JPH11154389A - Magnetoresistive element, magnetic thin film memory element, and recording and reproducing method for the memory element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic thin film element, a magnetic thin film memory element, and a recording and reproducing method for this memory element in which a preservation state of magnetic information is high, high integration and reliability can be realized, stable recording/reproduction can be performed, manufacturing margin of a non-magnetic layer is wide, a reproducing time is short, and a reproducing method having less noise cn be realized. SOLUTION: A first magnetic layer 1 having closed magnetic path structure and a low coercive force a second magnetic layer 2 having closed magnetic path structure and a high coercive force are laminated through a non-magnetic layer 3 consisting of insulators 4, the first magnetic layer 1 and the second magnetic layer 2 have easy shafts of CCW or CW, and they have different resistance depending on a relative angle of the magnetization direction of the first and the second magnetic layers 1, 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive element for recording information by the direction of magnetization and reproducing the information by a magnetoresistance effect, and a magnetic thin film memory using the same.

[0002]

2. Description of the Related Art Like a semiconductor memory, a magnetic thin film memory is a solid-state memory having no moving parts, but does not lose information even when power is cut off, has an infinite number of rewrites repeatedly, and loses recorded contents when radiation enters. There are advantages such as no danger, as compared with semiconductor memories. In particular, in recent years, a thin film magnetic memory utilizing the giant magnetoresistance (GMR) effect has attracted attention because a large output can be obtained as compared with a conventionally proposed magnetic thin film memory using the anisotropic magnetoresistance effect. . For example, VOL. 20, P22
(1996) has a hard magnetic film HM as shown in FIG.
There has been proposed a solid-state memory in which a constituent element of a non-magnetic film NM / soft magnetic film SM / non-magnetic film NM is a memory element. This memory element is provided with a sense line S joined to a metal conductor, and a word line W insulated from the sense line S by an insulating film I. The sense line S is generated by the word line current and the sense line current. Information is written by a magnetic field. Specifically, as shown in FIG. 8, a current I is applied to the word line W to generate magnetic fields in different directions depending on the direction ID of the current to reverse the magnetization of the hard magnetic film HM, and to store the memory states “0” and “1”. Is recorded. For example, as shown in FIG. 7A, a positive current is applied to generate a rightward magnetic field to record "1" in the hard magnetic film HM, and a negative current is applied as shown in FIG. To generate a leftward magnetic field to record “0” on the hard magnetic film HM. In reading information, as shown in FIG. 9, a current I smaller than the recording current is applied to the word line W to cause only the magnetization reversal of the soft magnetic film SM, and the resistance change at that time is measured. If the giant magnetoresistance effect is used, the resistance values of the soft magnetic film SM and the hard magnetic film HM are different depending on whether the magnetization is parallel or antiparallel. The state can be determined. When a positive to negative pulse as shown in FIG. 3A is applied, the soft magnetic film turns from right to left, and for the memory state “1”, a small resistance value as shown in FIG. From (c) to a large resistance value as shown in FIG.
The resistance changes from a large resistance value as shown in FIG. 4D to a small resistance value as shown in FIG. If the change in resistance is read in this manner, information recorded on the hard magnetic film HM can be read regardless of the magnetization state of the soft magnetic film SM after recording, and nondestructive reading can be performed.

[0003]

However, in the magnetic thin film memory having the above structure, the demagnetizing field (self-demagnetizing field) generated inside the magnetic layer cannot be neglected as the area of the bit cell is reduced, and the magnetic thin film memory for recording and holding is not able to be stored. The magnetization direction of the layer is not determined in one direction and becomes unstable. Therefore, the magnetic thin film memory having the above configuration has a drawback that it is not possible to store information while miniaturizing the bit cell, and it is impossible to achieve high integration.

In view of these points, the present invention eliminates a demagnetizing field of a magnetic thin film, which is a problem when miniaturizing a bit cell,
An object of the present invention is to realize a magnetic thin film memory capable of high integration. Another object of the present invention is to realize a magnetoresistive element in which the magnetoresistance ratio does not decrease even when the size is reduced.

[0005]

The above object is achieved by the following means.

