Rail memory device

Abstract

The racetrack memory device may include: a write element extending in a first horizontal direction and configured to generate a magnetic domain based on a first current applied to the write element; a moving element having a first end connected to the write element and extending in a second horizontal direction intersecting the first horizontal direction, the moving element configured to inject a magnetic domain generated in the write element into the moving element based on a second current applied to the moving element; and a reading element on the moving element and configured to read a magnetic domain included in the moving element. A width of the moving element may be less than a width of the writing element.

Description

[0001] Cross - reference to related applications

[0002] This disclosure claims the benefit of Korean Patent Application No. 10 - 2024 - 005031, filed on January 11, 2024, with the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. Technical field

[0003] This disclosure relates to a magnetic memory device, and more particularly, to a racetrack memory device. Background art

[0004] A racetrack memory device can use magnetic domains as memory cells and can store information as 1s and 0s according to the direction of the magnetic domains. In a racetrack device, the direction of movement of the magnetic domains within the racetrack changes according to the direction of current flow. Since the movement speed of the magnetic domains is very fast and the size of the magnetic domains is small, the racetrack device has attracted attention as an ultra - fast, high - capacity memory device.

[0005] A racetrack memory device can include a writing element, a moving element, and a reading element. To drive a racetrack memory device with high density and low power consumption, it is necessary to record magnetic domains with small energy or control the size of magnetic domains. Summary of the invention

[0006] Provided is a racetrack memory device in which a writing element that generates magnetic domains and a moving element that moves magnetic domains are spatially separated from each other.

[0007] Provided is a racetrack memory device that can generate magnetic domains without an external magnetic field.

[0008] Provided is a racetrack memory device that can move magnetic domains without an external magnetic field.

[0009] Additional aspects will be set forth in part in the description that follows and, in part, will be obvious from the description, or may be learned by practice of the presented embodiments.

[0010] According to an exemplary embodiment of the present disclosure, a racetrack memory device may include: a write element that extends in a first horizontal direction and is configured to generate magnetic domains based on a first current applied to the write element; a move element having a first end connected to the write element, the move element extending in a second horizontal direction that intersects the first horizontal direction, the move element being configured to inject the magnetic domains generated in the write element into the move element based on a second current applied to the move element; and a read element that is on the move element and is configured to read the magnetic domains included in the move element. The width of the move element may be less than the width of the write element.

[0011] In some embodiments, the ratio of the width of the write element to the width of the move element may be 1.5 or greater.

[0012] In some embodiments, the ratio of the width of the write element to the width of the move element may be 5 or less.

[0013] In some embodiments, the ratio of the length of the write element to the width of the move element may be 2 or greater.

[0014] In some embodiments, the write element may be configured to generate magnetic domains having a magnetization direction corresponding to the direction of the first current.

[0015] In some embodiments, the write element may be configured to generate the magnetic domains such that if the direction of the first current applied to the write element is parallel to the first horizontal direction, then the magnetic domains have a first magnetization direction, and the write element may be configured to generate the magnetic domains such that if the direction of the first current applied to the write element is opposite to the first horizontal direction, then the magnetic domains have a second magnetization direction. The second magnetization direction may be opposite to the first magnetization direction.

[0016] In some embodiments, if a first magnetic domain having the first magnetization direction is already in the write element, then the write element may be configured to change the magnetic domain in the write element from the first magnetic domain to a second magnetic domain having the second magnetization direction if the direction of the first current applied to the write element is opposite to the first horizontal direction.

[0017] In some embodiments, the size of the magnetic domains injected into the move element may be based on the pulse width of the second current.

[0018] In some embodiments, the size of the magnetic domains injected into the move element may be proportional to the pulse width of the second current.

[0019] In some embodiments, the intensity of the second current may be less than or equal to the intensity of the first current.

[0020] In some embodiments, the intensity of the second current may be 1 / 3 or less of the intensity of the first current.

[0021] In some embodiments, the pulse width of the first current and the pulse width of the second current may be equal.

[0022] In some embodiments, the racetrack memory device may further include a first electrode at a first end of the write element; a second electrode at a second end of the write element, the second end of the write element being opposite to the first end of the write element; and a third electrode connected to the second end of the mobile element, the second end of the mobile element being different from the first end of the mobile element.

[0023] In some embodiments, the racetrack memory device may be configured to apply the first current through the first electrode and the second electrode, and the racetrack memory device may be configured to apply the second current through the third electrode when the first electrode and the second electrode are grounded.

[0024] In some embodiments, the write element may include a first spin-orbit torque layer configured to induce a first spin-orbit torque based on the first current, a first free layer on the first spin-orbit torque layer and configured to generate magnetic domains based on the first spin-orbit torque, a first oxide layer on the first free layer, an insulating layer on the first oxide layer, and a magnetic hard mask configured to form a magnetic field in an effective horizontal direction in the first free layer. The mobile element may include: a second spin-orbit torque layer configured to induce a second spin-orbit torque through the second current, the second spin-orbit torque layer corresponding to the first spin-orbit torque layer; a second free layer on the second spin-orbit torque layer, the mobile element being configured to inject magnetic domains into the second free layer based on the second spin-orbit torque; and a second oxide layer on the second free layer.

[0025] In some embodiments, the magnetic hard mask may be on the insulating layer.

[0026] In some embodiments, the magnetic hard mask may overlap the first free layer in a vertical direction and may not overlap the second free layer, and the vertical direction may intersect the first horizontal direction and the second horizontal direction.

[0027] In some embodiments, the magnetic hard mask may include a first magnetic hard mask and a second magnetic hard mask separated from each other in a first horizontal direction.

[0028] In some embodiments, the magnetic hard mask may overlap with the first free layer in a vertical direction intersecting the first horizontal direction and the second horizontal direction and may not overlap with the second free layer.

[0029] In some embodiments, the write element may include a first ferromagnetic layer having horizontal magnetic anisotropy, a first spin-orbit torque layer on the first ferromagnetic layer and configured to induce a first spin-orbit torque based on a first current, and a first free layer on the first spin-orbit torque layer and configured to generate magnetic domains based on the first spin-orbit torque. The mobile element may include a second ferromagnetic layer in the same plane as the first ferromagnetic layer, a second spin-orbit torque layer on the second ferromagnetic layer and configured to induce a second spin-orbit torque, and a second free layer on the second spin-orbit torque layer, the mobile element being configured to inject magnetic domains into the second free layer based on the second spin-orbit torque.

