e (pulse) is passed through the striped superconductor 8, a magnetic field Hse is generated at the orthogonal point, and the angle of the combined magnetic field Ht of HM and Hse is +135° of H with respect to the current vector IMR. becomes smaller (Fig. 7 (ψ), +90
° Control Hse so that it is close to . Here, the change in resistance R due to the applied magnetic field H of the striped magnetoresistive element 7 is shown in FIG.
→, the magnetization direction of the magnetic storage medium 5 is -45° or +135° with respect to the direction of the current IM of the magnetoresistive element 7.
゜, but on this R-H curve, θ=-
Point A at 45° corresponds to data 11”, θ=+135
Point B at ° corresponds to data 10".The resistance value itself is θ
There is no change at =+135° and -45°.

In this state, the third striped superconductor 8
When a sense current Ise (pulse) is applied to the sense current Ise and an induced magnetic field Hse is applied, the point A in Figure 8 (,0 changes in the direction of the arrow, and the resistance value becomes IS
It increases only when a current pulse of e is applied. Furthermore, in Fig. 8 (resistance value R with respect to point B (corresponding to “0”) on the fathom
decreases only when a current pulse of Ise is applied. Therefore, in order to convert these respective resistance changes into voltages, a pulse corresponding to data "1" and a pulse corresponding to data "O" are obtained with opposite polarity, as shown in FIG.
Data can be played back.

For example, for Ni ss Fel'e, T = 4.2
Δ at °K? / 9 o = 16.4 fo MR element (specific resistance f'.

=4.75Ω) was obtained. Therefore, if the stripe width is 0.5 μm and the thickness is 0.05 μm, then per bit =
0.95Ω, and the resistance change amount △ with respect to this value Rxf
R1=0.95×0.164=0.1558Ω.

Therefore, the current i flowing through the striped magnetoresistive element 7
When i=1mA, the playback output e is 0.1558m
V, and if i=2mA, the playback output e is 0.311
Since the voltage is 6 mV, a sufficiently practical value can be obtained. Here, the resistance and voltage across the striped magnetoresistive element 70 are 48.3 Ω and 48.3 V (i =
1 mA), 96 V (for i= and θ=+135° a pulse as shown in FIG. 8 (sometimes) is obtained.

Here, the striped superconductor is made of NbCN, the striped magnetoresistive element is made of Ni-Fe%NiCo, etc., and the insulating layer is made of AA20! , 5 iOz, silicon nitride, etc., and polished Si is suitable for the substrate. In addition, the solid magnetic memory device section is formed by sputtering, ion milling, X-ray exposure (
or optical exposure), polishing, and other thin film forming techniques can be used.

Note that the striped patterns formed on both main surfaces of the magnetic storage medium layer do not have to be orthogonal. Furthermore, the widths of the patterns do not all have to be the same.

Furthermore, the magnetic storage medium portion in which the superconductor and magnetoresistive element are formed and the necessary peripheral circuit portion are placed in an extremely low temperature environment.

One layer of the multilayer solid-state magnetic memory element of this example is shown in Figure 2 (
(playback system), as shown in Figure 2 (recording system), and these are 3
A multilayer solid-state magnetic memory with a structure in which layers are bonded together was fabricated. A third striped superconductor (NbCN) 8 with a stripe width of 0.5 μm is formed on the substrate 13 by sputtering and pattern etching using ion milling. top l
(siot) is formed on this insulating layer by sputtering, and after removing the step difference on the surface of the insulating layer (Sin2) by an etch-back method using ion milling to make the surface flat, the insulating layer 12 (Sing) is formed. A striped magnetoresistive element 7 (NiFe) with a stripe width of 0.5 μm orthogonal to the striped superconductor 8 is formed thereon by sputtering and etching by ion milling to produce a striped magnetoresistive effect. After forming an insulating layer 6 (SiOz) on the entire surface including the top of the element by sputtering and removing the level difference, a magnetic recording medium 5 (CoPt) is uniformly formed on the entire surface of the insulating layer 6 by sputtering. An insulating layer (Sin2) is formed on the magnetic storage medium 5 by sputtering, and a stripe @0.5μ is formed on the insulating layer 4.
A second striped superconductor 1 (NbCN)' of m is formed by sputtering and etching by ion milling.
A first striped superconductor 2 of 0.5 μm is formed on the insulating layer 3 so as to be perpendicular to the second striped superconductor. (NbCN) was formed by sputtering and etching by ion milling. Three connection layers (120, 12
1), a three-layer structure was bonded and wiring was applied. The superconductor portion thus formed was operated at an extremely low temperature of about 42°K (liquid helium).

