JP2001266565A - Magnetic memory element and magnetic memory using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic memory element which can perform efficiently write-in and erasion by a heating means and a magnetic memory using it. SOLUTION: This magnetic memory element has a magnetic field control section having closed shape in which a closed magnetic path can be substantially constituted, a magnetic storage section which is extended to the inside of the closed shape from two parts of the magnetic control section so as to bi-sect the closed shape, while in which a gap is formed in respective extended opposing members, and a magnetic field detecting means provided near the gap of the magnetic storage section. The magnetic field control section is provided with switch sections for cutting a closed magnetic path respectively in bi-sected closed shapes. The device is constituted so that magnetizing directions of the magnetic storage section are reversed to each other by cutting alternately a closed magnetic path of the magnetic field control section by the switch section formed in each of bi-sected closed shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a solid-state memory for recording information according to the magnetization direction of a magnetic material, that is, a magnetic memory and a magnetic memory element used for the same.

[0002]

2. Description of the Related Art Solid memories made of magnetic materials have long been proposed as core memories made of ferrite, and subsequently, wire memories, bubble domain memories, Bloch line memories, and the like. Effect memory MRAM (magnetoresistive r
andom access memory).

[0003] In 1972, the use of a magnetoresistive film for solid-state memory was described by LJ Schwee in Proc. INTERMAG Con.
f. Although reported in IEEE Trans. Magn., Kyoto, p. 405 (1972), the output was too low to be practical. After that, a giant magnetoresistance effect which can obtain a larger output was found, and studies on MRAM using the giant magnetoresistive effect became active, and reports on various types of MRAM have been made. For example, Sakakima et al. Reported an example in the Journal of the Japan Society of Applied Magnetics, 20, 22 (1996).
As shown in FIG. 13A, it is composed of a laminate of a write line W, an insulating film 113, a hard magnetic film 111, a conductive film 114, and a soft magnetic film 112. In this memory element, as shown in FIG. 13A, an upward current with respect to the paper surface is applied to the write line W, and the state in which the hard magnetic film 111 is magnetized rightward is shown as "1" in FIG. 13B. The opposite is set to “0” so that

The read method does not affect the hard magnetic film 111 as shown in FIG.
The soft magnetic film 112 applies a positive / negative current pulse of a magnitude that can be reversed to the write line W, applies a detection current to the element and confirms it. If the resistance change ΔR is positive or negative, “1”
"0" is determined. In the state on the left side of FIG. 13C, since the magnetization directions of the hard magnetic film 111 and the soft magnetic film 112 are opposite to each other after the application of positive and negative current pulses, the resistance change ΔR has a positive value. In the state on the right side of FIG. 13C, since the magnetization directions of the hard magnetic film 111 and the soft magnetic film 112 are the same after the application of the positive and negative current pulses, the resistance change ΔR has a negative value.

[0005] As described above, the memory based on the GMR operates so as to perform the magnetization reversal by the magnetic field generated by the current. However, it is necessary to flow a large current, albeit instantaneously, to generate a magnetic field. Since the magnetic field due to the current and the magnetic film are not sufficiently efficiently coupled, only part of the current actually contributes to the magnetization reversal. There is a problem. There is also a problem that the rise of the write current is delayed.

On the other hand, with respect to the control of the magnetization direction by heat, for example, thermomagnetic writing is performed as represented by a magneto-optical disk. However, in this case, the recording medium rotates, a laser is used as the heat source, and the laser itself is fixed to the optical head and moves. There is a problem.

As a solid-state memory utilizing heat,
Japanese Patent Application Laid-Open No. 4-23293 proposes an invention using a single-layer laminated magnetic film. According to this, the solid-state memory comprises a heating element, a magnetic thin film, a magnetoresistive element, a switching transistor for writing, a transfer gate for reading, and
It is configured to include two lead wires. In this case, the magnetic thin film is in a continuous state without element separation. Then, at the time of writing, a current is applied only to a predetermined memory element by the switching transistor to heat the magnetic film and reverse the magnetization direction. For reading, the direction of magnetization is detected by a magnetoresistive element. This requires a transfer gate formed of a semiconductor material for each memory element, and considering the heating means, since the magnetic film is continuous, the effect on adjacent memory elements cannot be ignored, and it is difficult to increase the density. There is a problem. In addition, this memory element cannot erase recorded bits unless a magnetic field perpendicular to the film surface is applied from the outside.