That is, according to the present invention, a first magnetic layer having a low coercive force in a cylindrical shape and a second magnetic layer having a high coercive force in a cylindrical shape are provided on a substrate via a nonmagnetic layer made of an insulator. The first magnetic layer and the second magnetic layer have easy axes counterclockwise or counterclockwise, and have different resistance values depending on the relative angles of the magnetization directions of the first and second magnetic layers. The non-magnetic layer is made of aluminum oxide, aluminum nitride, silicon oxide, or silicon nitride, and the thickness of the first magnetic layer and the second magnetic layer exceeds 100 angstroms. 5000 angstrom or less, and the thickness of the nonmagnetic layer is 5 angstrom or more and 3 angstrom or less.
0 Å or less, the coercive force of the first magnetic layer is less than half of the coercive force of the second magnetic layer, the coercive force of the first magnetic layer is 10 Oe to 50 Oe, and the coercive force of the second magnetic layer is An antiferromagnetic layer having a thickness exceeding 50 Oe is provided in contact with the surface of the second magnetic layer opposite to the nonmagnetic layer, and the antiferromagnetic layer and the second magnetic layer are exchange-coupled to each other. 2
The magnetization of the magnetic layer is fixed, a conductor surrounded by an insulator is formed at the center of the first magnetic layer and the second magnetic layer, and the coercive force of the second magnetic layer is 10 Oe or more. 5
The coercive force of the first magnetic layer is not more than 0 Oe, and includes not less than 2 Oe and not more than half of the coercive force of the second magnetic layer.

Further, the present invention proposes a magnetic thin film memory element comprising the above-mentioned magnetoresistive element, wherein the first magnetic layer and the second magnetic layer are made of Fe, Co, Ni.
Including at least one kind of element.

The present invention also provides a magnetic thin-film memory device in which a current is caused to flow perpendicularly to the film surface, and a magnetic field generated by the current determines the magnetization direction of the first magnetic layer, whereby the "0" and "1" are determined. It is intended to propose a recording method of a magnetic thin film memory characterized by recording a state,
The present invention proposes a reproducing method for a magnetic thin-film memory, characterized in that a current is passed through the magnetic thin-film memory element perpendicular to the film surface and the resistance is measured to detect magnetization information of "0" and "1". is there.

In the magnetic thin film memory according to the present invention, since the magnetic film has a closed magnetic circuit structure, it is possible to eliminate the adverse effect of the magnetic field and to stably store magnetization information. Therefore, the 1-bit cell width can be reduced, and a highly integrated magnetic thin film memory can be realized. Also, since the leakage magnetic field does not wet out to the adjacent cells,
Recording and reproduction of information can be performed more stably.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, each embodiment of the magnetic thin film memory of the present invention will be described in more detail.

[0011]

(Embodiment 1) FIG. 1 shows an example of a magnetic thin film memory element of the present invention, which is a cylindrical memory cell. FIG.
In the above, 1 is a first magnetic layer, 2 is a second magnetic layer, 3 is a non-magnetic layer, and a material made of an insulator is used to cause a spin tunnel effect as described later. Arrows indicate the magnetization direction in each magnetic layer. The first magnetic layer and the second magnetic layer are cylindrical, have an easy axis counterclockwise or counterclockwise, and their magnetizations are annularly oriented along the cylinder. Therefore, unlike the medium described in the related art, the magnetic pole does not come out to the end face, and stable magnetization can be stored.

The magnetization information of "0" and "1" is recorded according to whether the magnetization direction of the first magnetic layer is clockwise or counterclockwise. For example, FIG. 1A corresponds to “0” and FIG. 1B corresponds to “1”. The first magnetic layer has a low coercive force so that magnetization information can be recorded.

The second magnetic layer has a higher coercive force than the first magnetic layer, and its magnetization direction does not depend on magnetization information.
Oriented in a predetermined direction, when storing, recording,
During playback, it is always kept constant in any state.

Further, the magnetic thin film memory element of the present invention has a first
When the magnetizations of the magnetic layer and the second magnetic layer are parallel, a low resistance value is shown, and when the magnetizations are antiparallel, a high resistance value is shown. Therefore, the resistance value of the memory element varies depending on the magnetization direction of the first magnetic layer, and the recorded magnetization information can be read.

