Polymorphic magnetic storage unit, preparation method and application thereof

Abstract

The invention discloses a polymorphic magnetic storage unit, a preparation method and application thereof, the polymorphic magnetic storage unit comprises three magnetic arms and nodes at the joints of the three magnetic arms, the three magnetic arms form an integrated T-shaped structure, and the three magnetic arms are made of magnetized materials; the magnetic arm is used for adjusting the magnetization state of the magnetic arm according to an external magnetic head; the node is used for adjusting the magnetization state of the node according to the magnetization state of the magnetic arm; the magnetization states of the nodes include eight different node magnetization states. The state of the magnetic storage unit can be increased, the form limitation of stored data is reduced, and the method can be widely applied to the field of microelectronic storage devices.

Description

Technical Field

[0001] The present invention relates to the field of microelectronic storage devices, and in particular to a polymorphic magnetic storage unit, a preparation method and application thereof. Background Art

[0002] In recent years, with the continuous improvement of integrated circuit manufacturing technology, the size of devices has gradually decreased, but due to the limitation of quantum effects, problems such as low reliability and high power consumption have emerged in the industry, making it difficult to maintain "Moore's Law" in the microelectronics industry. In order to solve the performance problem of integrated circuits, many scholars have begun to look for breakthroughs at all levels from materials to systems. As an emerging discipline, spin electronics uses electron spin for signal generation, transmission and processing, involving multiple fields such as magnetism, electronics and informatics, and has the advantages of non-volatility, low power consumption and high integration.

[0003] Magnetic storage units are products that use electron spin to generate, transmit and process signals. However, existing magnetic storage units have fewer resistance states and have greater limitations on the form of stored data. Summary of the invention

[0004] In order to solve the above problems, the purpose of the present invention is to provide a multi-state magnetic storage unit, a preparation method and application thereof, which can increase the states of the magnetic storage unit and reduce the form restrictions of stored data.

[0005] On the one hand, the present invention provides a polymorphic magnetic storage unit, comprising three magnetic arms and nodes at the connection points of the three magnetic arms, wherein the three magnetic arms and the nodes form an integrated T-shaped structure, and the materials of the three magnetic arms are all magnetized materials;

[0006] The magnetic arm is used to adjust the magnetization state of the magnetic arm according to the external magnetic head, and the node is used to adjust the magnetization state of the node according to the magnetization state of the magnetic arm; the magnetization state of the node includes at least eight different node magnetization states.

[0007] Optionally, if the external magnetic head generates a first external magnetic field on a horizontal plane, the magnetization state of the magnetic arm is a first magnetic arm magnetization state, and the magnetization state of the node is a first node magnetization state;

[0008] If the external magnetic head generates a second external magnetic field on a horizontal plane, the magnetization state of the magnetic arm is a second magnetic arm magnetization state, and the magnetization state of the node is a second node magnetization state;

[0009] If the external magnetic head generates a third external magnetic field on a horizontal plane, the magnetization state of the magnetic arm is a third magnetic arm magnetization state, and the magnetization state of the node is a third node magnetization state;

[0010] If the external magnetic head generates a fourth external magnetic field on a horizontal plane, the magnetization state of the magnetic arm is a fourth magnetic arm magnetization state, and the magnetization state of the node is a fourth node magnetization state.

[0011] Optionally, if the external magnetic head generates a first external magnetic field on a horizontal plane and a fifth external magnetic field on a vertical plane, the magnetization state of the magnetic arm is a fifth magnetic arm magnetization state, and the magnetization state of the node is a fifth node magnetization state;

[0012] If the external magnetic head generates a second external magnetic field on the horizontal plane and a sixth external magnetic field on the vertical plane, the magnetization state of the magnetic arm is the sixth magnetic arm magnetization state, and the magnetization state of the node is the sixth node magnetization state;

[0013] If the external magnetic head generates a third external magnetic field on the horizontal plane and a seventh external magnetic field on the vertical plane, the magnetization state of the magnetic arm is the seventh magnetic arm magnetization state, and the magnetization state of the node is the seventh node magnetization state;

[0014] If the external magnetic head generates a fourth external magnetic field on the horizontal plane and an eighth external magnetic field on the vertical plane, the magnetization state of the magnetic arm is the eighth magnetic arm magnetization state, and the magnetization state of the node is the eighth node magnetization state.