In order to solve such a problem, the inventors of the present application have proposed a method of forming a solid-state memory and thermally controlling the magnetization direction without using a continuous magnetic film as described above. A magnetic thin film memory has already been proposed (Japanese Patent Application No. 10-301614). According to this proposal, the present invention provides two types of magnetic films having different coercive forces, magnetic field detecting means, and magnetizing means for performing magnetization reversal of a film having a small coercive force among the two types of magnetic films. It has a configuration having both heating means. Although this proposal can solve the above-mentioned conventional problems, it requires both a magnetizing means and a heating means by a current or the like in order to repeat the magnetization reversal. Improvement is desired.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a magnetic memory device capable of efficiently performing writing and erasing by heating means. And a magnetic memory using the same.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a closed magnetic field control unit capable of substantially forming a closed magnetic circuit, and a closed magnetic field control unit having the closed shape. A magnetic storage unit extending from two locations of the magnetic field control unit toward the inside of the closed shape so as to divide the magnetic storage unit, and forming a gap in the extended members facing each other; A magnetic memory element having magnetic field detecting means provided in the vicinity, wherein the magnetic field control unit includes a switch unit for cutting a closed magnetic path in each of the two divided closed shapes, By alternately cutting the closed magnetic path of the magnetic field control unit by the switch unit formed in each of the closed shapes, the magnetization directions of the magnetic storage unit are reversed.

Further, the magnetic memory element of the present invention is provided with a soft magnetic material heated member whose switch section has a low Curie temperature and a heating means for heating the soft magnetic material heated member to a Curie temperature or higher. It is configured as follows.

Further, in the magnetic memory element according to the present invention, the magnetic field control section includes a low-Curie temperature soft magnetic material-heated member forming a part of a switch section, and a hard magnetic material member for regulating a magnetic field direction of a closed magnetic circuit. And a high Curie temperature soft magnetic material member, and the magnetic storage section is configured to include a magnetically recordable high Curie temperature semi-hard magnetic material.

Further, in the magnetic memory element of the present invention,
Opposing members constituting the gap portion of the magnetic storage unit are each formed of a semi-hard magnetic material having a high Curie temperature.

Further, in the magnetic memory device of the present invention,
One of the members constituting the gap portion of the magnetic storage unit is formed of a soft magnetic material having a high Curie point.

Further, the magnetic memory element according to the present invention comprises:
It is configured on a plane or three-dimensionally.

The magnetic memory of the present invention comprises the magnetic memory elements arranged in a matrix.

According to the present invention described above, it is possible to realize a nonvolatile magnetic solid-state memory in which information can be written / erased only by thermal means and does not require a mechanical operation.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the magnetic memory device according to the present invention will be described below in detail. The magnetic memory element of the present invention may be configured on a plane (configured as a thin film) or may be configured three-dimensionally.

First of a magnetic memory element formed on a plane
Is shown in FIG.

As shown in FIG. 1, the magnetic memory element 1
Is configured such that a magnetic field control unit 10 having a closed shape (in the case of FIG. 1, a substantially square shape) capable of substantially configuring a closed magnetic path forms an outer frame of the element.

A substantially rectangular magnetic field control unit 1 shown in FIG.
0 is a hard magnetic material member 12, 12 'made of, for example, SmCo arranged diagonally, and a soft magnetic material member 1 made of, for example, Gd and made of, for example, Gd and having a low Curie temperature.
1, 11 ′ (a member to be heated with a soft magnetic material), soft magnetic material members 13, 13 ′ made of, for example, permalloy (NiFe) having a high Curie temperature and arranged vertically opposite to each other in the drawing, and the hard magnetic material member 12, Soft magnetic material members 14, 14 'made of, for example, permalloy interposed between the 12' and the low Curie temperature soft magnetic material members 11, 11 ', respectively.
Are formed so as to form a substantially square shape.
In particular, the hard magnetic material members 12, 12 'function to regulate the direction of the magnetic field of the closed magnetic circuit, as will be understood from the following description.