[0030] In some embodiments, the write element may include a first antiferromagnetic layer and a first free layer, the first antiferromagnetic layer being configured to generate a first spin current using an exchange bias field based on a first current, and the first free layer on the first antiferromagnetic layer and configured to generate magnetic domains using the exchange bias field based on the first spin current. The mobile element may include a second antiferromagnetic layer and a second free layer, the second antiferromagnetic layer being in the same plane as the first antiferromagnetic layer and configured to generate a second spin current based on a second current, and the second free layer on the second antiferromagnetic layer, the mobile element being configured to inject magnetic domains into the second free layer based on the second spin current. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] These and / or other aspects will become apparent and more readily understood from the following description of embodiments in conjunction with the accompanying drawings, in which:

[0032] Figure 1 is a schematic plan view of a racetrack memory device according to an embodiment;

[0033] Figure 2 is Figure 1 a cross-sectional view of a write element of the racetrack memory device;

[0034] Figure 3 is Figure 1 a schematic perspective view of the racetrack memory device;

[0035] Figure 4A is a reference diagram for describing a method of generating magnetic domains according to the direction of current in a write element according to an embodiment;

[0036] Figure 4B is a reference diagram for describing a method of generating magnetic domains according to the direction of current in a write element according to an embodiment;

[0037] Figures 5A to 5D Shows measurement results of the size of magnetic domains according to the pulse width of a second current according to an embodiment;

[0038] Figures 6A to 6E Is a reference diagram for describing the operation of a racetrack memory device according to an embodiment;

[0039] Figure 7A Is a cross-sectional view of a part of a racetrack memory device including a plurality of magnetic hard masks according to another embodiment;

[0040] Figure 7B Is Figure 7A A plan view of a part of the racetrack memory device;

[0041] Figure 8 Is a cross-sectional view of a write element according to another embodiment;

[0042] Figure 9 Is including Figure 8 A perspective view of a racetrack memory device including the write element;

[0043] Figure 10 Is a cross-sectional view of a write element according to another embodiment;

[0044] Figure 11 Is including Figure 10 A perspective view of a racetrack memory device including the write element;

[0045] Figure 12 Is a schematic perspective view of a memory cell including a racetrack memory device according to an embodiment;

[0046] Figure 13 Is schematically showing including a plurality of Figure 12 A circuit diagram of the configuration of a memory device including memory cells; and

[0047] Figure 14 Is a conceptual diagram schematically showing a device architecture applicable to an electronic device according to an embodiment. Detailed Description

[0048] Now, embodiments will be described in detail, examples of which are shown in the drawings, where the same reference numerals always denote the same elements, and for ease of explanation and clarity, the sizes of components in the drawings may be exaggerated. In this regard, embodiments may have different forms and should not be construed as limited to the descriptions set forth herein. Thus, the embodiments are described below only by reference to the drawings to explain various aspects. Since the embodiments described below are examples, other modifications may be derived from the embodiments.

[0049] Expressions such as "at least one of..." when preceding a list of elements modify the entire list of elements, rather than each individual element in the list. For example, "at least one of A, B, and C" and similar language (e.g., "selected from at least one of the group consisting of A, B, and C") can be interpreted to mean only A, only B, only C, or any combination of two or more of A, B, and C, such as ABC, AB, BC, and AC.

[0050] When the terms "about" or "substantially" are used in this specification in connection with a numerical value, it is intended that the associated numerical value include the manufacturing or operating tolerances around the stated value (e.g., ±10%). In addition, when the words "substantially" and "about" are used in connection with a geometric shape, it is intended that the precision of the geometric shape is not required, but rather the tolerance of the shape is within the scope of the present disclosure. Further, whether a numerical value or shape is modified by "about" or "substantially", it should be understood that these values and shapes should be interpreted to include the manufacturing or operating tolerances around the stated numerical value or shape (e.g., ±10%). When a range is specified, the range includes all values therebetween, such as increments of 0.1%. Although the term "equal to" is used in the description of the exemplary embodiments, it should be understood that there may be some imprecision. Thus, when an element is referred to as "equal to" another element, it should be understood that within the desired manufacturing or operating tolerance range (e.g., ±10%), the element or value may be "equal to" another element.

[0051] When a constituent element is disposed "above" or "on" another constituent element, the constituent element may include not only an element that directly contacts the upper / lower / left / right side of the other constituent element, but also an element that is disposed above / below / left / right of the other constituent element in a non-contact manner. As used herein, the singular forms "a", "an", and "the" are intended to also include the plural forms unless the context clearly dictates otherwise. In addition, the terms "comprising" and / or "including" used herein specify the presence of the stated feature or component, but do not preclude the presence or addition of one or more other features or components.

[0052] In addition, unless otherwise stated herein or the context clearly contradicts, the operations of all methods described herein can be performed in any suitable order. The present disclosure is not limited to the order of the steps described.

[0053] In addition, terms such as "section", "unit", "module", and "block" stated in the specification may represent a unit for handling at least one function or operation, and the unit may be embodied by hardware, software, or a combination of hardware and software.

[0054] In addition, the connecting lines or connectors shown in the various figures presented are intended to represent the functional relationships and / or physical or logical couplings between the various elements.

[0055] It should be understood that although terms such as "first" and "second" may be used herein to describe various components, these components should not be limited by these terms. These terms are only used to distinguish one component from another.

[0056] Unless otherwise stated, the use of any and all examples or language (e.g., "such as") provided herein is only intended to better illustrate the present disclosure and does not limit the scope of the present disclosure.

[0057] Figure 1 is a plan view schematically showing a racetrack memory device 1 according to an embodiment, Figure 2 is Figure 1 a cross-sectional view of a write element 10 of the racetrack memory device 1, and Figure 3 is Figure 1 a schematic perspective view of the racetrack memory device 1.

[0058] Referring to Figures 1 to 3 , the racetrack memory device 1 may include a write element 10 that generates magnetic domains based on a first current applied thereto, a moving element 20 that injects magnetic domains generated in the write element 10 or moves the injected magnetic domains therein based on a second current applied thereto, and a read element 30 that reads the magnetic domains included in the moving element 20.

[0059] The racetrack memory device 1 may include a first electrode E1 and a second electrode E2 respectively disposed at opposite ends of the write element 10, a third electrode E3 disposed at one end of the moving element 20, and a fourth electrode E4 disposed at one end of the read element 30. The write element 10 and the moving element 20 may be provided on the same substrate W, and the racetrack memory device 1 may further include a seed layer S.