A giant magnetoresistive element of a spin tunnel type is used for the memory element of the present invention. This is for the following reason. The first is that a large magnetoresistance (MR) ratio can be obtained with the spin tunnel type. In a spin scattering type magnetoresistive element in which a nonconductive layer of a good conductor such as Cu is sandwiched between magnetic layers, only an MR ratio of about 10% is obtained.
In the spin tunnel type, the MR at room temperature is about 20 to 30%.
As a result, the signal at the time of reading can be increased. Second, the spin tunneling type magnetoresistive element can increase its resistance value to 1 kΩ or more. When the memory element of the present invention is arranged on a matrix and operated, the semiconductor switching element is connected to the memory element and used. However, the ON resistance of the semiconductor switching element (about 1 kΩ) is used. If it is smaller than about, the reading of information recorded in the memory element becomes unstable due to the influence of the variation in the on-resistance. Third, in the spin tunnel type, a CPP in which a current flows perpendicular to the film surface is used.
(Current Perpendicular to the film Plane)-MR
This is because the (Magneto-Resistance) effect can be used. This is when attaching the terminal to the memory element,
Attaching the electrode lines 6 and 7 above and below the memory element as shown in FIG. 2, as in the present invention, can ensure the contact between the memory element and the electrode line, rather than attaching the terminals in the lateral direction of the memory element. is there. In this respect, a magnetoresistance element of the spin scattering type can also observe the magnetoresistance by the CPP-MR effect, but is unsuitable as a memory element. This is because the spin scattering type magnetoresistive element has a resistance value of
Even when a current flows in parallel to the film surface, it is as small as several tens of ohms.
When the CPP-MR effect is used, the resistance value is further reduced by one digit or more, and reading cannot be performed accurately as described above.

(Embodiment 2) As described above, the magnetic thin film memory element of the present invention is characterized in that a magnetoresistance effect is generated by a spin tunneling type. The magnetoresistance effect by the spin tunneling has, for example, a structure of a first magnetic layer / nonmagnetic layer / second magnetic layer as shown in FIG. 1, but a thin insulating layer is used for the nonmagnetic layer. Then, when a current is caused to flow perpendicular to the film surface during reproduction, a tunnel phenomenon of electrons from the first magnetic layer to the second magnetic layer occurs.

In the spin tunnel type magnetic thin film memory element of the present invention, the conduction state of the ferromagnetic metal causes spin polarization, so that the electron states of the upward spin and the downward spin on the Fermi surface are different. When a ferromagnetic tunnel junction composed of a ferromagnetic material, an insulator, and a ferromagnetic material is made using such a ferromagnetic metal, the conduction electrons tunnel while keeping their spins. This changes the tunnel probability, which appears as a change in tunnel resistance. Thereby, the resistance is small when the magnetizations of the first and second magnetic layers are parallel, and the resistance is large when the magnetizations of the first and second magnetic layers are antiparallel. The larger the difference in the state density between the upward spin and the downward spin, the greater the resistance value, and a greater reproduction signal can be obtained. Therefore, the first magnetic layer and the second magnetic layer should be made of a magnetic material having a high spin polarizability. Is desirable. Specifically, the first magnetic layer and the second magnetic layer are formed by selecting Fe having a large amount of polarization of the vertical spin on the Fermi surface, and selecting Co as the second component. Specifically, it is desirable to use a material containing Fe, Co, and Ni as main components, and it is preferable to use Fe, Co, FeCo, NiFe, NiFeCo, or the like. The elemental composition of NiFe is NixFe100-
When x is set, x is desirably 0 or more and 82 or less. More specifically, Fe, Co, Ni72Fe28, Ni51F
e49, Ni42Fe58, Ni25Fe75, Ni9
Fe91 and the like.

Further, the first magnetic layer is more preferably made of NiFe, NiFeCo, Fe or the like in order to reduce coercive force. The second magnetic layer is preferably made of a material containing Co as a main component in order to increase the coercive force.

(Embodiment 3) As described above, since the magnetoresistive memory element of the present invention uses the magnetoresistance effect by spin tunneling, the non-magnetic layer is formed of an insulating layer because electrons hold spins and tunnel. There must be. The entire non-magnetic film may be an insulating layer or a part thereof may be an insulating layer. The magnetoresistive effect can be further enhanced by partially forming the insulating layer and minimizing its thickness.
Examples of an oxide layer formed by oxidizing a non-magnetic metal film include:
There is an example in which a part of the 1 film is oxidized in the air to form an Al ₂ O ₃ layer. The non-magnetic layer is made of an insulator, preferably aluminum oxide AlOx, aluminum nitride A
1Nx, silicon oxide SiOx, silicon nitride SiNx
Is desirable. NiOx may be the main component. This is because in order for spin tunneling to occur, it is necessary that an appropriate potential barrier exists for the energies of conduction electrons in the first magnetic layer and the second magnetic layer. Is relatively easy and is advantageous in production.