As shown in FIG. 1, the closed shape of the magnetic field control unit 10 is further divided into two parts (points P and P in FIG. 1) so as to bisect the closed substantially square shape of the magnetic field control unit 10. The magnetic recording members 21 and 21 are extended toward the inside to form a main part of the magnetic storage unit 20. Magnetic recording member 2
A gap G is formed between the opposing members 21a and 21a of the first and the second 21 and a magnetic field detecting means 27 for detecting a magnetic field is provided near the gap G. If the magnetic field detecting means 27 can detect the magnetic field direction,
Any magnetic field sensor can be used, for example, a Hall element or various magnetoresistive elements.

The magnetic field control unit 10 according to the present invention is provided with a switch unit for cutting a closed magnetic path in each of the closed shapes divided by the magnetic storage unit 20. That is, heating means 19, 19 such as heaters for heating the members 11, 11 'to a temperature higher than the Curie temperature are provided at the positions of the soft magnetic material members (soft magnetic material heated members) 11, 11' having a low Curie temperature. (A switch unit is constituted by the member 11 (11 ') and the heating means 19 (19')). The heating means 19 and 19 'are as described above in which the soft magnetic material member 1 having a low Curie point is used.
A heater which can be electrically heated may be provided adjacent to 1, 11 ', or the soft magnetic material may be directly energized.

The switching directions of the closed magnetic circuit of the magnetic field control unit 10 are alternately performed by these switches, so that the magnetization directions of the magnetic storage unit 20 are reversed. This will be described in detail later in the operation principle of the magnetic memory element.

In the embodiment shown in FIG.
The magnetic recording members 21 and 21 are composed of semi-hard magnetic material members 21 and 21 of a high Curie temperature semi-hard magnetic material made of, for example, carbon steel so that the state of magnetic recording can be maintained. In the present invention, “high Curie temperature” means
It is defined as a Curie temperature higher than the temperature when the heating means is energized, and the `` low Curie temperature '' is
It is defined as the Curie temperature lower than the temperature when the heating means is energized.

[Operation Principle of Magnetic Memory Element] The operation principle of the magnetic memory element 1 of the present invention will be described with reference to FIG.

In FIG. 1, the magnetic field control unit 10 is formed by a substantially rectangular magnetic circuit (closed magnetic circuit). The magnetization directions of the hard magnetic material members 12 and 12 ′ that regulate the magnetic field direction of the closed magnetic path of the magnetic field control unit 10 are indicated by the same direction in the magnetic circuit (in the example of FIG. 1, arrows (α) and (β)). Clockwise direction).

When the magnetization directions of the magnetic recording members (semi-hard magnetic material members) 21 and 21 of the magnetic storage unit 20 are upward in the drawing, the state is recorded "1", and when the magnetization direction is downward, the state is recorded "0". .

The state of the record "1" corresponds to the heating means 19 provided on the soft magnetic material member 11 having a low Curie point on the left side of the drawing.
Is operated to heat the soft magnetic material member 11 above the Curie point. Then, the heated portion changes from ferromagnetic to paramagnetic, the magnetic circuit is cut, and the magnetic flux (arrow (β)) generated by the right hard magnetic material member 12 ′ flows toward the magnetic storage unit 20. This can be realized by that the magnetization directions of the magnetic recording members (semi-hard magnetic material members) 21 and 21 of the magnetic storage unit 20 face upward. In this case, since the magnetic recording members (semi-hard magnetic material members) 21 and 21 of the magnetic storage unit 20 are made of a semi-hard magnetic material, the same state (even if the heating of the soft magnetic material member 11 on the left side is completed). Semi-hard magnetic material members 21, 21
Magnetization direction does not change).

