Magnetic recording system, magnetic sequence writing method and data storage system
Through antiferromagnetic/ferromagnetic double-layer magnetic continuous film structure and energy-assisted writing technology, the problem of limited improvement space for existing tape storage units and bit storage is solved, and multi-bit storage and efficient storage capacity are improved.
Patent Information
- Application Number
- CN202510233068.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-28
- Publication Date
- 2025-07-04
AI Technical Summary
Existing two-dimensional storage technologies such as hard disks and optical disks are facing storage stability and capacity saturation problems. In tape technology, storage unit size and bit storage improvement space are limited, and the flexible substrate limits the capacity expansion potential of three-dimensional storage.
The antiferromagnetic/ferromagnetic double-layer magnetic continuous film is used as the storage unit, and multi-bit storage is realized using the energy-assisted writing method. The magnetic field larger than the ferromagnetic layer coercive field and the heating auxiliary head are applied by the write head to flip the magnetic moments of the ferromagnetic layer and the antiferromagnetic layer.
It realizes the formation of multiple consecutive states in a single memory cell, significantly improving storage capacity, and reducing the complexity of the write head through simplified writing technology, improving storage stability and capacity.
Smart Images
Figure CN120260622A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of data storage, and in particular to a magnetic recording system, a magnetic order writing method, and a data storage system. Background Art
[0002] With the rise of emerging information technologies such as big data and artificial intelligence, the total amount of data has increased exponentially over time. Most of this data is cold data, that is, data with a low frequency of access times. The storage capacities of common technologies in the market such as mechanical hard disks, solid-state drives, and optical discs have gradually reached their limits, and the costs are relatively high. The storage of a large amount of cold data has become one of the core factors hindering the further development of information technology.
[0003] Current hard disk and optical disc technologies store information on the surface of a rigid substrate, which belongs to two-dimensional (2D) storage. As the storage unit volume continues to shrink, the storage stability and reading reliability are gradually facing challenges, and the miniaturization process is difficult to continue, and the storage capacity tends to saturate. Even if the current method of stacking multiple disk surfaces is used, the capacity can be further increased, but limited by the overall chassis volume, the number of disk surfaces is small. For example, IBM or Seagate uses 8 stacked disk surfaces to increase the capacity. In comparison, tape technology grows the magnetic medium for storing information on a flexible substrate, and multiple storage tracks are arranged in parallel on the tape surface. For example, currently LTO9 arranges nearly 9000 tracks on a tape surface with a width of about 1 centimeter order of magnitude, and then rolls up the tape surface. Since the thickness of the flexible substrate adjacent to the tape surface is extremely low, currently LTO9 is about 5 micrometers, forming a three-dimensional (3D) memory with extremely high density per unit volume. Compared with 2D storage technologies such as hard disks and optical discs, tape uses the advantage of the flexible substrate that can be curled, and utilizes the longitudinal tape surface width dimension in information storage, having extremely high expansion potential.
[0004] However, limited by the flexible substrate's restrictions on aspects such as the growth and processing temperature of magnetic materials, as of now, the area of the storage unit of one of the highest tape technologies, LTO9, is about 50 nanometers * 1000 nanometers, which consists of many independent nano-magnetic particles. Common magnetic materials include BaFe, SrFe, etc. The size of the magnetic particles is about dozens of nanometers, and the storage unit is binary bit storage, having a high room for improvement in terms of storage unit size and storage bits. Summary of the Invention
[0005] To solve at least one of the problems proposed in the above background art section, the present application provides a magnetic recording system, a magnetic order writing method, and a data storage system, and proposes to use an antiferromagnetic / ferromagnetic bilayer magnetic continuous film as a storage unit, which can achieve multi-bit storage, and uses an energy-assisted writing method to complete the writing of multi-bit information of the storage unit.
[0006] In a first aspect, an embodiment of the present invention provides a magnetic recording system, including a magnetic order writing device and a magnetic recording structure, where:
[0007] The magnetic recording structure includes a substrate and a stacked structure disposed on the substrate, where: the substrate is used to provide mechanical support for the stacked structure; the stacked structure sequentially includes a seed layer and a storage track layer, where:
[0008] The storage track layer includes a plurality of continuous storage tracks, each of the storage tracks includes a plurality of continuous storage units, and each of the storage units includes an antiferromagnetic layer and a ferromagnetic layer disposed above the antiferromagnetic layer, where: the seed layer is used to deposit the antiferromagnetic layer; the antiferromagnetic layer is used to provide an exchange bias field for the ferromagnetic layer, and the exchange bias field is configured to be greater than the coercive field of the ferromagnetic layer, and the structures of the ferromagnetic layer and the antiferromagnetic layer are thin film structures or granular structures, where the storage unit can achieve multi-bit storage;
[0009] The magnetic order writing device is disposed above the ferromagnetic layer and includes a write head and a heat-assisted head, where:
[0010] The write head is used to apply a magnetic field to a to-be-written area in the ferromagnetic layer, and the heat-assisted head is used to heat the to-be-written areas in the ferromagnetic layer and the antiferromagnetic layer when the write head applies the magnetic field, so that the magnetic moments of the to-be-written areas in the ferromagnetic layer and the antiferromagnetic layer are flipped, where the to-be-written area is close to the heat-assisted head, and the magnetic field is greater than the coercive field of the ferromagnetic layer.