[0015] Optionally, the magnetized material includes a soft magnetic amorphous alloy.

[0016] Optionally, the T-shaped structure is a thin film, and the film is wrapped with at least one metal protective layer.

[0017] Optionally, the thickness of the metal protection layer is in the range of 1-6 nanometers, and the thickness of the film is in the range of 20-35 nanometers.

[0018] Optionally, the width of the node is in the range of 90-110 nanometers.

[0019] Optionally, the lengths of the three magnetic arms are all in the range of 600-700 nanometers.

[0020] On the other hand, the present invention provides an application of a magnetic storage unit, where the magnetic storage unit described above is applied to a multi-base storage device, and each magnetization state of a node corresponds to a base number.

[0021] In another aspect, the present invention provides a method for preparing a magnetic storage unit, which is used to prepare the magnetic storage unit described above, comprising the following steps:

[0022] A thin film is prepared on a substrate using a magnetized material;

[0023] Etching a T-shaped structure on the film; the T-shaped structure includes three magnetic arms and nodes where the three magnetic arms are connected;

[0024] At least one metal protection layer is deposited on the surface of the T-shaped structure to obtain a magnetic storage unit.

[0025] The implementation of the present invention includes the following beneficial effects: the magnetic storage unit of the present invention includes three magnetic arms and nodes at the connections of the three magnetic arms, the three magnetic arms form an integrated T-shaped structure, the materials of the three magnetic arms are all magnetized materials, the magnetic arms are used to adjust the magnetization state of the magnetic arms according to the external magnetic head, the nodes are used to adjust the magnetization state of the nodes according to the magnetization state of the magnetic arms, the magnetization state of the nodes includes at least eight different node magnetization states, and through the three integrated T-shaped magnetic arms, the nodes at the intersection of the magnetic arms can generate at least eight different node magnetization states under the action of the external magnetic field, thereby increasing the magnetization state of the magnetic storage unit and reducing the restrictions on the form of stored data. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of a polymorphic magnetic storage unit provided by the present invention;

[0027] Figure 2 It is a schematic diagram of four node magnetization states provided by the present invention;

[0028] Figure 3 It is a schematic diagram of storing two octal numbers in a magnetic storage unit provided by the present invention;

[0029] Figure 4 It is another schematic diagram of storing two octal numbers in a magnetic storage unit provided by the present invention;

[0030] Figure 5 It is a flow chart of the steps of preparing a magnetic storage unit provided by the present invention.

[0031] A-node; B-magnetic arm; C-magnetic arm; D-magnetic arm; Hx-external magnetic field applied by the external magnetic head to the magnetic arm in the horizontal positive direction; Hy-external magnetic field applied by the external magnetic head to the magnetic arm in the vertical positive direction; -Hx-external magnetic field applied by the external magnetic head to the magnetic arm in the horizontal negative direction; -Hy-external magnetic field applied by the external magnetic head to the magnetic arm in the vertical negative direction; the internal arrow represents the magnetization direction inside the magnetic arm or the node. DETAILED DESCRIPTION

[0032] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The step numbers in the following embodiments are only provided for the convenience of explanation and description, and the order between the steps is not limited in any way. The execution order of each step in the embodiment can be adaptively adjusted according to the understanding of those skilled in the art.

[0033] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the embodiments of the present application. The singular forms of "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0034] When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the attached claims. In the description of the present application, it should be understood that the terms "first", "second", "third", etc. are only used to distinguish similar objects, and do not have to be used to describe a specific order or sequence, nor can they be understood as indicating or implying relative importance. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0035] In an embodiment, -Hz- the external magnetic field applied by the external magnetic head to the magnetic arm in the vertical negative direction.