Similarly, the state of recording "0" (which may be considered as the state of erasure "0") corresponds to the heating means 1 provided on the low-Curie temperature soft magnetic material member 11 'located on the right side of the drawing.
When the 9 'is operated, the heated portion changes from ferromagnetic to paramagnetic, the magnetic circuit is cut, and the magnetic flux (arrow (α)) created by the left hard magnetic material member 12 is stored in the magnetic storage unit 20. And the magnetization directions of the magnetic recording members (semi-hard magnetic material members) 21 and 21 of the magnetic storage unit 20 are directed downward.

Another embodiment of the magnetic memory device of the present invention
The following describes in detail another embodiment (an aspect other than that shown in FIG. 1) of the magnetic memory element of the present invention.

FIG. 2 shows a second embodiment of the magnetic memory element of the present invention. The magnetic memory element 2 shown in FIG. 2 differs from the element 1 shown in FIG. 1 in that the shape of the magnetic field control unit 10 has been changed from a substantially square shape to a circular shape.
There are no other substantial changes, and the same reference numerals in FIGS. 1 and 2 indicate substantially the same members. In the case of the second embodiment shown in FIG.
There is an advantage that it can be made smaller than the first embodiment shown in FIG.

FIG. 3 shows a third embodiment of the magnetic memory element of the present invention. The magnetic memory element 3 shown in FIG. 3 differs from the element 1 shown in FIG. 1 in that the shape of the entire element has been changed from a planar configuration to a three-dimensional configuration. Other than that, there is no substantial change, and FIGS. 1 and 3
, The same reference numerals indicate substantially the same members. In the case of the third embodiment shown in FIG. 3, there is a merit that a three-dimensional arrangement can be easily performed and the element arrangement is suitable for high density.

FIG. 4 shows a fourth embodiment of the magnetic memory element of the present invention. The magnetic memory element 4 shown in FIG. 4 is different from the element 1 shown in FIG. 1 in that the magnetic storage unit 20 is not entirely composed of magnetic recording members 21 and 21 made of a semi-hard magnetic material. 20 is a soft magnetic material member 2
3,23 and magnetic recording members 21,2 made of semi-hard magnetic material
1 in that it is configured in combination. Of course, magnetic recording members 21 and 21 made of a semi-hard magnetic material are arranged closer to the gap as shown. There are no other substantial changes, and the same reference numerals in FIGS. 1 and 4 indicate substantially the same members. In the case of the fourth embodiment shown in FIG. 4, since a semi-hard magnetic material having a higher coercive force can be used than in the first embodiment shown in FIG. 1, there is an advantage that the storage state is stabilized.

FIG. 5 shows a fifth embodiment of the magnetic memory element of the present invention. The magnetic memory element 5 shown in FIG. 5 differs from the element 4 shown in FIG. 4 in that a magnetic recording member 21 made of a semi-hard magnetic material is used only on one side at the gap position of the magnetic storage unit 20. (The other, in which the magnetic recording member 21 made of a semi-hard magnetic material is not used, is composed of only the soft magnetic material member 23 as shown). There is no other substantial change, and the same reference numerals in FIGS. 4 and 5 indicate substantially the same members. In the case of the fifth embodiment shown in FIG. 5, a semi-hard magnetic material having a higher coercive force can be used than in the first embodiment shown in FIG.

FIGS. 6A and 6B show a sixth embodiment of the magnetic memory element of the present invention. FIG.
It is an AA arrow line view (a side view) of (a). The magnetic memory element 6 shown in FIG. 6 differs from the element 1 shown in FIG. 1 in that the configuration of the magnetic field control unit 10 is basically different.
That is, as shown in FIG. 6B, the element 6 includes a pair of hard magnetic material members 16a and 16a made of NdFeB, for example.
Due to the magnetization of the predetermined direction 16b, as shown in FIG. 6A, a soft magnetic material member 15 'made of, for example, permalloy is formed.
, A magnetization direction indicated by an arrow (β) is formed. Similarly, the magnetization direction of the arrow (α) is formed in the soft magnetic material member 15 made of, for example, permalloy by the magnetization of the pair of hard magnetic material members 16c and 16d made of, for example, NdFeB formed at the opposing positions. Thus, the magnetic circuit of the magnetic field control unit 10 is formed clockwise in the drawing.