[0060] A magnetic domain may be a region with a uniform magnetization direction, and a magnetic domain wall may be a region where the magnetization direction changes between magnetic domains in the moving element 20. Each magnetic domain wall may define a boundary between magnetic domains having different magnetization directions from each other.

[0061] The write element 10 may extend in a first horizontal direction (e.g., the Y direction) and generate magnetic domains based on a first current applied thereto. The write element 10 may generate magnetic domains through magnetization switching based on the first current. For example, the first current may be applied to the write element 10 through the first electrode E1 and the second electrode E2. The write element 10 may generate a first magnetic domain having a magnetization direction in the vertical direction (e.g., the +Z direction) or a second magnetic domain having a magnetization direction in a direction opposite to the vertical direction (e.g., the -Z direction) based on the direction of the first current. The first magnetic domain and the second magnetic domain may be referred to as the upper domain and the lower domain, respectively.

[0062] Whenever a magnetic domain having a magnetization direction opposite to that of the magnetic domain already generated in the write element 10 is generated, a first current can be applied to the write element 10. For example, when a magnetic domain having the same magnetization direction as that of the magnetic domain already generated in the write element 10 is to be generated, the first current may not be applied to the write element 10. Since the first current is applied to the write element 10 only when a magnetic domain is generated by magnetization switching, the power supplied to the write element 10 can be saved.

[0063] One end of the movable element 20 can be connected to the write element 10 and can extend in a second horizontal direction (e.g., the X direction) intersecting the first horizontal direction (e.g., the Y direction). The magnetic domain generated in the write element 10 can be injected into the movable element 20 based on a second current applied to the movable element 20, or in the movable element 20, the injected magnetic domain can move in the second horizontal direction (e.g., the X direction).

[0064] The movable element 20 can include a plurality of magnetic domains and a plurality of magnetic domain walls. The plurality of magnetic domains and the plurality of magnetic domain walls can be alternately or repeatedly arranged in the second horizontal direction (e.g., the X direction). The size and magnetization direction of each magnetic domain can be appropriately controlled by the shape, size, and second current of the movable element 20. The magnetic domain and / or the magnetic domain wall can be moved based on the second current applied to the movable element 20.

[0065] The second current can be applied to the movable element 20 through the first to third electrodes E1, E2, and E3. For example, the first electrode E1 and the second electrode E2 can be grounded, and the second current can be applied to the movable element 20 through the third electrode E3. The second current can be in the form of a pulse. The movable element 20 can inject the magnetic domain generated in the write element 10 into the movable element 20 based on the second current, or move the magnetic domain included in the movable element 20. The size of the magnetic domain can be proportional to the pulse width of the second current.

[0066] The read element 30 can read the magnetic domain included in the movable element 20. For example, the first to third electrodes E1, E2, and E3 are grounded, and the third current can be applied to the read element 30 through the fourth electrode E4. The read element 30 can read the magnetic domain included in the region overlapping the read element 30 in the movable element 20 based on the third current.

[0067] In the racetrack memory device 1 according to the embodiment, the write element 10 and the movable element 20 can be spatially separated from each other. Then, the magnetic domain can be easily stored in the movable element 20 by multiple bits.

[0068] The width W2 of the mobile element 20 can be smaller than the width W1 of the write element 10. As the cross-sectional size of the mobile element 20 in contact with the write element 10 increases, the edge pinning potential can increase accordingly. This is to limit and / or prevent magnetization switching from occurring in the write element 10. For example, the ratio of the width W1 of the write element 10 to the width W2 of the mobile element 20 can be about 1.5 or greater, 2 or greater, or 3 or greater.

[0069] When the ratio of the width W1 of the write element 10 to the width W2 of the mobile element 20 is too large, the cross-section of the racetrack memory device 1 increases, which may consume a large amount of power to operate the write element 10. Therefore, the ratio of the width W1 of the write element 10 to the width W2 of the mobile element 20 can be about 5 or smaller. In addition, the ratio of the length L1 of the write element 10 to the width W2 of the mobile element 20 can be about 2 or greater (e.g., 2 to 10 or greater). The ratio of the length L2 of the mobile element 20 to the length L1 of the write element 10 can be about 5 or greater.

[0070] Figure 2 is a cross-sectional view of the racetrack memory device 1 including Figure 1 the write element 10. Referring to Figure 2 , the write element 10 can include a first spin-orbit torque layer 110, a first free layer 120 disposed on the first spin-orbit torque layer 110, a first oxide layer 130 disposed on the first free layer 120, and an insulating layer 140 on the first oxide layer 130. The first electrode E1 and the second electrode E2 can be disposed at opposite ends of the write element 10, respectively. A first current can be applied to the first spin-orbit torque layer 110 and the first free layer 120 through the first electrode E1 and the second electrode E2.

[0071] The first spin-orbit torque layer 110 can induce a spin-orbit torque by the first current flowing therein. The first spin-orbit torque layer 110 can include a non-magnetic heavy metal having an atomic number of 30 or higher. For example, the first spin-orbit torque layer 110 can include at least one of iridium (Ir), ruthenium (Ru), tantalum (Ta), platinum (Pt), palladium (Pd), bismuth (Bi), titanium (Ti), tungsten (W), and their alloys, but the present disclosure is not limited thereto.

[0072] The first free layer 120 may be disposed on the first spin-orbit torque layer 110. The first free layer 120 may include a ferromagnet. For example, the first free layer 120 may include at least one of iron (Fe), cobalt (Co), nickel (Ni), manganese (Mn), Fe-containing alloys, Co-containing alloys, Ni-containing alloys, Mn-containing alloys, and Heusler alloys. Alternatively, the first free layer 120 may have a synthetic antiferromagnetic (SAF) structure. For example, the first free layer 120 may include (Co / Ni)n / Ru / (Co / Ni)n or (Co / Ni)n / Ir / (Co / Ni)n having a structure of magnetic layer / non-magnetic layer (Ru or Ir) / magnetic layer.

[0073] The first oxide layer 130 may be disposed on the first free layer 120. The first oxide layer 130 may include crystalline magnesium oxide. For example, the first oxide layer 130 may include at least one of MgO, Al2O3, NaCl, and ZnO. The thickness of the first oxide layer 130 may be about 1 nm to about 3 nm.

[0074] The insulating layer 140 may be disposed on the first oxide layer 130. The insulating layer 140 may include an insulating material such as SiO2.

[0075] The magnetic hard mask 150 may form a magnetic field in an effective horizontal direction (e.g., -Y direction) on the first free layer 120. The magnetic hard mask 150 may be disposed on the insulating layer 140.