Note that the distance between the stripes of each striped superconductor and striped magnetoresistive element 7 is 0.5 μm.
The thickness t is 0.5 μm (stripe superconductor) and 0.05 μm (stripe magnet).

The stripe was formed with a stripe length t of 1 inch.

In this embodiment, one bit has a size of 1μ7FIX1μm, and an areal density of 6.45XlO' bits square inch was achieved. Furthermore, reducing the stripe width increases the capacity per square inch. Furthermore, in the case of the aforementioned bit size of 1μ7FIX1μm, if a 25-inch square substrate is used for a single-layer solid-state magnetic memory element, a three-layer structure can be realized with three substrates, and the memory capacity will be approximately 3 gigabytes (GB). becomes possible.

〔Effect of the invention〕

As explained above, the present invention eliminates the mechanical durability required for the rotation mechanism and disk head system of conventional magnetic disk drives, and has a large capacity (1.5 x 10').
We were able to obtain a non-volatile solid-state magnetic file memory with a capacity of bits per million inches or more.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view including an embodiment of the present invention and a peripheral circuit, FIG. 2 is a schematic perspective view showing a part of the memory device shown in FIG. 1, and FIGS. FIG. 6 is a partial perspective view showing the magnetization state of the magnetic storage medium, FIG. 7(a), (
b) and (c) are partial perspective views, magnetization characteristic diagrams, and vector diagrams of the element that explain the operation during reproduction in Figure 1, and Figures 8 (a) and (b) explain the operation of this embodiment. They are a magnetization characteristic diagram and an output waveform diagram. 1... Second striped superconductor, 2...
...First striped superconductor, 8...Third striped superconductor, 3.4, 6, 12.13.
...Insulating layer, 5...Magnetic storage medium, 7.
...Stripe magnetoresistive element, 9...
...Resistance, 11...Substrate, 14...C
PU and interface, 46...first X
Axis address register, 18... gl y-axis address register, 44... gl x-axis address decoder, 19... first ym address decoder, 45... ...Flipf n tube for data, 47~
52...--and gate, 16.17,30,3
1゜33...Current source, 20~29...
First switch group, 32.34.39-=40...
...Second switch group, 36...Second y-axis address register (for playback), 42...Second X
Axis address register, 35... Second y-axis address decoder, 41... Second X fine address decoder, 43... Reproduction circuit system, 100, 101
,102...Solid magnetic memory element, 120,
121...Adhesive layer, 130...Buffer register. Agent Patent Attorney Uchihara Shinjo 3 figures kayu 4 figures Ayo 11 children Tao Kuniko 2 figures

Claims (1)

[Claims] A plurality of second striped superconductors are formed at predetermined intervals on one main surface of the magnetic storage medium layer with an insulating layer interposed therebetween, and these second striped superconductors and the magnetic storage A plurality of first stripe-shaped superconductors are formed at predetermined intervals on the main surface of the medium layer so as to intersect each of the second stripe-shaped superconductors at a predetermined angle via an insulating layer. A plurality of striped magnetoresistive elements are formed on the other main surface of the magnetic storage medium layer with an insulating layer interposed therebetween, and a plurality of striped magnetoresistive elements are formed on the main surface of the magnetic storage medium layer and the striped magnetoresistive elements. A plurality of third striped superconductors are formed on the top with an insulating layer interposed therebetween at predetermined intervals, and the intersection portions of the first and second striped superconductors and the third striped superconductors A multilayer solid-state magnetic memory characterized in that a plurality of solid-state magnetic memory elements are laminated in a plurality of layers, the solid-state magnetic memory elements being arranged in positions where the body and the intersection of the striped magnetoresistive elements face each other with the magnetic storage medium layer interposed therebetween. element.