(Embodiment 4) It is desirable that the thicknesses of the first magnetic layer and the second magnetic layer of the magnetic thin film memory element of the present invention be more than 100 Å and not more than 5000 Å. First, when an oxide is used for the nonmagnetic layer, the effect of the oxide weakens the magnetism at the interface of the magnetic layer on the nonmagnetic layer side, and this effect is large when the film thickness is small. Second, the aluminum oxide nonmagnetic layer is
When oxidizing by introducing oxygen after forming Al, a few tens of angstroms of aluminum remain,
This is because when the magnetic layer has a thickness of 100 Å or less, the magnetic layer becomes too large to obtain an appropriate memory characteristic. Third, especially when the memory element is miniaturized to a submicron, the memory retention performance of the first magnetic layer is increased.
This is because the function of holding the constant magnetization of the second magnetic layer is reduced. On the other hand, if the thickness is too large, the resistance value of the cell becomes too large. Therefore, the thickness is preferably 5,000 Å or less, more preferably 1,000 Å or less.

On a Si substrate, NiF is used as the first magnetic layer 1.
e (film thickness t) and Al ₂ O ₃ (film thickness 10
Angstrom) and Co (film thickness t) as the second magnetic layer 2 were laminated in this order to produce a magnetic thin film memory element of the present invention having the configuration shown in FIG. NiFe, Al ₂ O ₃ , Co
The spin tunneling element section composed of was finely processed into a cylindrical shape having a diameter of about 0.8 μm by a focus ion beam. The thickness t of the magnetic layer ranges from 10 angstroms to 1
It was made by changing it to 0000 angstroms. A current was passed between the electrodes 6 and 7, and the resistance value was measured when the two magnetic layers were parallel and antiparallel. The MR ratio was defined as (maximum resistance-minimum resistance) / minimum resistance. The results are shown in the column of Experimental Example A in Table 1. The thickness of the magnetic layer is from 110 Å to 5000 Å,
The MR ratio was 15% or more, but was less than 10% in other cases. From 110 Å to 1000 Å, an MR ratio of 20% or more was obtained.

(Comparative Example 1) Next, FIG.
(A) composed of a spin scattering film (magnetic layer NiFe
(Thickness t), a nonmagnetic layer Cu (thickness 50 Å), and a magnetic layer Co (thickness t) were sequentially laminated) by changing the thickness of the magnetic layer in the same manner as described above to obtain a diameter of about 0.8 μm. Created by processing. Here, the spin scattering film is a giant magnetoresistive film in which a nonmagnetic layer sandwiched between two magnetic layers is formed of a good conductor. The measurement results of the MR ratio of this device are shown in the column of Comparative Example 1 in Table 1.

(Comparative Example 2) Next, as Comparative Example 2, a spin tunnel film of FIG. 7 having an open magnetic circuit configuration in which the magnetic path is not closed (SM in the figure is NiFe (thickness t), and NM is Al ₂ O ₃ (thickness: 15 angstroms), HM was Co (thickness: t)), and the diameter of the magnetic layer was changed to about 0.8 μm by changing the thickness of the magnetic layer in the same manner as described above. The measurement results of the MR ratio of this device are shown in the column of Comparative Example 2 in Table 1.

(Comparative Example 3) Next, as Comparative Example 3, the spin scattering film of FIG. 7 having an open magnetic circuit configuration in which the magnetic path is not closed (SM in the figure is NiFe (film thickness t), and NM is Cu (film) A thickness of 50 angstrom) and HM of Co (thickness t) were processed to a length of about 0.8 μm in the same manner as described above, and the MR ratio was measured. The measurement results of the MR ratio of this device are shown in the column of Comparative Example 3 in Table 1.

[0025]

[Table 1]

Table 1 shows that the spin tunneling device of the present invention has a higher MR ratio than the spin scattering device, and in particular, a high MR ratio can be obtained even when the magnetic layer is thickened. Further, the MR reduction in the open magnetic circuit configuration is caused by the fact that the magnetic layer thickness is 10
It becomes remarkable at 0 angstrom or more. This is presumed to be due to the fact that the demagnetizing field was reduced by the cylindrical shape, and the disturbance in the magnetization direction was reduced. However, in the case of the spin scattering film, when the thickness of the magnetic layer is 100 Å or more, the MR ratio is lowered even in the cylindrical type. This is because in the spin scattering film, when the thickness of the magnetic layer increases, the magnetoresistance effect itself hardly occurs.

