JP4413603B2 - Magnetic storage device and magnetic information writing method - Google Patents

Description

  The present invention relates to a magnetic memory device for reversing the magnetization direction of a magnetization free layer by energizing a current in the plane and a method for writing magnetic information therefor.

  In recent years, development of a magnetic random access memory (MRAM) has been started that does not require power for holding stored information and can be rewritten virtually infinitely.

  A tunnel magnetoresistive element (TMR element) is used for an MRAM memory cell. Methods for writing magnetic information to the TMR element include a current magnetic field method and a spin injection method. In the current magnetic field method, current is passed through word lines and bit lines provided in the vicinity of a memory cell, and the magnetization of the magnetic layer of the TMR element is reversed and stored by a magnetic field generated by the current. The biggest problem with this method is that the write current per memory cell is large. If the write current is large, the wiring may be disconnected due to electromigration, or the area of the current drive circuit may increase and the chip area may increase.

  Therefore, as a technique for effectively utilizing the magnetic field generated by the wiring layer, there is a method of shortening the distance between the TMR element and the writing word line or using a magnetic flux concentration structure in which the wiring used for writing is covered with a high-permeability ferromagnetic thin film. Has been developed.

  However, the current magnetic field method has a problem that the current value required for writing to the memory cell rapidly increases as the element is miniaturized for higher density. In addition, since the distance between adjacent cells is shortened, there is a problem that crosstalk occurs due to a magnetic field.

  Therefore, a memory cell rewriting technique based on a spin injection method in which such a crosstalk problem does not occur and the write current does not increase even if the memory cell is miniaturized has been studied. The spin injection method is a method of reversing the magnetization of a magnetic layer by a current passed through the element (refer to Non-Patent Document 1 for a GMR element using a metal spacer instead of a tunnel insulating layer).

In order to cause magnetization reversal by the spin injection method, a constant current density is required, and the write current can be reduced as the element becomes finer. Therefore, the peripheral circuit area can be reduced, and the cost can be reduced by miniaturization. However, at a current density required for magnetization reversal, the tunnel barrier layer (tunnel insulating layer) of the TMR element and the memory cell isolation selection transistor may be destroyed. Therefore, it is desirable to reduce the current density required for magnetization reversal by one digit or more from the current level of about 5 × 10 ⁷ A / cm ² .
Phys. Rev. Lett. Vol. 84, No. 14, pp 3149-3152 (2000).

  The MRAM has an excellent characteristic that it does not require electric power for storing and can be rewritten infinitely. However, in the conventional spin injection method, the tunnel insulating layer and the isolation selection transistor may be destroyed due to the current density required for magnetization reversal.

  An object of the present invention is to provide a magnetic memory device capable of writing with a small current.

  The first aspect of the present invention is a conductive magnetization fixed layer provided with fixed magnetization, a tunnel insulating layer stacked on the magnetization fixed layer, and a junction formed on the magnetization fixed layer via the tunnel insulating layer. Conductive magnetization free comprising a domain wall pinning portion formed adjacent to a pair of end portions of a joint portion and a pair of magnetization fixed portions provided with opposite fixed magnetizations adjacent to the domain wall pinning portion A layer, and a pair of magnetic information writing terminals that are electrically connected to the pair of magnetization fixed portions and flow a current passing through the bonding portion, the pair of domain wall pinning portions, and the pair of magnetization fixed portions to the magnetization free layer. A magnetic storage device is provided.

The second aspect of the present invention is a magnetization fixed layer in which magnetization is fixed, a tunnel insulating layer stacked on the magnetization fixed layer, and a junction formed by stacking on the magnetization fixed layer via the tunnel insulating layer. A magnetic domain wall pinning portion formed adjacent to the pair of end portions of the joint, and a pair of magnetization fixed portions provided with fixed magnetizations in opposite directions adjacent to the domain wall pinning portion. To electrically connect the magnetization free layer and the pair of magnetization fixed portions, and to pass a current passing through the junction portion, the pair of domain wall pinning portions, and the pair of magnetization fixed portions of the magnetization free layer to the magnetization free layer Magnetic information writing method, comprising: a magnetoresistive effect element including a pair of magnetic information writing terminals, wherein a current flows only in the magnetization free layer to reverse the magnetization direction of the magnetization free layer. I will provide a.