Such a substantially square closed shape is divided into two by, for example, a magnetic recording member 21 made of Co semi-hard magnetic material, and the two divided closed shapes are used to cut a closed magnetic path. Is configured. FIG.
The switch section of the first embodiment is composed of soft magnetic material-heated members 11, 11 made of, for example, Gd and having a low Curie temperature, and heating means 19, 19 'such as a heater. Note that reference numeral 1
Reference numerals 7, 17 'and 18 denote soft magnetic material members made of, for example, NiFe, and the same reference numerals in FIGS. 1 and 6 denote substantially the same members. In the case of the sixth embodiment shown in FIG. 6, there is an advantage that a perpendicular magnetization hard magnetic material can be used.

[Operation Principle of Magnetic Memory] The operation principle of the magnetic memory element of the present invention has been described above. The operation principle of the entire magnetic memory formed by integrating a plurality of magnetic memory elements is shown in FIGS. It will be described based on the following. Here, in order to easily understand the function as the magnetic memory, an extremely simple 2
× 2 memory (the magnetic memory element 1 shown in FIG. 1)
(A form in which four are arranged) will be described.

FIG. 7 shows memory elements M11, M12, M21, and M21 arranged so that the operation of the magnetic memory can be easily understood.
Only M22 is described, FIG. 8 shows only a write line for recording, and FIG. 8 shows only a read line for recording separately.

As can be seen from these figures, a plurality of memory elements M11, M12, M21, M22 are arranged in a matrix as shown in FIG. 7, and these individual elements are shown in FIG. As described above, two write lines are arranged vertically and one write line is arranged horizontally. That is, the memory element M1
For W1, two write lines W01A and W01B are arranged vertically and one write line W10 is arranged horizontally. For the memory element M12, two write lines W02A and W02B are vertically arranged and one write line W10 is arranged horizontally. For the memory element M21, two write lines of W01A and W01B are arranged vertically, and for the memory element M22, one write line of W20 is arranged, and for the memory element M22, two lines of W02A and W02B are vertically arranged. One write line of W20 is arranged laterally.

Each of these write lines is connected to heaters 19 and 19 'of each element as shown in the figure. For example, when the heater 19 is energized, "1" is recorded in the magnetic storage unit 20. In addition, by energizing the heater 19 ′, “0” is recorded (erased) in the magnetic storage unit 20.

Further, as shown in FIG. 9, one vertical and horizontal readout line is arranged for one element. That is, for the memory element M11, one read line of R01 is arranged vertically and one read line of R10 is arranged horizontally, and for the memory element M12, one read line of R02 is vertically arranged and one read line of R10 is arranged horizontally. For the memory element M21, one read line of R01 is arranged vertically, and one read line of R20 is arranged horizontally. For the memory element M22, one read line of R02 is arranged vertically and the read line of R20 is arranged horizontally. One read line is arranged. Then, the magnetic field detecting means 27 is connected to the readout lines corresponding to each of these elements, whereby the discrimination of the recording of "1" or "0" is performed.

A more detailed and specific operation will be described once again just in case. For example, in the configuration shown in FIGS. 7 to 9, to write “1” to the memory element M 11 in FIG.
A voltage is applied to both ends of 1A and W10 to make the magnetization direction of the magnetic storage unit of M11 upward. "0" for the memory element of M11
Is written, a voltage is applied to both ends of W01B and W10 to lower the magnetization direction of the magnetic storage unit of M11 downward. M11
In the reading of, the detection current flows to the read lines R10 and R01,
"1" and "0" are determined based on the difference between the voltages at both ends. In the above embodiment, W10 and R10 may share one line.