[0076] The magnetic hard mask 150 may include a material having in-plane magnetic anisotropy, e.g., a ferromagnetic material including at least one of Fe, cobalt (Co), and Ni. The magnetic hard mask 150 may have a thickness greater than the thickness of the first free layer 120 to form a magnetic field having a sufficient magnitude. For example, the thickness of the magnetic hard mask 150 may be about 5 times or more, about 10 times or more, or about 30 times or less the thickness of the first free layer 120.

[0077] To form a magnetic field in an effective horizontal direction (e.g., -Y direction) on the first free layer 120, the magnetic hard mask 150 may be sufficiently separated from the first free layer 120. For example, the distance between the magnetic hard mask 150 and the first free layer 120 may be about 10 nm or greater, about 20 nm or greater, or about 30 nm or greater. However, when the distance between the magnetic hard mask 150 and the first free layer 120 is too large, the intensity of the magnetic field decreases, and thus, the distance between the magnetic hard mask 150 and the first free layer 120 may be about 100 nm or less or about 80 nm or less.

[0078] When the magnetic hard mask 150 is formed of Co to have a thickness of about 50 nm and the distance between the magnetic hard mask 150 and the first free layer 120 is about 30 nm, the magnetic hard mask 150 can generate an effective horizontal magnetic field of about 30 millitesla (mT) in the first free layer 120. A magnetic field in the effective horizontal direction (e.g., -Y direction) with the above intensity is uniformly formed in the first free layer 120 and is sufficient to perform magnetization switching in the first free layer 120 without injecting an external magnetic field.

[0079] When a magnetic field in the effective horizontal direction (e.g., -Y direction) is formed in the first free layer 120 through the magnetic hard mask 150, the magnetization direction of the first free layer 120 aligned in the vertical direction (e.g., Z direction) can be tilted in the horizontal direction (e.g., -Y direction) by the above magnetic field in the effective horizontal direction (e.g., -Y direction). In this tilted state, when a current flows in the first spin-orbit torque layer 110, a first spin current polarized in a specific direction is generated in the first spin-orbit torque layer 110, such that a corresponding first spin-orbit torque can be induced. When the magnetization direction of the first free layer 120 is rotated by the above first spin-orbit torque, magnetization switching occurs, such that magnetic domains can be generated. The generation of the above magnetic domains corresponds to the writing of magnetic domains.

[0080] Reference Figure 3 Referring to, the moving element 20 may include a second spin-orbit torque layer 210, a second free layer 220 disposed on the second spin-orbit torque layer 210, and a second oxide layer 230 disposed on the second free layer 220. One ends of the second spin-orbit torque layer 210, the second free layer 220, and the second oxide layer 230 may be in contact with the first spin-orbit torque layer 110, the first free layer 120, and the first oxide layer 130, respectively. The second spin-orbit torque layer 210, the second free layer 220, and the second oxide layer 230 may be integrally formed with the first spin-orbit torque layer 110, the first free layer 120, and the first oxide layer 130, respectively. Since the second spin-orbit torque layer 210, the second free layer 220, and the second oxide layer 230 respectively correspond to the first spin-orbit torque layer 110, the first free layer 120, and the first oxide layer 130 of the writing element 10, a detailed description thereof is omitted. The moving element 20 does not include the magnetic hard mask 150 included in the writing element 10. The racetrack memory device 1 may further include a third electrode E3 disposed at the other end of the moving element 20.

[0081] A second voltage can be applied to the writing element 10 and the moving element 20 through the first to third electrodes E1, E2, and E3. For example, the first electrode E1 and the second electrode E2 can be grounded, and the second voltage can be applied to the third electrode E3. A second current can flow in the first and second spin-orbit torque layers 110 and 210. Both the second voltage and the second current can be of a pulsed type. A spin current polarized in a specific direction can be generated in the first spin-orbit torque layer 110 and the second spin-orbit torque layer 210, and a second spin-orbit torque corresponding to the above spin current can be induced.

[0082] The torque in the second horizontal direction (e.g., the X direction) of the second spin-orbit torque can cause the magnetic domains included in the writing element 10 to move in the second horizontal direction (e.g., the X direction) and be injected into the moving element 20. In addition, the torque in the second horizontal direction (e.g., the X direction) of the second spin-orbit torque can move the magnetic domains included in the moving element 20 in the second horizontal direction (e.g., the X direction).

[0083] The movement range of the magnetic domains or the size of the magnetic domains can vary according to the pulse width of the second current. For example, as the pulse width of the second current decreases, the movement range of the magnetic domains or the size of the magnetic domains may decrease. Therefore, by applying a second current with a small pulse width to the writing element 10 and the moving element 20, a large number of magnetic domains can be stored in the moving element 20. To synchronize the first current with the second current, the pulse width of the first current can be the same as the pulse width of the second current.

[0084] The reading element 30 can include a third oxide layer 330 provided on the moving element 20 and a fixed layer 340 provided on the third oxide layer 330. In the racetrack memory device 1, the moving element 20 and the reading element 30 can be configured to form a magnetic tunnel junction (MTJ) structure.

[0085] The third oxide layer 330 can correspond to the first oxide layer 130 and the second oxide layer 230. For example, the first to third oxide layers 130, 230, and 330 can be integrally formed. The electrons included in the region of the moving element 20 that overlaps with the reading element 30 in the thickness direction of the moving element 20 can enter the fixed layer 340 through the quantum tunneling of the third oxide layer 330.

[0086] The fixed layer 340 may include a ferromagnetic material. The fixed layer 340 may also include an antiferromagnetic material for fixing the magnetization direction. For example, the fixed layer 340 may include at least one metal material among Co, Fe, and Ni. In addition, the fixed layer 340 may also include at least one of non-magnetic materials such as boron (B), zinc (Zn), aluminum (Al), titanium (Ti), ruthenium (Ru), tantalum (Ta), silicon (Si), silver (Ag), gold (Au), copper (Cu), carbon (C), and nitrogen (N).

[0087] Although the fixed layer 340 is shown as having a single-layer structure, this is an example and the present disclosure is not limited thereto. In some embodiments, the fixed layer 340 may be provided in a synthetic antiferromagnetic structure (SAF).

[0088] The magnetization direction of the fixed layer 340 is fixed, and according to the stored data, the magnetization direction of the movable element 20 may be parallel or antiparallel to the magnetization direction of the fixed layer 340.

[0089] The fixed layer 340 may overlap with a part (referred to as the magnetic conversion part 222) of the movable element 20 in the vertical direction (e.g., the Z direction). Therefore, in the racetrack memory device 1, the magnetic tunnel junction structure may read data corresponding to the magnetization direction of the magnetic conversion part 222.