  According to the present invention, since the magnetization of the magnetization free layer can be reversed with a small current, writing with a low current is possible. In addition, according to the present invention, it is possible to provide a magnetic storage device and a magnetization reversal method that have a high degree of integration and a low crosstalk.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol shall be attached | subjected to a common structure through embodiment and an Example, and the overlapping description is abbreviate | omitted. In addition, each of the drawings to be referred to is a schematic diagram for promoting explanation and understanding of the invention, and for convenience of display of the drawing, there are places where shapes, dimensions, ratios, and the like are different from the actual device. The design can be changed as appropriate in consideration of known techniques.
(First embodiment)
A first embodiment relating to a magnetic memory device and a magnetic information writing method of the present invention will be described with reference to the memory cell circuit diagram of FIG. 1 (however, only a cross-sectional schematic diagram of a TMR element).

  There are various types of memory cell patterns of the magnetic storage device. Generally, a pattern in which a plurality of memory cells are arranged vertically and horizontally on a substrate is known. In this pattern, for example, memory cells adjacent in the vertical direction share the same word line, and memory cells adjacent in the horizontal direction share the bit line. Although the present embodiment will be described on the assumption of this pattern, the magnetic memory device and the magnetic information writing method of the present invention can be applied to other memory cell patterns.

  One memory cell includes a combination of a MIS (metal-insulator-semiconductor) type field effect transistor (FET) 1 and a TMR element 3. The gate electrode of the FET 1 is connected to the word line 5 and controlled by the word line 5. That is, when magnetic information is written to or read from the memory cell, an ON voltage is applied from the word line to the gate electrode, and the FET 1 has a conductive state (ON state) between the source and drain electrodes.

  Since one of the source / drain electrodes of the FET 1 is connected to the plate electrode and the other source / drain electrode is connected to the TMR element 3, the conduction between the plate electrode and the TMR element 3 is established when the FET 1 is turned on. . In this conducting state, the tunnel junction resistance value of the TMR element 3 can be measured.

The TMR element 3 includes a magnetization fixed layer 31, a magnetization free layer 35, and a tunnel insulating layer 33 formed between both layers. A bit line (readout) 7 is connected to the magnetization fixed layer 31. When the plate electrode and the TMR element 3 become conductive, the resistance value of the TMR element 3 can be measured via the bit line 7 and the magnetic storage information can be read out. The tunnel junction resistance value is measured by a sense circuit connected to the end of the bit line 7. By reading the magnitude of the tunnel junction resistance value by this sense circuit, the magnetic storage information “1” or “0” stored in the TMR element 3 can be determined.

  A terminal of a bit line (write) 9 is connected to the other end of the magnetization free layer 35, and magnetic information can be written into the magnetization free layer 35 using this bit line 9. A method for writing the magnetic storage information will be described later.

  Next, the structure of the magnetization free layer 35 in the present embodiment will be described with reference to the schematic top view of FIG.

  The magnetization free layer 35 is composed of an integral ferromagnetic layer, and this ferromagnetic layer is divided into a tunnel junction 351, a pair of domain wall pinning portions 353, and a pair of magnetization fixed regions 357. In FIG. 2, the boundary between the tunnel junction portion 351 and the domain wall pinning portion 353 and the boundary between the domain wall pinning portion 353 and the magnetization fixed region 357 are indicated by dotted lines.

  The magnetization free layer 35 includes a domain wall 355 therein. The domain wall 355 extends in the direction perpendicular to the paper surface of FIG. 2, and is movable in the horizontal direction of the paper surface of FIG.

  The tunnel junction 351 forms a laminated body with the magnetization pinned layer 31 via the tunnel insulating layer 33, and this laminated body forms a tunnel junction of the TMR element 35.

  The pair of domain wall pinning portions 353 sandwich the tunnel junction portion 351 from the moving direction of the domain wall 355 in the magnetization free layer 35 (left and right direction in FIG. 2), and play a role of stopping the movement of the domain wall 355. In this embodiment, the movement of the domain wall 355 can be stopped by a wedge-shaped constriction (notch) 353 a formed on both side surfaces of the domain wall pinning portion 353 and extending in the in-plane direction. The pinning of the magnetic wall 355 by the constriction can be realized by a structure in which the width of the ferromagnetic layer is narrowed at both ends in the moving direction of the magnetic wall 355. The shape of the constriction may be a U shape in addition to the wedge shape. Further, the constriction need not be formed on both sides, and may be formed only on one side.

  The domain wall pinning structure other than the constriction includes a stress portion having crystal strain and a magnetic body portion having a high lattice defect density. Here, the lattice defects are vacancies, impurity doping, transition, and the like.