Therefore, the demagnetizing field can be reduced by the cylindrical type.
The effect is more remarkable in the spin tunnel film than in the spin scattering film. In other words, it can be seen that the cylindrical configuration exhibits the effect of the spin tunnel element, and is a device that can cope with high integration.

(Embodiment 5) The non-magnetic layer has several tens of
It is a uniform layer having a thickness of about Å, and the thickness of the insulating portion is desirably not less than 5 Å and not more than 30 Å. This is because if the thickness is less than 5 angstroms, the first magnetic layer and the second magnetic layer may be electrically short-circuited. If the thickness exceeds 30 angstroms, electron tunneling is less likely to occur. It is. Furthermore, it is desirable that the thickness be 5 Å or more and 25 Å or less. More preferably, 5 angstrom or more and 1
8 angstroms is good.

Embodiment 6 The coercive force of the first magnetic layer of the magnetic thin film memory element of the present invention is 10 Oe or more and 50 Oe.
The following is desirable. This is because, during recording, a current flows through the memory element to reverse the magnetization of the first magnetic layer by a magnetic field generated at the time. Therefore, when the coercive force exceeds 50 Oe, the current required for the magnetization reversal increases, This is because the power consumption increases and the current density reaches the limit current density, and the memory element or the electrode line connecting the memory element and the switching element is disconnected. Also, it is difficult to stably store the magnetization information at 10 Oe or less. Further, the coercive force of the second magnetic layer desirably exceeds 50 Oe. This is because when the coercive force is weak, the magnetization is reversed during storage and recording, and reproduction cannot be performed.

For this reason, it is desirable that the coercive force of the first magnetic layer of the magnetic thin film memory element of the present invention is set to be less than half of the coercive force of the second magnetic layer.

The coercive force is controlled, for example, by adding Fe to Co, the coercive force decreases, and adding Pt, the coercive force increases. For example, Co100-xyFexP
The coercive force may be controlled by adjusting the element compositions x and y as ty. Since the coercive force can be increased by increasing the substrate temperature during film formation, another method of controlling the coercive force may be to adjust the substrate temperature during film formation. This method may be combined with the above-described method of adjusting the composition of the ferromagnetic thin film.

(Embodiment 7) In the magnetic thin film memory element of the present invention, an antiferromagnetic layer is provided in contact with the surface of the second magnetic layer opposite to the nonmagnetic layer, and the antiferromagnetic layer and the second magnetic layer The layers may be exchange coupled and the magnetization of the second magnetic layer may be fixed. The exchange coupling with the antiferromagnetic layer makes it possible to increase the coercive force of the second magnetic layer. In this case, the first magnetic layer and the second magnetic layer
Since the same material can be used for the magnetic layer, there is no need to sacrifice the MR ratio in order to increase the coercive force, and the range of material selection can be widened. Examples of the antiferromagnetic layer include nickel oxide NiO, iron manganese FeMn, and cobalt oxide CoO.

(Embodiment 8) FIG. 3 is a view showing another example of the magnetic thin film memory element of the present invention. In FIG. 3, the first magnetic layer 1
In the center of the second magnetic layer 2, a conductor 5 surrounded by an insulator 4 is formed. The conductor 5 is used for flowing a current during recording to reverse the magnetization, and has a higher conductivity than the magnetic layer. The insulator 4 is provided to prevent the conductor 5 from contacting the magnetic layer. FIG. 4 is a cross-sectional view of FIG. 3, in which sense lines 61 and 62 used for reproduction and a word line 7 used for recording are additionally shown in FIG. In FIG.
Although the sense line 62 also functions as a resistance electrode of the word line 71, a word line 72 is separately provided in FIG. In the structure shown in FIG. 5, the word line 7 is used for recording.
The recording is performed by applying a current to 1,72. At the time of reading, a current flows between the sense line 61 and the sense line 62,
Measure the resistance value of the memory element. Note that the sense lines 61,
The word lines 62 and the word lines 71 and 72 may be parallel or orthogonal. For example, in the structure shown in FIG. 6, the sense line 61 and the sense line 62 are parallel, and the word line 7 is provided orthogonal to the sense line 61 and the sense line 62.