[0090] When the movable element 20 and the fixed layer 340 of the magnetic tunnel junction structure are in a parallel state, in other words, the magnetic tunnel junction structure shows a low resistance, and this state may be defined as the data 0 (zero) state. On the contrary, when the movable element 20 and the fixed layer 340 of the magnetic tunnel junction structure are in an antiparallel state, in other words, the magnetic tunnel junction structure shows a high resistance, and this state may be defined as the data 1 (one) state. In some embodiments, the magnetic tunnel junction structure in the antiparallel state may be defined as being in the data 0 state, and the magnetic tunnel junction structure in the parallel state may be defined as being in the data 1 state.

[0091] Figure 4A and 4B is a reference diagram for describing a method of generating magnetic domains according to the current direction in the write element 10 according to an embodiment.

[0092] Reference Figure 4A , a first voltage may be applied between the first electrode E1 and the second electrode E2 such that a first current flows in the write element 10 in the first horizontal direction (I SOT, for example, flow in the +Y direction). Then, in the first spin-orbit torque layer 110, a spin current polarized in a specific direction is generated by the first current, so that a corresponding first spin-orbit torque can be induced. For example, in the first spin-orbit torque layer 110, a spin current polarized in the -X direction is generated, so that a corresponding first spin-orbit torque can be induced. Through the interaction between the magnetic field in the effective horizontal direction (EE, for example, the -Y direction) generated by the magnetic hard mask 150 and the induced spin-orbit torque, the magnetization direction of the first free layer 120 can be rotated, and thus magnetization switching can be performed. Then, the first free layer 120 can generate magnetic domains having a magnetization direction in the -Z direction.

[0093] Reference Figure 4B , a voltage can be applied between the first electrode E1 and the second electrode E2 so that the first current in the write element 10 flows in the second horizontal direction (i.e., the direction opposite to the first horizontal direction (I SOT , for example, the -Y direction)). Then, in the first spin-orbit torque layer 110, a spin current polarized in a direction opposite to the first horizontal direction (EE, for example, the -Y direction) perpendicular to the first horizontal direction (for example, in the +X direction) is generated by the first current, so that a corresponding first spin-orbit torque can be induced. Through the interaction between the magnetic field in the effective horizontal direction (for example, the -Y direction) generated by the magnetic hard mask 150 and the first spin-orbit torque, the magnetization direction of the first free layer 120 can be rotated, and thus magnetization switching can be performed. Then, the first free layer 120 can generate magnetic domains having a magnetization direction in the +Z direction.

[0094] Figures 5A to 5D Shows the measurement results of the size of the magnetic domains according to the pulse width of the second current according to an embodiment. Figure 5A Shows the result of applying a second current with a pulse width of 30 nm to the mobile element 20. Figure 5B Shows the result of applying a second current with a pulse width of 10 nm to the mobile element 20. Figure 5C Shows the result of applying a second current with a pulse width of 3 nm to the mobile element 20. Figure 5D Shows the result of applying a second current with a pulse width of 1 nm to the mobile element 20. Figures 5A to 5D Each of them includes an image on the graph. Included in Figures 5A to 5D Each image is a magneto-optical Kerr effect (MOKE) microscopic image obtained by photographing the racetrack memory device 1, and each graph shows the graph result of the luminance intensity versus the distance to the image. The emission intensity is related to the magnetization direction of the magnetic domains. In Figures 5A to 5DIn the graph, the region where the luminescence intensity has a value greater than the reference value may represent a magnetic domain having a magnetization direction in the +Z direction, and the region where the luminescence intensity has a value less than the reference value may represent a magnetic domain having a magnetization direction in the -Z direction opposite to the +Z direction.

[0095] Referring to Figures 5A to 5D , it can be checked that when a second current with a pulse width of 30 nm is applied to the moving element 20, three magnetic domains (i.e., 3-bit data) are stored in the moving element 20. When a second current with a pulse width of 10 nm is applied to the moving element 20, five magnetic domains, i.e., 5-bit data, are stored in the moving element 20. In addition, it can be checked that when a second current with a pulse width of 3 nm is applied to the moving element 20, seven magnetic domains (i.e., 7-bit data) are stored in the moving element 20. When a second current with a pulse width of 1 nm is applied to the moving element 20, ten magnetic domains, i.e., 10-bit data, are stored in the moving element 20. In other words, it can be checked that as the pulse width of the second current decreases, more magnetic domains can be moved or stored in the moving element 20.

[0096] Figures 6A to 6E is a reference diagram for describing the operation of the racetrack memory device 1 according to an embodiment.

[0097] In Figure 6A , in the writing element 10, a first voltage can be applied between the first electrode E1 and the second electrode E2 to allow a first current to flow in the first horizontal direction (e.g., the +Y direction). Then, in the first spin-orbit torque layer 110, a spin current polarized in the -X direction corresponding to the first current is generated, so that a corresponding first spin-orbit torque can be induced. Through the interaction between the magnetic field in the effective horizontal direction (e.g., the -Y direction) generated by the magnetic hard mask 150 and the first spin-orbit torque, a magnetic domain having a magnetization direction in the -Z direction can be generated in the first free layer 120.

[0098] Referring to Figure 6B, a second current of a pulse type can be applied to the write element 10 and the mobile element 20 through the first to third electrodes E1, E2, and E3. For example, the first electrode E1 and the second electrode E2 can be grounded, and a second voltage of a pulse type can be applied through the third electrode E3. The sign of the second voltage can be negative. A spin current polarized in the first horizontal direction (e.g., +Y direction) is generated by the second current in the second spin-orbit torque layer 210, such that a second spin-orbit torque corresponding to the spin current can be induced. The above spin-orbit torque can include a torque in the vertical direction (e.g., Z direction) in the first free layer 120 and a torque in the second horizontal direction (e.g., +X direction). Although the torque in the vertical direction (e.g., Z direction) does not affect the movement of the magnetic domain, the torque in the second horizontal direction (e.g., +X direction) can move the magnetic domain included in the first free layer 120 in the second horizontal direction (e.g., +X direction), such that the magnetic domain can be injected into the second free layer 220 (i.e., the mobile element 20).

[0099] The intensity of the second voltage (or the absolute value of the second voltage) for moving or storing the magnetic domain can be less than or equal to the intensity of the first voltage (or the absolute value of the first voltage). Since the second voltage moves the magnetic domain in the second horizontal direction, it is not important that the second voltage is less than the first voltage for magnetization switching. For example, the intensity of the second voltage can be 1 / 2 or less of the intensity of the first voltage, or the intensity of the second voltage can be a multiple of the Gilbert damping constant of the intensity of the first voltage or less.