[0036] like Figure 1 As shown, Figure 1 The present invention provides a multi-state magnetic storage unit, comprising three magnetic arms and nodes at the connection points of the three magnetic arms, wherein the three magnetic arms and the nodes form an integrated T-shaped structure, and the materials of the three magnetic arms are all magnetized materials;

[0037] The magnetic arm is used to adjust the magnetization state of the magnetic arm according to the external magnetic head, and the node is used to adjust the magnetization state of the node according to the magnetization state of the magnetic arm; the magnetization state of the node includes at least eight different node magnetization states.

[0038] In some embodiments, Figure 2 As shown, Figure 2 It is a schematic diagram of four node magnetization states. In the figure, numbers 0-3 represent four node magnetization states (four magnetization directions) of four nodes respectively. Each node magnetization state can be used as an octal number storage state.

[0039] If the external magnetic head generates a first external magnetic field on a horizontal plane, the magnetization state of the magnetic arm is a first magnetic arm magnetization state, and the magnetization state of the node is a first node magnetization state.

[0040] Specifically, Figure 2As shown, the first external magnetic field is (Hx, Hy), the magnetization state of the magnetic arm is the first magnetic arm magnetization state, the node is the first node magnetization state 0, characterized by the magnetization direction pointing to the upper right, and the angle between the magnetization direction and the positive direction of the x-axis on the horizontal plane is 40°-50°, specifically, 45°.

[0041] If the external magnetic head generates a second external magnetic field on the horizontal plane, the magnetization state of the magnetic arm is the second magnetic arm magnetization state, and the magnetization state of the node is the second node magnetization state.

[0042] Specifically, Figure 2 As shown, the second external magnetic field is (-Hx, Hy), the magnetization state of the magnetic arm is the second magnetic arm magnetization state, and the node is the second node magnetization state 1, characterized by the magnetization direction pointing to the upper left, and the angle between the magnetization direction and the positive direction of the x-axis on the horizontal plane is 130°-140°, specifically, 135°.

[0043] If the external magnetic head generates a third external magnetic field on the horizontal plane, the magnetization state of the magnetic arm is the third magnetic arm magnetization state, and the magnetization state of the node is the third node magnetization state.

[0044] Specifically, Figure 2 As shown, the third external magnetic field is (-Hx, -Hy), the magnetization state of the magnetic arm is the third magnetic arm magnetization state, and the node is the third node magnetization state 2, characterized by the magnetization direction pointing to the lower left, and the angle between the magnetization direction and the positive direction of the x-axis on the horizontal plane is 220°-230°, specifically, 225°.

[0045] If the external magnetic head generates a fourth external magnetic field on the horizontal plane, the magnetization state of the magnetic arm is a fourth magnetic arm magnetization state, and the magnetization state of the node is a fourth node magnetization state.

[0046] Specifically, Figure 2 As shown, the fourth external magnetic field is (Hx, -Hy), the magnetization state of the magnetic arm is the fourth magnetic arm magnetization state, and the node is the fourth node magnetization state 3, characterized by the magnetization direction pointing to the lower right, and the angle between the magnetization direction and the positive direction of the x-axis on the horizontal plane is 310°-320°, specifically, 315°.

[0047] In some embodiments, if the external magnetic head generates a first external magnetic field on a horizontal plane and a fifth external magnetic field on a vertical plane, the magnetization state of the magnetic arm is a fifth magnetic arm magnetization state, and the magnetization state of the node is a fifth node magnetization state.

[0048] Specifically, a first external magnetic field is generated on the horizontal plane and a fifth external magnetic field is generated on the vertical plane as (Hx, Hy, -Hz), the magnetization state of the magnetic arm is the fifth magnetic arm magnetization state, and the node is the fifth node magnetization state 4, characterized in that the magnetization direction points to the upper right on the horizontal plane and deviates from the horizontal plane by a certain angle, the angle between the magnetization direction and the positive direction of the x-axis on the horizontal plane is 40°-50°, specifically 45°, and on the vertical plane, the angle between the magnetization direction and the horizontal plane is 40°-50°, specifically 45°.

[0049] If the external magnetic head generates a second external magnetic field on the horizontal plane and a sixth external magnetic field on the vertical plane, the magnetization state of the magnetic arm is the sixth magnetic arm magnetization state, and the magnetization state of the node is the sixth node magnetization state.