  A magnetization pinned portion 357 is formed outside the domain wall pinning portion 353 (on the extension of the moving direction of the domain wall 355 in the ferromagnetic layer). The position of the magnetization fixed portion can be changed as appropriate, for example, by laminating and forming a side wall of the domain wall pinning portion 353 (on the same plane) or above and below the domain wall pinning portion 353.

  The magnetization fixed unit 357 includes fixed magnetizations 357a and 357b fixed by an exchange bias or the like. Any one of the fixed magnetizations 357 a and 357 b is preferably parallel to the fixed magnetization of the magnetization fixed layer 31. The directions of the fixed magnetizations 357a and 357b are opposite to each other, thereby facilitating introduction of the domain wall 355 in the magnetization free layer 35 and shortening the moving distance of the domain wall 355. Is possible.

  In FIG. 2, the fixed magnetization 357a faces right and the fixed magnetization 357b faces left, but the relative angle between the two fixed magnetizations 357a and 357b may be approximately 180 °, and the orientation can be changed as appropriate. For example, the two magnetization directions may be upward / downward in FIG. 2, the magnetization of the left magnetization fixing unit 357 may be left, and the magnetization of the right magnetization fixing unit 357 may be right.

  The fixed magnetizations 357a and 357b can be fixed by an exchange bias due to exchange coupling with an adjacent antiferromagnetic layer, or a leakage magnetic field from a hard magnetic layer. The antiferromagnetic layer can also be laminated on the magnetization fixed portion 357. The hard magnetic layer can be laminated on the magnetization pinned portion 357, can be formed adjacent in the plane, or can be arranged in the vicinity of the plane.

  The direction of magnetization in the tunnel junction 351 can be changed by a current flowing from one end of the magnetization free layer 35 to multiple ends from the bit line 9. Due to the change in the magnetization direction of the magnetization free layer 35, magnetic information can be stored in the magnetization free layer 35.

  Next, an example of a method for writing the stored information will be described.

  First, as an initial state, for example, a portion on the left side of the domain wall 355 of FIG. 2 has a rightward magnetization 351a (magnetization in the same direction as the fixed magnetization 357a of the magnetization fixed portion 357), and a portion on the right side of the domain wall 355 has a leftward magnetization 351b It is assumed that the magnetization fixed portion 357 has magnetization in the same direction as the fixed magnetization 357b.

  When a write current is passed through the TMR element 3, the domain wall 355 is moved from the left side to the right domain wall pinning portion 353 by the current flowing through the magnetization free layer 35 (current flowing from right to left in the plane of FIG. 2). Can do. By the movement of the domain wall 355, the magnetization of the junction 351 can be reversed in the same direction as the fixed magnetization 357b of the right magnetization fixed unit 357.

  On the other hand, the domain wall pinned to the right constricted portion 353a is moved to the left by passing a current from left to right in the plane of FIG. As a result, the magnetization of the bonding portion 351 is directed rightward, which is equal to the fixed magnetization 357a of the left magnetization fixed portion 357.

  According to the domain wall motion method by energization in such a magnetization free layer, the current density required for the movement of the domain wall 355 is almost the same as the magnetization reversal by the spin injection method from the magnetization fixed layer. Since the sectional area of 35 can be made smaller than the tunnel junction area, the absolute value of the required write current is smaller in the domain wall motion method.

For example, when the plane area of the tunnel junction is about 100 × 100 nm ² and the thickness of the magnetization free layer is about 10 nm, the cross-sectional area of the free layer is about 1/10 of the junction area. Therefore, the absolute value of the necessary current is about 1/10 of the spin injection method, and the power consumption proportional to the square of the current can be about 1/100.

The junction resistance of the tunnel junction is about 10 Ωμm ² even at the lowest junction. When a current of 10 ⁷ to 10 ⁸ A / cm ² (0.1 to 1 A / μm ² ) is passed through the tunnel junction, the junction resistance is 0.1 to 10 W. / Μm ² of heat is generated. Since the heat generated by a general tunnel junction is about 1 mW / μm ² , the current value needs to be about 10 ⁶ A / cm ² or less in order to reverse the magnetization by the spin injection method. That is, it is necessary to perform magnetization reversal at a current value that is one digit lower than that at present, and it is considered difficult to realize with the conventional spin injection method.