[0100] Referring to Figure 6C , a second current of a pulse type can be continuously applied to the write element 10 and the mobile element 20 through the first to third electrodes E1, E2, and E3. For example, the first electrode E1 and the second electrode E2 can be grounded, and a second voltage of a pulse type can be applied through the third electrode E3. The magnetic domain included in the second spin-orbit torque layer 210 can be moved in the second horizontal direction (e.g., +X direction) by the second current, and the magnetic domain included in the first free layer 120 can be moved in the second horizontal direction (e.g., +X direction) to be injected into the second free layer 220 (i.e., the mobile element 20). Since the movement of the magnetic domain is described above in Figure 6A , a detailed description thereof is omitted.

[0101] As Figure 6DAs shown, in order to allow a first current to flow in the writing element 10 in a direction opposite to the first horizontal direction (e.g., the -Y direction), a first voltage can be applied between the first electrode E1 and the second electrode E2. Then, a spin current polarized in the +X direction is generated by the first current in the first spin-orbit torque layer 110, such that a corresponding first spin-orbit torque can be induced. Through the interaction between the magnetic field in the effective horizontal direction (e.g., the -Y direction) generated by the magnetic hard mask 150 and the first spin-orbit torque, the magnetization direction of the first free layer 120 can be rotated counterclockwise, and thus magnetization switching can be performed. Then, the free layer 120 can generate magnetic domains having a magnetization direction in the +Z direction.

[0102] As Figure 6E shown, a second current of a pulse type can be applied to the writing element 10 and the moving element 20 through the first to third electrodes E1, E2, and E3. Through the second current, the magnetic domains included in the second free layer 220 move in the second horizontal direction (e.g., the +X direction), and the magnetic domains included in the first free layer 120 move in the second horizontal direction (e.g., the +X direction) so as to be injected into the second free layer 220 (i.e., the moving element 20).

[0103] Although the magnetic domains are described above as being moved in the second horizontal direction (e.g., the +X direction) by a second voltage, the present invention is not limited thereto. When the direction of the current is reversed, the moving direction of the magnetic domains can be the opposite direction.

[0104] Figure 7A is a cross-sectional view of a part of a racetrack memory device including a plurality of magnetic hard masks according to another embodiment, and Figure 7B is Figure 7A a plan view of a part of the racetrack memory device.

[0105] Referring to Figure 7A and Figure 7B , the magnetic hard mask 150 can include a first magnetic hard mask 151 and a second magnetic hard mask 152 that are separated from each other. The first magnetic hard mask 151 and the second magnetic hard mask 152 can be separated from each other in the first horizontal direction (e.g., the +Y direction). The first magnetic hard mask 151 and the second magnetic hard mask 152 can be respectively located outside the first electrode E1 and the second electrode E2. The first magnetic hard mask 151 and the second magnetic hard mask 152 are arranged symmetrically with respect to the center axis of the writing element 10, and can generate a magnetic field in the effective horizontal direction (EE, e.g., the +Y direction) in the first free layer 120. Since the moving element 20 and the reading element 30 of Figure 3 are adopted herein, a detailed description thereof is omitted.

[0106] Figure 8Cross-sectional view of a write element 10b according to another embodiment. Figure 9 is a perspective view of a racetrack memory device 1b including Figure 8 write element 10b. Referring to Figure 8 and Figure 9 , write element 10b may include a first ferromagnetic layer 160 that generates a spin current polarized in a vertical direction (e.g., +Z direction), a first spin-orbit torque layer 110 disposed on the first ferromagnetic layer 160, a first free layer 120 disposed on the first spin-orbit torque layer 110, and a first oxide layer 130 disposed on the first free layer 120. The first spin-orbit torque layer 110, the first free layer 120, and the first oxide layer 130 may correspond to Figure 2 the first spin-orbit torque layer 110, the first free layer 120, and the first oxide layer 130 described in

[0107] The first ferromagnetic layer 160 may include a ferromagnetic material having in-plane magnetic anisotropy. The ferromagnetic material may include at least one of Fe, Co, and Ni. The ferromagnetic layer has a magnetization direction aligned in a first horizontal direction (e.g., Y direction).

[0108] The first ferromagnetic layer 160 may be disposed below the first spin-orbit torque layer 110 in contact therewith. When the first ferromagnetic layer 160 is disposed in contact with the first spin-orbit torque layer 110, the thickness of the first ferromagnetic layer 160 does not need to be as large as Figure 2 the magnetic hard mask 150 described in

[0109] The first ferromagnetic layer 160 may have any thickness capable of generating horizontal magnetic anisotropy characteristics. In contrast, the first free layer 120 has perpendicular magnetic anisotropy characteristics, and thus, the thickness of the first free layer 120 may be less than or equal to the thickness of the first ferromagnetic layer 160.When a first current is applied to the first ferromagnetic layer 160, in the first ferromagnetic layer 160, the spin current polarized in the first horizontal direction (e.g., +Y direction or -Y direction) is changed to the vertical direction (e.g., +Z direction or -Z direction) at the interface between the first ferromagnetic layer 160 and the first spin-orbit torque layer 110. When the first current is also applied to the first spin-orbit torque layer 110, in the first spin-orbit torque layer 110, the spin current is polarized in the second horizontal direction (e.g., +X direction or -X direction), so that the corresponding spin-orbit torque can be induced. The magnetization switching can be effectively performed in the first free layer 120 by the spin current polarized in the vertical direction (e.g., +Z direction or -Z direction) and the spin current polarized in the second horizontal direction (e.g., +X direction or -X direction). In other words, even when the magnetization direction in the first free layer 120 maintains symmetry, the spin current polarized in the vertical direction (e.g., +Z direction or -Z direction) can easily control the magnetization direction of the first free layer 120.

[0110] The moving element 20 may include a second ferromagnetic layer 260, a second spin-orbit torque layer 210, a second free layer 220, and a second oxide layer 230. The second ferromagnetic layer 260, the second spin-orbit torque layer 210, the second free layer 220, and the second oxide layer 230 may respectively correspond to the first ferromagnetic layer 160, the first spin-orbit torque layer 110, the first free layer 120, and the first oxide layer 130. The second ferromagnetic layer 260, the second spin-orbit torque layer 210, the second free layer 220, and the second oxide layer 230 may be integrally formed with the first ferromagnetic layer 160, the first spin-orbit torque layer 110, the first free layer 120, and the first oxide layer 130, respectively.