[0050] Specifically, the external magnetic head generates a second external magnetic field on the horizontal plane and a sixth external magnetic field on the vertical plane as (-Hx, Hy, -Hz), the magnetization state of the magnetic arm is the sixth magnetic arm magnetization state, and the node is the sixth node magnetization state 5, characterized by the magnetization direction pointing to the upper left on the horizontal plane and deviating from the horizontal plane by a certain angle, the angle between the magnetization direction and the positive direction of the x-axis on the horizontal plane is 130°-140°, specifically 135°, and on the vertical plane, the angle between the magnetization direction and the horizontal plane is 40°-50°, specifically 45°.

[0051] If the external magnetic head generates a third external magnetic field on the horizontal plane and a seventh external magnetic field on the vertical plane, the magnetization state of the magnetic arm is the seventh magnetic arm magnetization state, and the magnetization state of the node is the seventh node magnetization state.

[0052] Specifically, the external magnetic head generates a third external magnetic field on the horizontal plane and a seventh external magnetic field on the vertical plane as (-Hx, -Hy, -Hz), the magnetization state of the magnetic arm is the seventh magnetic arm magnetization state, and the node is the seventh node magnetization state 6, characterized by the magnetization direction pointing to the lower left on the horizontal plane and deviating from the horizontal plane by a certain angle, the angle between the magnetization direction and the positive direction of the x-axis on the horizontal plane is 220°-230°, specifically 225°, and on the vertical plane, the angle between the magnetization direction and the horizontal plane is 40°-50°, specifically 45°.

[0053] If the external magnetic head generates a fourth external magnetic field on the horizontal plane and an eighth external magnetic field on the vertical plane, the magnetization state of the magnetic arm is the eighth magnetic arm magnetization state, and the magnetization state of the node is the eighth node magnetization state.

[0054] Specifically, the external magnetic head generates a fourth external magnetic field on the horizontal plane and an eighth external magnetic field on the vertical plane as (Hx, -Hy, -Hz), the magnetization state of the magnetic arm is the eighth magnetic arm magnetization state, and the node is the eighth node magnetization state 7, characterized by the magnetization direction pointing to the lower right on the horizontal plane and deviating from the horizontal plane by a certain angle, the angle between the magnetization direction and the positive direction of the x-axis on the horizontal plane is 310°-320°, specifically 315°, and on the vertical plane, the angle between the magnetization direction and the horizontal plane is 40°-50°, specifically 45°.

[0055] In the above embodiment, a case is provided in which the fifth magnetic field and the eighth magnetic field are the same and are -Hz. In some embodiments, the fifth magnetic field and the eighth magnetic field may also be different, thereby generating other node magnetization states.

[0056] In some embodiments, the magnetized material includes a soft magnetic amorphous alloy, such as CoFeB in a thin film.

[0057] In some embodiments, the T-shaped structure is a thin film, and the outside of the thin film is further wrapped with at least one metal protective layer. For example, the metal protective layer can be but is not limited to an aluminum (Al) protective layer.

[0058] In some embodiments, the thickness of the metal protective layer ranges from 1 to 6 nanometers, and the thickness of the film ranges from 20 to 35 nanometers. For example, the thickness of the metal protective layer can be 5 nanometers, and the thickness of the film can be 30 nanometers. It is easy to understand that since the three magnetic arms and the node are integrated, the thickness of the three magnetic arms and the node is the same, which is the sum of the thickness of the film and the thickness of the protective layer.

[0059] In some embodiments, the width of the node is in the range of 90-110 nanometers, for example, the width of the node may be 100 nanometers.

[0060] In some embodiments, the lengths of the three magnetic arms are all in the range of 600-700 nanometers. For example, the lengths of the three magnetic arms may be 650 nanometers.

[0061] In some embodiments, Figure 3-4 As shown, Figure 3 It is a schematic diagram of the storage of two octal numbers in a magnetic storage unit. Figure 4 This is another schematic diagram of storing two octal numbers in a magnetic storage unit. The present invention provides an application of a magnetic storage unit, which applies the above-mentioned magnetic storage unit to a multi-base storage device, wherein each node magnetization state of the node corresponds to a base number.