In the structure shown in FIGS. 3, 4 and 5, FIG.
Compared to the structure of the above, since no current flows through the magnetic layer during recording, the wiring resistance is reduced, and the power consumption and the responsiveness are excellent.

(Embodiment 9) When recording is performed on the magnetic thin film memory element of the present invention, a current is caused to flow perpendicular to the film surface, that is, the current is made perpendicular to the magnetization method. The state of "0" and "1" is recorded by determining the magnetization direction of the first magnetic layer by the magnetic field generated by the current. The direction of the generated magnetic field differs depending on the direction of the flowing current. For example, when a current flows from top to bottom of a memory element, a magnetic field is generated clockwise when viewed from above the memory element, and magnetization is clockwise. Conversely, when current flows from bottom to top, the magnetization becomes counterclockwise. The first magnetic layer of the magnetic thin film memory element of the present invention has a small coercive force, and the second magnetic layer has a large coercive force. If the magnitude of the flowing current is set such that a magnetic field larger than the magnetization reversal magnetic field of the first magnetic layer is generated, “0”, “0”,
Digital data "1" can be recorded.

(Embodiment 10) The reproduction of magnetization information is perpendicular to the magnetic thin film memory element of the present invention, that is, in the order of the first magnetic layer, the nonmagnetic layer, the second magnetic layer, or the second magnetic layer. By measuring the resistance value between the first magnetic layer and the second magnetic layer of the memory element while flowing in the order of the nonmagnetic layer and the first magnetic layer, the magnetization information of “0” and “1” is detected. At this time, when the magnetization directions of the first magnetic layer and the second magnetic layer are parallel, the resistance value is small, and when the magnetization directions are antiparallel, the resistance value is large. Since the magnetization of the second magnetic layer is fixed in a predetermined direction, the resistance value differs depending on the magnetization recorded on the first magnetic layer, so that information can be read.

(Embodiment 11) The magnetic layer is not limited to a columnar shape.
Even in a structure having a square cross section, the magnetization may be oriented to the closed magnetic path. For example, instead of FIG.
(B) Instead of FIG. 3, a structure having a square cross section as shown in FIG. 10 (b) may be used. In FIG. 10, 1 is a first magnetic layer, 2 is a second magnetic layer, 3 is a non-magnetic layer, 4 is an insulating film, and 5 is a write line. The shape is not limited to a square, but may be a polygon.
However, a cylindrical structure is more preferable because it becomes the most stable closed magnetic circuit structure.

Embodiment 12 In the above embodiments, the first magnetic layer having a low coercive force is used as a memory layer for storing information, and the second magnetic layer having a high coercive force is used as a layer having a constant magnetization direction (pin layer). However, the second magnetic layer may be a memory layer for storing information, and the first magnetic layer may be a detection layer for reading information from the second magnetic layer. This detection layer is provided for reversing the magnetization in both directions at the time of reproduction and detecting a resistance change occurring at that time.

In the structure of the detection layer / nonmagnetic layer / memory layer,
The coercive force of the second magnetic layer is 10 Oe or more and 50 Oe or less,
It is desirable that the coercive force of the magnetic layer be not less than 2 Oe and not more than half of the coercive force of the second magnetic layer.

(Embodiment 13) In the above embodiments, a memory element has been mainly described. However, as can be seen from the above description, the element of the present invention is characterized in that a high MR ratio can be realized even if it is miniaturized. . Therefore, the present invention is not limited to the memory element, and may be applied to, for example, a magnetic head of a hard disk, a magnetic sensor, and the like.

[0041]

According to the present invention, as described above, it is possible to realize high preservation of magnetization information, high integration and reliability. Furthermore, there is an effect that a stable reproducing can be performed, a manufacturing margin of the nonmagnetic layer is wide, a reproducing time is short, and a reproducing method with less noise can be realized.

[Brief description of the drawings]

FIGS. 1A and 1B are three-dimensional explanatory views of a magnetic thin film memory element according to an embodiment of the present invention.

FIGS. 2A and 2B are three-dimensional explanatory diagrams showing a magnetization state of a magnetic thin film memory element according to one embodiment of the present invention.

FIG. 3 is a three-dimensional explanatory view showing a magnetization state of the magnetic thin film memory element according to one embodiment of the present invention.