As described above, the magnetic memory according to the present invention comprises:
The operation of writing / erasing and reading is simple, and signal processing before and after the operation is extremely easy.

[0045]

The present invention will be described below in more detail with reference to specific examples of the present invention.

[Example 1] In Example 1, the function was confirmed using a memory element manufactured with a configuration as shown in FIG. FIG. 10 is different from a normal drawing.
The specific material constitution of the present invention is specified directly in the drawings so that the constitution materials of the embodiments can be easily understood.

That is, as shown in FIG. 10, the magnetic field control unit 10 includes two SmCo-based materials as hard magnetic material members and two Gd at a Curie point of 20 ° C. as a low Curie point soft magnetic material member. Then, a closed rectangular shape was formed using four permalloy (Ni80Fe20) as soft magnetic material members having a high Curie point (formation of a closed magnetic path).

Each constituent material has a thickness of 2 mm and a width of 1.
0 mm plate shape, the overall size of the magnetic field control unit 10 is 50 × 6
0 mm. NiCr-based heaters 19 and 19 'were used for heating the soft magnetic material member Gd having a low Curie point.

One side of the magnetic storage unit 20 extending toward the inside of the closed magnetic field control unit 10 has a thickness of 2 mm and a width of 1 mm.
A 1 mm thick carbon steel plate of a semi-hard magnetic material having a thickness of 1 mm and a size of 3 × 3 mm is attached to the tip of a 0 mm plate-shaped permalloy NiFe (a soft magnetic material having a high Curie point), and the other of the magnetic storage unit 20 is made of only permalloy NiFe. And

The gap of the magnetic storage unit 20 is 3 mm,
At this gap position, a magnetic field sensor (magnetic field detecting means) composed of a Hall element for magnetic field detection was arranged.

The memory element thus constructed is stored at 5 ° C.
Then, the left heater 11 was energized to raise the temperature of the soft magnetic material member Gd to 40 ° C., and the magnetic field of the magnetic storage unit 20 was measured by the magnetic field sensor. As a result, 8
A magnetic field of 640 A / m was obtained.

Next, the heater on the left side was turned off, and the temperature was 5 ° C.
Then, the magnetic field of the magnetic storage unit 20 was measured by a magnetic field sensor, and it was confirmed that a magnetic field of 40 A / m remained.
This corresponds to a so-called “1” recording state.

Next, the right heater 19 'was energized to raise the temperature of the soft magnetic material member Gd to 40 ° C., and the magnetic field of the magnetic storage section 20 was measured by a magnetic field sensor. As a result, the magnetic storage unit 2
A magnetic field of 8880 A / m was obtained in the downward direction of 0. After the left heater 19 'was turned off and the temperature returned to 5 ° C., the magnetic field of the magnetic storage unit 20 was measured, and it was confirmed that a magnetic field of 48 A / m remained downward. This corresponds to a recording state of “0”. Thus, it was possible to confirm the function of the nonvolatile memory capable of writing and erasing only by heating by the heater.

[Embodiment 2] In Embodiment 2, FIG.
The function was confirmed using a memory element manufactured with a configuration as shown in (a) and (b). Note that FIG.
Also in (a) and (b), unlike the ordinary drawings, the specific material constitution of the present invention is specified directly in the drawings so that the constituent materials of the examples can be easily understood.

That is, in the second embodiment, as shown in FIG. 11 (substantially the same element configuration as in FIG. 6), NdFeB-based magnets 16a, 16b, 16 having an outer diameter of 10 mm and a height of 10 mm are used.
This is an example in which c and 16d are used in four places. Magnetic field control unit 10
Has a Curie point of 2 as a soft magnetic material with a low Curie point.
Gd at 0 ° C. was used in two places, and permalloy (Ni80Fe20) was used as a soft magnetic material member having a high Curie point in five places to form a closed square shape (formation of a closed magnetic path). Each material was a plate having a thickness of 2 mm and a width of 10 mm, and the overall size of the magnetic field control unit 10 was 50 × 60 mm. NiCr-based heater 1 is used for heating the soft magnetic material member Gd having a low Curie point.
9, 19 'were used.