On the other hand, in the domain wall motion method according to the present embodiment, the resistivity of the magnetization free layer 35 is about 10 ⁻⁵ Ωcm, and the contact resistance between the ferromagnetic magnetization free layer 35 and the metallic bit line 9 is about 5 ×. Since it is about 10 ⁻¹² Ωcm ^{2, when} the length of the magnetization free layer is about 200 nm and the area of the cross section substantially perpendicular to the moving direction of the domain wall 355 is about 100 × 10 nm ² , about 10 ⁷ to 10 ⁸ A / cm ^2. Even when a current of 1 mm is applied, the heat generation is about 0.2 μW to 20 μW (10 μW / cm ^{2 to 1} mW / cm ² ), and the magnetization can be reversed without destroying the tunnel junction.

  The force that the current exerts on the domain wall 355 depends on the mean free path of electrons and the thickness of the domain wall 355, and it is considered that a stronger moving force is exerted when the domain wall 355 is thinner than the mean free path of electrons. Since the mean free path in the ferromagnet is about 10 nm, the thickness of the domain wall is preferably about 10 nm or less.

  Since the thickness of the domain wall 355 decreases as the anisotropic energy increases, it is important to increase the anisotropic energy of the magnetization free layer 35 in order to promote the movement of the domain wall. In order to increase the anisotropy energy, the rare earth ions having high anisotropy energy such as Ce, Pr, Nd, and Sm are doped into the junction 351 of the magnetization free layer 35 or the junction 351 and the domain wall pinning portion 353. Is desirable.

  Here, as the magnetization free layer 35, Fe, Co, Ni, an alloy containing at least one of these, or other ferromagnetic materials can be used.

The tunnel insulating layer 33 can be made of a dielectric material such as AlO _x , MgO, HfO, AlHfN, AlN, AlHfO.

  For the magnetization fixed layer 31, Fe, Co, Ni, an alloy containing at least one of these, or other ferromagnetic materials can be used.

  For the antiferromagnetic layer, IrMn, PtMn, PdMn, RuRhMn, and other antiferromagnetic materials can be used.

  For the hard magnetic layer, FeC, CoNiAl, SmCo, NdFeB, or other hard magnetic materials can be used.

  As a material for the word line 5 and the bit lines 7 and 9, metallic materials such as Cu, Al, Au, and W can be used.

  As described above, according to the magnetic memory device and the magnetic information writing method according to the present embodiment, the magnetization reversal can be performed by the current regardless of the external magnetic field, and this current does not flow across the tunnel junction. Since only the magnetization free layer 35 flows, the power consumption can be reduced and the tunnel junction and the FET can be prevented from being broken. In addition, the current required for writing can be reduced as compared with spin injection using a tunnel junction, which contributes to low power consumption and high integration.

Example 1
A TMR element was created for the magnetic memory device according to the first embodiment of the present invention.

  A TMR element shown in the schematic side view of FIG. 3 was formed on a Si substrate using an ion beam sputtering apparatus and an electron beam lithography apparatus.

The TMR element 3 includes a Co magnetization fixed layer 31, an AlO _x tunnel insulating layer 33, and a Co magnetization free layer 35. A tunnel junction was formed by a laminate of the junction 351 of the magnetization free layer 35, the tunnel insulating layer 33, and the magnetization fixed layer 31. In place of the Si substrate, a glass substrate, an Al ₂ O ₃ .TiO _x substrate, or a ceramic substrate can be used. An underlayer for controlling the crystal structure of each layer of the TMR element 3 may be formed between the TMR element 3 and the Si substrate.

The tunnel junction extends in a direction (width: 200 nm) perpendicular to the paper surface of FIG. 3 and a horizontal direction (length: 400 nm) of the paper surface, and has an area of about 200 × 400 nm ² . The magnetization fixed layer 31 and the magnetization free layer 35 have a width of about 200 nm and a thickness of about 20 nm. The length of the magnetization fixed layer 31 is about 400 nm. The length of the magnetization free layer 35 is about 1200 nm.

The tunnel insulating layer 33 is made of AlO _x . This AlO _x layer was formed by plasma oxidizing the Al layer formed on the magnetization free layer 35. The tunnel insulating layer AlO _{x had} a width of about 200 nm, a length of about 400 nm, and a thickness of about 1 nm.

  Two wedge-shaped constrictions 353a are formed on the pair of domain wall pinning portions 353 of the magnetization free layer 35, respectively. In FIG. 3, the constrictions 353a (two) on one side are shown. The constriction 353a was formed by electron beam lithography and ion milling after the formation of the magnetization free layer. The width of the wedge-shaped constriction 353a on the side surface of the magnetization free layer 35 and the depth from the side surface were about 50 nm.