[0111] The intensity of the second voltage applied to the writing element 10 and the moving element 20 may be less than the intensity of the first voltage applied to the writing element 10. For example, the intensity of the second voltage may be 1 / 3 or less, 1 / 5 or less, or 1 / 10 or less of the intensity of the first voltage. Since the intensity of the second voltage is less than the intensity of the first voltage, the spin currents of the first ferromagnetic layer 130 and the second ferromagnetic layer 260 do not affect the injection and movement of magnetic domains. Therefore, the spin current polarized in the first horizontal direction (e.g., +Y direction or -Y direction) generated in the second spin-orbit torque layer 210 can move the magnetic domains. The method for the moving element 20 to move the magnetic domains is described above, so the detailed description thereof is omitted.

[0112] Figure 10 is a cross-sectional view of a writing element 10c according to another embodiment. Figure 11 is including Figure 10 of the writing element 10c of the track memory device 1c. Refer toFigure 10 and Figure 11 , the writing element 10c may include a first antiferromagnetic layer 170, a first free layer 120, and a first oxide layer 130.

[0113] The first antiferromagnetic layer 170 may include a material that breaks the symmetry of the magnetization direction with respect to the first free layer 120 and simultaneously generates a spin current. The first antiferromagnetic layer 170 may include a material in which the magnetization directions in the +Y direction and the -Y direction are alternately aligned in the vertical direction. For example, the first antiferromagnetic layer 170 may be a metal layer such as IrMn or PtMn.

[0114] An exchange bias field corresponding to the magnetization direction of the first antiferromagnetic layer 170 is generated at the interface between the first antiferromagnetic layer 170 and the first free layer 120. In other words, the exchange bias field of the first antiferromagnetic layer 170 provides the same effect as an external magnetic field applied to the first free layer 120, such that the magnetization direction of the first free layer 120 is tilted in the horizontal direction (e.g., the +Y direction or the -Y direction). In this state, when a first current is applied to the first antiferromagnetic layer 170, a magnetization switching is generated in the first free layer 120 by the spin current generated in the first antiferromagnetic layer 170, such that magnetic domains can be generated.

[0115] The moving element 20c may include a second antiferromagnetic layer 270, a second free layer 220, and a second oxide layer 230. The second antiferromagnetic layer 270, the second free layer 220, and the second oxide layer 230 may respectively correspond to the first antiferromagnetic layer 170, the first free layer 120, and the first oxide layer 130. The second antiferromagnetic layer 270, the second free layer 220, and the second oxide layer 230 may be formed integrally with the first antiferromagnetic layer 170, the first free layer 120, and the first oxide layer 130, respectively.

[0116] The intensity of the second voltage applied to the writing element 10c and the moving element 20c may be less than the intensity of the first voltage applied to the writing element 10c. For example, the intensity of the second voltage may be 1 / 2 or less, 1 / 5 or less, or 1 / 10 or less of the intensity of the first voltage. Alternatively, the intensity of the second voltage may be a multiple of the Gilbert damping constant or less of the intensity of the first voltage. Since the intensity of the second voltage is less than the intensity of the first voltage, the exchange bias fields of the first and second antiferromagnetic layers 170 and 270 do not affect the injection and movement of magnetic domains. Therefore, the spin current generated by the second current in the first antiferromagnetic layer 170 and the second antiferromagnetic layer 270 can move the magnetic domains. Since the method of the moving element 20c moving the magnetic domains has been described above, a detailed description thereof is omitted.

[0117] The racetrack memory devices 1, 1b, and 1c according to embodiments can be used in memory devices. Specifically, since selective magnetization switching of the first free layer 120 is possible without applying an external magnetic field, high-speed operation would be possible without having to provide a complex structure for applying an external magnetic field. In the racetrack memory devices 1, 1b, and 1c according to embodiments, since the write elements 10, 10a, 10b, and 10c for generating magnetic domains are separated from the mobile elements 20, 20a, 20b, and 20c for storing magnetic domains, different powers can be used to generate and store magnetic domains, thereby improving power efficiency. Further, since the size of the magnetic domains can be adjusted by the pulse size of the second current, the capacity of the racetrack memory devices 1, 1b, and 1c can be flexibly adjusted.

[0118] Figure 12 is a schematic perspective view of one memory cell including the racetrack memory device 1 according to an embodiment. Refer to Figure 12 , the memory cell MC may include the racetrack memory device 1 and a switching device TR connected to the racetrack memory device 1. The switching device TR may be a thin film transistor. The memory cell MC may be connected between a bit line BL (not shown) and a word line WL. The bit line BL and the word line WL may be arranged to intersect each other, and the memory cell MC may be located at the intersection. The bit line BL may be electrically connected to the fourth electrode E4 of the racetrack memory device 1 (100), and the word line WL may be connected to the gate of the switching device TR. Further, the first source / drain electrode of the switching device TR may be electrically connected to the second electrode E2 of the racetrack memory device 1, and its second source / drain electrode may be electrically connected to the source line SL. In this structure, write current and read current may be applied to the memory cell MC through the word line WL and the bit line BL. The racetrack memory devices 1, 1b, and 1c according to some embodiments may also be applied to the memory cell MC.

[0119] Figure 13 is schematically showing including Figure 12 of a memory device 400 configured with a plurality of memory cells. Refer to Figure 13 , the memory device 400 may include a plurality of bit lines BL, a plurality of word lines WL, a plurality of source lines SL, a plurality of memory cells MC (each memory cell MC being located at each intersection between the bit line BL and the word line WL), a bit line driver 401 for applying current to the bit line BL, a word line driver 402 for applying current to the word line WL, and a source line driver 403 for applying current to the source line SL. Each memory cell MC may have the Figure 12 configuration illustrated in. Figure 13 The memory device 400 illustrated in may be, for example, a magnetic random access memory (MRAM), and may be used in an electronic device using non-volatile memory.

[0120] The memory device 400 described above can be used to store data in various electronic devices. Figure 14 is a conceptual diagram schematically showing a device architecture applicable to an electronic device 500 according to an embodiment. Referring to Figure 14 , the electronic device 500 may include a main memory 510, an auxiliary storage device 520, a central processing unit (CPU) 530, and input / output devices 540 (e.g., a keyboard, a display). The CPU 530 may include a cache memory 531, an arithmetic logic unit (ALU) 532, and a control unit 533. The cache memory 531 may include static random access memory (SRAM). According to an embodiment, the main memory 510 may include a DRAM device, and the auxiliary storage device 520 may include the memory device 400. Alternatively, according to an embodiment, the cache memory 531, the main memory 510, and the auxiliary storage device 520 may all include the memory device 400. In some cases, the electronic device 500 may be implemented such that the computing unit device and the memory unit device are adjacent to each other in one chip without distinguishing the above-mentioned sub-units.