The configuration of the magnetic storage unit 20 was in accordance with the drawings, and the configuration of the magnetic field detecting means 27 was the same as in the first embodiment. When the recording state was confirmed in the same manner as in Example 1 above using the sample of Example 2 thus produced,
A result similar to that of Example 1, that is, a function of the nonvolatile memory capable of writing and erasing only by heating by the heater could be confirmed. Incidentally, the residual magnetic field corresponding to the recording state of “1” was 45 A / m, and the residual magnetic field corresponding to the recording state of “0” was −46 A / m. In addition,
Minus the residual magnetic field means that the direction of the magnetic field is downward.

Example 3 In Example 3, the function was confirmed using a memory element manufactured with a configuration as shown in FIG. In FIG. 12 also, unlike a normal drawing, the specific material constitution of the present invention is specified directly in the drawing so that the constituent materials of the embodiment can be easily understood.

That is, as shown in FIG. 12, in the magnetic field control section 10, two SmCo-based materials are used as hard magnetic material members, and Gd at a Curie point of 20 ° C. is used as two soft magnetic material members having a low Curie point. A closed, substantially square shape was formed by using permalloy (Ni80Fe20) at four locations as a soft magnetic material member having a high Curie point (formation of a closed magnetic circuit). Each material was a plate having a thickness of 2 mm and a width of 10 mm, and the dimensions of the side surface of the magnetic field control unit were set to 50 × 60 mm.

For heating the soft magnetic material member Gd having a low Curie point, NiCr-based heaters 19 and 19 'were used. Carbon steel was used as a semi-hard magnetic material for the material on one side of the magnetic storage unit 20 (the portion up to the gap). The magnetic storage unit had a gap of 2 mm, and a magnetic field sensor (magnetic field detecting means) including a Hall element for detecting a magnetic field was arranged at the gap position. When the recording state was confirmed in the same manner as in Example 1 using the sample of Example 3 thus manufactured, the same result as in Example 1 was obtained, that is, the nonvolatile memory capable of writing and erasing only by heating with a heater The function of was able to be confirmed. By the way,
The residual magnetic field corresponding to the recording state of “1” is 52 A / m,
The residual magnetic field corresponding to the recording state of “0” was −56 A / m.

Fourth Embodiment In the first to third embodiments, the structure, manufacturing method, and function method of each memory element have been described. In the fourth embodiment, a plurality of memory elements are arranged in a matrix. 1 shows an embodiment of a magnetic memory arranged in a shape.

As shown in FIG. 7, for the basic operation check, the simplest matrix configuration is two columns vertically and two rows horizontally.
One write line vertically (see FIG. 8) and one read line each vertically and horizontally (see FIG. 9) for each of the four memory elements in total are 0.3 mm in thickness. Of copper wire. That is, the memory element of the first embodiment is replaced with 4
8 and 9, the connection arrangement state with each write line and read line was as shown in FIGS.

Next, the function of the memory was confirmed on behalf of the M21 memory element among the elements arranged in the matrix. That is, a voltage was applied to one end of each of the write lines W20 and W01A, and a current was supplied. Readout line R20, R
As a result of measuring the magnetic field from the voltage measurement at both ends of 01, the residual magnetic field of the magnetic storage unit was 40 A / m. Next, write line W2
A voltage was applied to one end of each of 0 and W01A to pass a current. As a result of measuring the magnetic field from the voltage measurement at both ends of the read lines R20 and R01, the residual magnetic field of the magnetic storage unit was -48 A / m. As a result, it was determined that the former was “1” and the latter was “0”.

In the above embodiment, an experiment was conducted by preparing a sample having a size that can be relatively easily manufactured at an experimental level in order to confirm the effect. However, in order to further increase the density, By making the element size extremely small using a thin film process or the like, a so-called magnetic thin film memory element or a magnetic thin film memory can be realized.