[0062] The multi-base system may be, but is not limited to, binary and octal.

[0063] Taking the application of the magnetic storage unit as an octal memory as an example, when data is written into the octal memory device, the external magnetic head adds an external magnetic field to the magnetic arm, the magnetization state of the magnetic arm changes to the magnetic arm magnetization state corresponding to the external magnetic field, and the magnetization state of the node changes to the node magnetization state corresponding to the magnetic arm magnetization state.

[0064] When reading data from the octal storage device, the node magnetization state of the node is detected to obtain an octal number corresponding to the node magnetization state.

[0065] For example, by applying an electric pulse, the magnetic head as an electromagnetic element generates a corresponding magnetic field, thereby changing the magnetization state of the magnetic storage unit. Each node magnetization state of the node corresponds to an octal number, such as Figure 3 , one of the node's magnetic directions is parallel to the plane formed by the x-axis and the y-axis. On this plane, the angle between the node's magnetic direction and the x-axis is about 220°-230°, corresponding to the octal number 2, or binary 10. One of the node's magnetic directions is parallel to the plane formed by the x-axis and the y-axis. On this plane, the angle between the node's magnetic direction and the x-axis is within 310°-320°, corresponding to the octal number 3, or binary 11. On this plane, the angle between the node's magnetic direction and the x-axis is about 40°-50°, corresponding to the octal number 0, or 00. On this plane, the angle between the node's magnetic direction and the x-axis is about 130°-140°, corresponding to the octal number 1, or binary 01.

[0066] Specifically, the eight node magnetization states of the node can correspond to the octal numbers "0", "1", "2", "3", "4", "5", "6", and "7", respectively. The correspondence between each node magnetization state of the node and the octal number is not limited here. It is easy to understand that simply changing the correspondence between the node magnetization state and the octal number should also be within the scope of protection of this patent.

[0067] During the process of writing and reading data, the external magnetic head does not directly contact the magnetic storage unit but is suspended on the surface of the magnetic arm of the T-shaped structure.

[0068] Of course, the magnetic storage unit of the present invention can also be used as a binary or other base storage device. When used as a binary storage device, two magnetization states of the magnetic storage unit can be used, and one magnetic storage unit can store two binary numbers at the same time.

[0069] In the above manner, the storage capacity of the magnetic storage unit can be saved. For example, an octal number 2 (corresponding to binary 10) can be stored using only one magnetic storage unit. However, if a magnetic storage unit with only two states is used, one magnetic storage unit is required to store 1 and another magnetic storage unit is required to store 0.

[0070] like Figure 5 As shown, Figure 5 The present invention provides a method for preparing a magnetic storage unit, which is used to prepare the magnetic storage unit according to any one of claims 1 to 9, comprising the following steps:

[0071] S100, preparing a thin film on a substrate using a magnetized material.

[0072] The material of the substrate may be, but is not limited to, single crystal silicon or a non-ferromagnetic alloy material. The magnetized material is the same as explained above.

[0073] Specifically, a thin film is grown on the substrate by using vacuum sputtering technology, and the film and thickness are the same as explained above.

[0074] S200, etching a T-shaped structure on the film.

[0075] The T-shaped structure includes three magnetic arms and nodes where the three magnetic arms are connected.

[0076] Specifically, an ion beam etching technique is used to etch a T-shaped structure on the film, and the lengths and widths of the three magnetic arms and the nodes where the three magnetic arms are connected are the same as explained above.

[0077] S300 , depositing a protective layer on the surface of the T-shaped structure to obtain a magnetic storage unit.

[0078] Specifically, a protective layer is deposited on the surface of the T-shaped structure to obtain a magnetic storage unit, and the meaning of the protective layer is the same as the above explanation.

[0079] The implementation of the present invention includes the following beneficial effects: the present invention uses three integrated T-shaped magnetic arms to enable the nodes at the intersection of the magnetic arms to generate eight different node magnetization states under the action of an external magnetic field, thereby increasing the magnetization state of the magnetic storage unit and reducing restrictions on the form of stored data.