  On the pair of magnetization fixed portions 357 and the magnetization fixed layer 31 of the magnetization free layer 35, antiferromagnetic (IrMn) layers 11a, 11b, and 11c having a thickness of about 100 nm are formed. The fixed layer 31 and the magnetization fixed portion 357 were magnetically exchange coupled. By this magnetic exchange coupling, an exchange bias of a predetermined direction is applied to the magnetization fixed layer 31 and the magnetization fixed portion 357, the fixed magnetization 31a is applied to the magnetization fixed layer 31, and the fixed magnetization 357a is provided on the left side of the pair of magnetization fixed portions 357. On the right side, fixed magnetization 357b was given. This exchange coupling was introduced by forming each IrMn layer in a magnetic field oriented in each magnetization direction (the strength of the magnetic field was about 2000 Oe).

  A read Au electrode 13 was formed on the antiferromagnetic layer 11c. Further, a pair of writing Au electrodes 15 was formed on the pair of magnetization fixed portions 357 of the magnetization free layer 35.

  Next, magnetic information was written to and read from the TMR element 3.

  First, a current was passed through one of the Au electrode 13 and the Au electrode 15 under the external magnetic field H, and the magnetoresistance effect of the tunnel junction was measured. The result is shown in the current (mA) -tunnel junction resistance (Ω) characteristic diagram of FIG. The positive and negative of the magnetic field H is positive in the right direction and negative in the left direction in FIG.

A magnetic field of −100 Oe was applied to the TMR element 3 so that the magnetization of the magnetization free layer 35 was parallel to the magnetization 31 a of the magnetization fixed layer 31. Thereafter, the magnetic field was gradually changed to a positive magnetic field (100 Oe), and the resistance of the TMR element 3 was measured. The tunnel junction resistance of the TMR element 3 increases at about 40 Oe. At this stage, the magnetization of the magnetization free layer 35 is reversed, and the two magnetizations of the magnetization fixed layer 31 and the magnetization free layer 35 become antiparallel. I understand that. The specific resistance of the tunnel junction was about 100 Ωμm ² and the MR ratio was about 10%.

  Thereafter, even when the external magnetic field H is returned to zero, the tunnel junction resistance is maintained in a high resistance state. Therefore, it is considered that the domain wall 355 is trapped (trapped) by the domain wall pinning portion 353a on the right side of FIG. Subsequently, the following measurement was performed with the external magnetic field H being zero.

  First, a current in a positive direction (rightward in FIG. 2) was passed between the left and right Au electrodes 15 for 1 msec, and then the tunnel junction resistance was measured after returning the current to zero. The positive current causes electrons to flow to the left. The same measurement was repeated by gradually increasing the current value. The result is shown in the current (mA) -tunnel junction resistance (Ω) characteristic diagram of FIG.

The tunnel junction resistance changed from a high resistance state to a low resistance state at a current of about 1.9 mA, and the domain wall was moved from the right domain wall pinning portion 353 to the left domain wall pinning portion 353 by this magnitude of current. I understand. When a current of about 1.9 mA is converted into a current density, it is about 4.8 × 10 ⁷ A / cm ² .

When the same layer as the magnetization free layer 35 according to the present example was formed and the domain wall was observed with an MFM (Magnetic Force Microscope), the domain wall width was about 30 nm.
(Example 2)
A tunnel junction including a Co magnetization fixed layer 31, an AlO _x tunnel insulating layer 33, and a CoSm _x magnetization free layer 35 was fabricated in the same manner as in Example 1.

In this embodiment, the magnetization free layer 35, using CoSm _x alloy about 5% of Sm in place of the Co doped. Other layer materials and the structure of the TMR element 3 are the same as those in the first embodiment.

  With respect to the resistance (Ω) of the tunnel junction, the correlation characteristics of the external magnetic field (Oe) and current (mA) and the tunnel junction resistance (Ω) were measured. The results are shown in FIGS.

  In FIG. 6, the magnetic field in which the tunnel junction resistance changes is increased compared to FIG. 4, and the resistance changes at about 70 Oe. This is considered to be because the coercive force of the magnetization free layer 35 is increased by the addition of Sm.

On the other hand, in FIG. 7, the current at which the tunnel junction resistance changes is reduced as compared with FIG. 5, and the current is changed from the high resistance state to the low resistance state at a current of about 1.3 mA (current density is 3.2 × 10 ⁷ A / cm ² ). You can see that it has changed.