[0064]

The effects of the present invention are clear from the above results. That is, since the magnetic memory element of the present invention and the magnetic memory using the same are configured as described above, a nonvolatile magnetic solid-state that can write and read information efficiently and does not require a mechanical operation. This has the effect of being a memory.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing a preferred example of a magnetic memory element.

FIG. 2 is a schematic plan view showing another preferred example of the magnetic memory element.

FIG. 3 is a schematic perspective view showing another preferred example of the magnetic memory element.

FIG. 4 is a schematic plan view showing another preferred example of the magnetic memory element.

FIG. 5 is a schematic plan view showing another preferred example of the magnetic memory element.

FIG. 6A is a schematic plan view showing another preferred example of the magnetic memory element, and FIG. 6B is a view (side view) taken along the line AA of FIG.

FIG. 7 is a diagram for explaining the operation principle of the entire magnetic memory in the case of a simple 2 × 2 memory, in which only the arranged memory elements M11, M12, M21, and M22 are illustrated. .

FIG. 8 is a drawing for explaining the operation principle of the whole magnetic memory in the case of a simple 2 × 2 memory, and mainly includes:
It is a drawing in which only the recording write line is described.

FIG. 9 is a diagram for explaining the operation principle of the entire magnetic memory in the case of a simple 2 × 2 memory, and mainly includes:
It is a drawing in which only a read line for recording is described.

FIG. 10 is a drawing of a magnetic memory element for explaining Example 1;

FIG. 11 is a drawing of a magnetic memory element for explaining Example 2;

FIG. 12 is a drawing of a magnetic memory element for explaining a third embodiment.

FIG. 13 is a diagram for explaining the operation principle of the MRAM according to the related art.

[Explanation of symbols]

 1, 2, 3, 4, 5, 6 ... magnetic memory element 10 ... magnetic field control unit 11, 19; 11 ', 19' ... switch unit 20 ... magnetic storage unit 27 ... magnetic field detecting means

 ──────────────────────────────────────────────────の Continuation of the front page (72) Inventor Yoshikazu Narimiya 1-1-13 Nihonbashi, Chuo-ku, Tokyo Inside TDK Corporation

Claims (7)

[Claims] 1. A magnetic field control unit having a closed shape capable of substantially configuring a closed magnetic path, and a magnetic field control unit extending from two locations of the magnetic field control unit to the inside of the closed shape so as to bisect the closed shape. A magnetic memory element having a magnetic storage unit extending and forming a gap in the mutually extended members facing each other, and a magnetic field detecting means provided near the gap of the magnetic storage unit, The magnetic field control unit includes a switch unit for cutting a closed magnetic circuit in each of the two divided closed shapes, and the switch unit formed in each of the two divided closed shapes causes the magnetic field control unit to have a closed magnetic path. A magnetic memory element characterized in that the magnetization directions of the magnetic storage unit are reversed by alternately cutting the closed magnetic path. 2. The magnetic memory according to claim 1, wherein the switch section includes a member to be heated with a soft magnetic material having a low Curie temperature and heating means for heating the member with a soft magnetic material to be heated to a Curie temperature or higher. element. 3. The magnetic field control unit includes a low-Curie temperature soft magnetic material heated member that forms a part of a switch unit, a hard magnetic material member that regulates a magnetic field direction of a closed magnetic circuit, and a high Curie temperature soft material member. The magnetic storage section is configured to include a magnetic material member, and the magnetic storage section is configured to include a magnetically recordable semi-hard magnetic material having a high Curie temperature.
3. The magnetic memory element according to claim 1. 4. The magnetic memory device according to claim 3, wherein the opposing members forming the gap portion of the magnetic storage unit are each made of a semi-hard magnetic material having a high Curie temperature. 5. The magnetic memory device according to claim 3, wherein one of the members forming the gap portion of the magnetic storage unit is made of a soft magnetic material having a high Curie point. 6. The magnetic memory device according to claim 1, wherein said magnetic memory device is formed on a plane or three-dimensionally. 7. A magnetic memory, wherein the magnetic memory elements according to claim 1 are arranged in a matrix.