FIG. 4 is an explanatory structural sectional view of a magnetic thin film memory element according to an embodiment of the present invention.

FIG. 5 is an explanatory structural sectional view of a magnetic thin film memory element according to an embodiment of the present invention.

FIG. 6 is a three-dimensional explanatory view showing a magnetization state of the magnetic thin film memory element according to one embodiment of the present invention.

FIG. 7 is an explanatory sectional view of a magnetic thin film showing a conventional magnetic thin film memory using a giant magnetoresistance effect.

8A and 8C are diagrams showing a recording operation of a conventional magnetic thin film memory using the giant magnetoresistance effect, and FIGS. 8A and 8C are diagrams showing a time T response of a word current I, and FIGS. (d) is a diagram showing the magnetization state of the conventional magnetic thin film memory.

9A and 9B are diagrams showing a reproducing operation of a conventional magnetic thin film memory using a giant magnetoresistance effect, wherein FIG. 9A is a diagram showing a time T response of a word current I, and FIGS. FIG. 4 is a diagram showing a magnetization state of the magnetic thin film memory of FIG.

FIGS. 10A and 10B are three-dimensional explanatory views of a magnetic thin film memory element showing another example of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st magnetic layer 2 2nd magnetic layer 3 non-magnetic layer 4 insulator 5 conductor 6,7 word line 61,62 sense line 71,72 word line W word line S sense line I insulating layer HM hard magnetic film SM soft Magnetic film NM Non-magnetic film

Claims (13)

[Claims] 1. A first magnetic layer having a low coercive force with a closed magnetic circuit structure and a second magnetic layer having a high coercive force with a closed magnetic circuit structure are laminated on a substrate via a nonmagnetic layer made of an insulator. The first magnetic layer and the second magnetic layer have an easy axis counterclockwise or counterclockwise, and have different resistance values depending on the relative angles of the magnetization directions of the first and second magnetic layers. A magnetoresistive element. 2. A magnetic thin film memory element comprising the magnetoresistive element according to claim 1. 3. The first magnetic layer and the second magnetic layer are made of Fe, C
2. The magnetic thin film memory element according to claim 1, wherein said magnetic thin film memory element contains at least one element of o and Ni. 4. The magnetoresistive element according to claim 1, wherein said nonmagnetic layer is made of aluminum oxide, aluminum nitride, silicon oxide, or silicon nitride. 5. The film thickness of the first magnetic layer and the second magnetic layer is 10
2. The magnetoresistive element according to claim 1, wherein the magnetic resistance is more than 0 angstroms and not more than 5000 angstroms. 6. The magnetoresistive element according to claim 1, wherein said nonmagnetic layer has a thickness of not less than 5 angstroms and not more than 30 angstroms. 7. The coercive force of the first magnetic layer is less than half the coercive force of the second magnetic layer, and the coercive force of the first magnetic layer is 100
2. The magnetoresistive element according to claim 1, wherein the coercive force of the second magnetic layer is greater than or equal to 50 Oe and less than or equal to 50 Oe. 8. An antiferromagnetic layer is provided in contact with a surface of the second magnetic layer opposite to the nonmagnetic layer, and the antiferromagnetic layer and the second magnetic layer are exchange-coupled to each other. 2. The magnetoresistive element according to claim 1, wherein the magnetization of the two magnetic layers is fixed. 9. The magnetoresistive element according to claim 1, wherein a conductor surrounded by an insulator is formed at the center of the first magnetic layer and the second magnetic layer. 10. The magnet according to claim 1, wherein the coercive force of the second magnetic layer is 10 Oe or more and 50 Oe or less, and the coercive force of the first magnetic layer is 2 Oe or more and half or less of the coercive force of the second magnetic layer. Resistance element. 11. A state where "0" and "1" are recorded by applying a current to said magnetic thin film memory element perpendicular to the film surface and determining a magnetization direction of said first magnetic layer by a magnetic field generated by said current. A recording method for a magnetic thin film memory, comprising: 12. Recording "0" and "1" states by applying a current to said magnetic thin film memory element perpendicular to the film surface and determining the magnetization direction of said second magnetic layer by a magnetic field generated by said current. A recording method for a magnetic thin film memory device, comprising: 13. A reproducing method for a magnetic thin film memory, characterized in that a current is applied to the magnetic thin film memory element in a direction perpendicular to the film surface and the resistance is measured to detect magnetization information of “0” and “1”.