  When the domain wall was observed by MFM for the same layer as the magnetization free layer of this example, the thickness was estimated to be about 10 nm. This shows that the magnetic anisotropy energy of the magnetization free layer 35 is increased by adding Sm, so that the domain wall width is reduced, and the force applied to the domain wall by the same amount of current is increased as compared with the first embodiment. ing.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a circuit diagram (partially cross-sectional schematic diagram) for explaining a first embodiment relating to a magnetic storage device and a magnetic information writing method of the present invention; The top view of the magnetization free layer in connection with 1st Embodiment. The cross-sectional schematic diagram which shows the TMR element of Example 1 in connection with 1st Embodiment. FIG. 4 is a characteristic diagram of the magnetic field (Oe) -tunnel junction resistance (Ω) of the TMR element according to Example 1; FIG. 6 is a characteristic diagram of current (mA) -tunnel junction resistance (Ω) of the TMR element according to Example 1; The magnetic field (Oe) -tunnel junction resistance (ohm) characteristic view by the TMR element of Example 2 in connection with 1st Embodiment. FIG. 10 is a characteristic diagram of current (mA) -tunnel junction resistance (Ω) of the TMR element according to Example 2.

Explanation of symbols

1 ... FET
3 ... TMR element 5 ... word line 7 ... bit line (read)
9: Bit line (write)
31 ... Magnetization fixed layer 33 ... Tunnel insulating layer 35 ... Magnetization free layer

Claims (10)

A conductive fixed magnetization layer provided with fixed magnetization;
A tunnel insulating layer laminated on the magnetization fixed layer;
A junction formed by laminating with the magnetization fixed layer via the tunnel insulating layer, a domain wall pinning portion formed adjacent to a pair of ends of the junction, and opposite directions adjacent to the domain wall pinning portion A conductive free magnetization layer comprising a pair of fixed magnetization portions provided with a fixed magnetization of
A pair of magnetic information that is electrically connected to the pair of magnetization fixed portions and causes a current passing through the joint portion of the magnetization free layer, the pair of domain wall pinning portions, and the pair of magnetization fixed portions to flow in the magnetization free layer. A magnetic storage device comprising a write terminal. The magnetic storage device according to claim 1, further comprising a constriction on a side portion of the domain wall pinning portion. 3. The magnetic storage device according to claim 1, wherein the magnetization free layer has a domain wall therein, and the magnetization free layer is made of a material whose thickness is smaller than an average free path of electrons. . 4. The magnetic memory device according to claim 1, wherein the thickness of the domain wall in the magnetization free layer is 10 nm or less. 5. The magnetic storage device according to claim 1, wherein the magnetic material of the magnetization free layer contains a rare earth element. A tunnel magnetoresistive effect element including the magnetization fixed layer, the tunnel insulating layer, and the magnetization free layer, and a field effect transistor electrically connected to the tunnel magnetoresistive effect element through one of the pair of magnetic information write terminals The magnetic storage device according to claim 1, further comprising: The field effect transistor has a gate electrode and a pair of source / drain regions, one of the pair of source / drain regions is electrically connected to the tunnel magnetoresistive element, and the other of the pair of source / drain regions is a plate. 7. The magnetic memory device according to claim 6, wherein one magnetic memory cell is constituted by a combination of the field effect transistor and the tunnel junction element connected to an electrode. 8. The magnetic memory device according to claim 7, wherein a plurality of the memory cells are formed on the same substrate to form a memory cell matrix. 2. The cross-sectional area of a portion through which the current flows in the junction of the magnetization free layer is smaller than a junction area facing the magnetization fixed layer through the tunnel insulating layer of the junction. The magnetic storage device according to any one of 1 to 8. Magnetization fixed layer with fixed magnetization, tunnel insulating layer stacked on the magnetization fixed layer, a junction formed by lamination with the magnetization fixed layer via the tunnel insulation layer, and a pair of ends of the junction A magnetic domain wall pinning portion formed adjacent to each other, a pair of magnetization free layers having a pair of magnetization fixed portions adjacent to the domain wall pinning portion and provided with fixed magnetizations in opposite directions, and the pair of magnetizations A pair of magnetic information writing terminals electrically connected to the fixed portion and for causing a current passing through the joint portion of the magnetization free layer, the pair of domain wall pinning portions, and the pair of magnetization fixed portions to flow in the magnetization free layer; A magnetic information writing method, wherein a current is passed only in the magnetization free layer to reverse the magnetization direction of the magnetization free layer.

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