[0121] It should be understood that the above-mentioned racetrack memory device and the electronic device including the racetrack memory device described herein should be considered only in a descriptive sense and not for the purpose of limitation. The description of features or aspects within each embodiment should generally be considered applicable to other similar features or aspects in other embodiments.

[0122] One or more of the elements disclosed above may include a processing circuit or be implemented in a processing circuit, such as hardware including logic circuits; a hardware / software combination, such as a processor executing software; or a combination thereof. For example, the processing circuit may more specifically include, but is not limited to, a central processing unit (CPU), an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate array (FPGA), a system on a chip (SoC), a programmable logic unit, a microprocessor, an application specific integrated circuit (ASIC), etc.

[0123] Although one or more embodiments have been described with reference to the accompanying drawings, those of ordinary skill in the art will understand that various changes in form and detail may be made therein without departing from the spirit and scope defined by the appended claims.

Claims

1. A racetrack memory device, comprising: A write element extending in a first horizontal direction and configured to generate magnetic domains based on a first current applied to the write element; A moving element having a first end connected to the write element, the moving element extending in a second horizontal direction that intersects the first horizontal direction, the moving element being configured to inject the magnetic domains generated in the write element into the moving element based on a second current applied to the moving element; And A read element on the moving element and configured to read the magnetic domains included in the moving element, Wherein the width of the moving element is less than the width of the write element.

2. The track memory device according to claim 1, wherein, The ratio of the width of the write element to the width of the moving element is 1.5 or greater.

3. The track memory device according to claim 2, wherein, The ratio of the width of the write element to the width of the moving element is 5 or less.

4. The track memory device according to claim 1, wherein, The ratio of the length of the write element to the width of the moving element is 2 or greater.

5. The track memory device according to claim 1, wherein The write element is configured to generate magnetic domains having a magnetization direction corresponding to the direction of the first current.

6. The racetrack memory device according to claim 1, wherein, The write element is configured to generate the magnetic domains such that if the direction of the first current applied to the write element is parallel to the first horizontal direction, then the magnetic domains have a first magnetization direction, and The write element is configured to generate the magnetic domains such that if the direction of the first current applied to the write element is opposite to the first horizontal direction, then the magnetic domains have a second magnetization direction, and The second magnetization direction is opposite to the first magnetization direction.

7. The racetrack memory device according to claim 6, wherein, If a first magnetic domain having the first magnetization direction is already in the write element, then the write element is configured to: if the direction of the first current applied to the write element is opposite to the first horizontal direction, then change the magnetic domain in the write element from the first magnetic domain to a second magnetic domain having the second magnetization direction.

8. The track memory device according to claim 1, wherein, The size of the magnetic domains injected into the moving element is based on the pulse width of the second current.

9. The track memory device according to claim 8, wherein, The size of the magnetic domains injected into the moving element is proportional to the pulse width of the second current.

10. The track memory device according to claim 1, wherein, The intensity of the second current is less than or equal to the intensity of the first current.

11. The track memory device according to claim 10, wherein, The intensity of the second current is 1 / 2 or less of the intensity of the first current.

12. The track memory device according to claim 1, wherein, The pulse width of the first current and the pulse width of the second current are equal.

13. The racetrack memory device according to claim 1, further comprising: A first electrode at a first end of the write element; A second electrode at a second end of the write element, the second end of the write element being opposite to the first end of the write element; And A third electrode connected to a second end of the moving element, the second end of the moving element being different from the first end of the moving element.

14. The racetrack memory device according to claim 1, wherein, The racetrack memory device is configured to apply the first current through the first electrode and the second electrode, and the racetrack memory device is configured to apply the second current through the third electrode while the first electrode and the second electrode are grounded.

15. The racetrack memory device according to claim 1, wherein, the write element includes: a first spin-orbit torque layer configured to induce a first spin-orbit torque based on the first current, a first free layer on the first spin-orbit torque layer and configured to generate the magnetic domain based on the first spin-orbit torque, a first oxide layer on the first free layer, an insulating layer on the first oxide layer, and a magnetic hard mask configured to form a magnetic field in an effective horizontal direction in the first free layer, and the mobile element includes: a second spin-orbit torque layer configured to induce a second spin-orbit torque through the second current, the second spin-orbit torque layer corresponding to the first spin-orbit torque layer, a second free layer on the second spin-orbit torque layer, and the mobile element is configured to inject the magnetic domain into the second free layer based on the second spin-orbit torque, and a second oxide layer on the second free layer.

16. The track memory device according to claim 15, wherein, The magnetic hard mask is on the insulating layer.

17. The racetrack memory device according to claim 15, wherein, the magnetic hard mask overlaps the first free layer in a vertical direction and does not overlap the second free layer, and the vertical direction intersects the first horizontal direction and the second horizontal direction.

18. The racetrack memory device according to claim 15, wherein, the magnetic hard mask includes a first magnetic hard mask and a second magnetic hard mask separated from each other in the first horizontal direction.

19. The racetrack memory device according to claim 1, wherein, the write element includes: a first ferromagnetic layer having horizontal magnetic anisotropy, a first spin-orbit torque layer on the first ferromagnetic layer and configured to induce a first spin-orbit torque based on the first current, and a first free layer on the first spin-orbit torque layer and configured to generate the magnetic domain based on the first spin-orbit torque, and the mobile element includes: a second ferromagnetic layer in the same plane as the first ferromagnetic layer, a second spin-orbit torque layer on the second ferromagnetic layer and configured to induce a second spin-orbit torque, and a second free layer on the second spin-orbit torque layer and configured to inject the magnetic domain into the second free layer based on the second spin-orbit torque.

20. The racetrack memory device according to claim 1, wherein, the write element includes: a first antiferromagnetic layer configured to generate a first spin current using an exchange bias field based on the first current, and a first free layer on the first antiferromagnetic layer and configured to generate the magnetic domain using the exchange bias field based on the first spin current, and the mobile element includes: A second antiferromagnetic layer, on the same plane as the first antiferromagnetic layer and configured to generate a second spin current based on the second current, and A second free layer, on the second antiferromagnetic layer, the mobile element being configured to inject the magnetic domain into the second free layer based on the second spin current.

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