[0080] When the present invention is applied to a magnetic storage unit, eight different node magnetization states can be made to correspond to octal numbers, thereby saving the storage capacity of the storage device.

[0081] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0082] The above is a specific description of the preferred implementation of the present invention, but the invention is not limited to the embodiments. Those skilled in the art may make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A multi-state magnetic storage unit, characterized in that: It includes three magnetic arms and three nodes at the connection points of the magnetic arms, the three magnetic arms and the nodes form an integrated T-shaped structure, and the materials of the three magnetic arms are all magnetized materials; The magnetic arm is used to adjust the magnetization state of the magnetic arm according to the external magnetic head, and the node is used to adjust the magnetization state of the node according to the magnetization state of the magnetic arm; the magnetization state of the node includes at least eight different node magnetization states.

2. The magnetic storage unit according to claim 1, characterized in that If the external magnetic head generates a first external magnetic field on a horizontal plane, the magnetization state of the magnetic arm is a first magnetic arm magnetization state, and the magnetization state of the node is a first node magnetization state; If the external magnetic head generates a second external magnetic field on a horizontal plane, the magnetization state of the magnetic arm is a second magnetic arm magnetization state, and the magnetization state of the node is a second node magnetization state; If the external magnetic head generates a third external magnetic field on a horizontal plane, the magnetization state of the magnetic arm is a third magnetic arm magnetization state, and the magnetization state of the node is a third node magnetization state; If the external magnetic head generates a fourth external magnetic field on a horizontal plane, the magnetization state of the magnetic arm is a fourth magnetic arm magnetization state, and the magnetization state of the node is a fourth node magnetization state.

3. The magnetic storage unit according to claim 1, characterized in that If the external magnetic head generates a first external magnetic field on a horizontal plane and a fifth external magnetic field on a vertical plane, the magnetization state of the magnetic arm is a fifth magnetic arm magnetization state, and the magnetization state of the node is a fifth node magnetization state; If the external magnetic head generates a second external magnetic field on the horizontal plane and a sixth external magnetic field on the vertical plane, the magnetization state of the magnetic arm is the sixth magnetic arm magnetization state, and the magnetization state of the node is the sixth node magnetization state; If the external magnetic head generates a third external magnetic field on the horizontal plane and a seventh external magnetic field on the vertical plane, the magnetization state of the magnetic arm is the seventh magnetic arm magnetization state, and the magnetization state of the node is the seventh node magnetization state; If the external magnetic head generates a fourth external magnetic field on the horizontal plane and an eighth external magnetic field on the vertical plane, the magnetization state of the magnetic arm is the eighth magnetic arm magnetization state, and the magnetization state of the node is the eighth node magnetization state.

4. The magnetic storage unit according to claim 1, characterized in that The magnetized material includes a soft magnetic amorphous alloy.

5. The magnetic storage unit according to claim 4, characterized in that The T-shaped structure is a thin film, and the outside of the thin film is also wrapped with at least one metal protective layer.

6. The magnetic storage unit according to claim 5, characterized in that The thickness of the metal protection layer is in the range of 1-6 nanometers, and the thickness of the film is in the range of 20-35 nanometers.

7. The magnetic storage unit according to claim 6, characterized in that The width of the nodes ranges from 90-110 nanometers.

8. The magnetic storage unit according to claim 6, characterized in that The lengths of the three magnetic arms are all in the range of 600-700 nanometers.

9. An application of a magnetic storage unit, characterized in that: The magnetic storage unit according to any one of claims 1 to 8 is applied to a multi-base storage device, and each magnetization state of a node corresponds to a base number.

10. A method for preparing a magnetic storage unit, characterized in that: The method for preparing the magnetic storage unit according to any one of claims 1 to 8 comprises the following steps: A thin film is prepared on a substrate using a magnetized material; Etching a T-shaped structure on the film; the T-shaped structure includes three magnetic arms and nodes where the three magnetic arms are connected; At least one metal protection layer is deposited on the surface of the T-shaped structure to obtain a magnetic storage unit.

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