[0011] In some alternative ways of this embodiment, after the to-be-written area in the antiferromagnetic layer is heated by the heat-assisted head, the exchange bias field in the to-be-written area of the antiferromagnetic layer disappears.
[0012] In some alternative ways of this embodiment, the exchange bias field in the antiferromagnetic layer far from the heat-assisted head remains unchanged, and the magnetic moments of the non-written areas in the ferromagnetic layer and the antiferromagnetic layer far from the heat-assisted head remain unchanged.
[0013] In some alternative ways of this embodiment, the to-be-written area of the ferromagnetic layer and the to-be-written area of the antiferromagnetic layer form a first magnetic domain, the non-written area of the ferromagnetic layer and the non-written area of the antiferromagnetic layer form a second magnetic domain, and the magnetic recording system further includes a write controller, where:
[0014] The first magnetic domain and the second magnetic domain satisfy perpendicular anisotropy or in-plane anisotropy;
[0015] The writing controller is used to control the writing area of the write head on the ferromagnetic layer to adjust the ratio of the perpendicular anisotropy or the ratio of the in-plane anisotropy, so as to realize multi-bit storage of the storage unit.
[0016] In some alternative embodiments of this embodiment, it further includes:
[0017] An insulating layer disposed between the substrate and the seed layer, which is used to block the heat transfer from the heating assist head to the substrate.
[0018] In some alternative embodiments of this embodiment, it further includes:
[0019] A back coating disposed on one side of the substrate away from the seed layer, which is used to reduce the static electricity of the substrate.
[0020] In some alternative embodiments of this embodiment, when the material of the antiferromagnetic layer is one or any combination of platinum manganese, iridium manganese, palladium manganese, and iron manganese, the thickness of the antiferromagnetic layer is between 1 nm and 50 nm;
[0021] When the material of the antiferromagnetic layer is one or any combination of nickel oxide, chromium sesquioxide, iridium manganese oxide, and bismuth ferrite, the thickness of the antiferromagnetic layer is between 1 nm and 100 nm.
[0022] In a second aspect, the present invention further provides a magnetic order writing method for a magnetic recording system based on the foregoing first aspect, including:
[0023] The write head applies a magnetic field to the area to be written of the ferromagnetic layer, wherein the magnetic field is greater than the coercive field of the ferromagnetic layer;
[0024] When the write head applies a magnetic field to the ferromagnetic layer, the heating assist head heats the areas to be written of the ferromagnetic layer and the antiferromagnetic layer;
[0025] The write head and the heating assist head act together to flip the magnetic moments of the areas to be written in the ferromagnetic layer and the antiferromagnetic layer, so as to realize magnetic order writing of the ferromagnetic layer and the antiferromagnetic layer in the area to be written.
[0026] In some alternative embodiments of this embodiment, the area to be written of the ferromagnetic layer and the area to be written of the antiferromagnetic layer form a first magnetic domain, the non-written area of the ferromagnetic layer and the non-written area of the antiferromagnetic layer form a second magnetic domain, the first magnetic domain and the second magnetic domain satisfy perpendicular anisotropy or in-plane anisotropy, the magnetic recording system further includes a writing controller, and the magnetic order writing method further includes:
[0027] The writing controller determines the ratio of the perpendicular anisotropy or the ratio of the in-plane anisotropy based on the storage requirements of the storage unit;
[0028] The writing controller determines the area to be written based on the ratio of the perpendicular anisotropy or the ratio of the in-plane anisotropy, so as to achieve multi-bit storage of the storage unit.
[0029] In a third aspect, the present invention further provides a data storage system, including the magnetic recording system of the foregoing first aspect.
[0030] A magnetic recording system, a magnetic order writing method, and a data storage system provided by embodiments of the present invention propose to use an antiferromagnetic / ferromagnetic double-layer magnetic continuous film as a storage unit, which can achieve multi-bit storage, and use the energy-assisted writing method to complete the writing of multi-bit information of the storage unit; each storage track is a continuous film layer based on the above structure, and each specific length in each track is used as a storage unit. Each storage unit can form a magnetic domain structure, and the ratio of the magnetic domains in the ferromagnetic layer pointing up and down determines the amplitude of the tape read signal. Through this structural design, a continuous plurality of states can be formed in a single storage unit, that is, multi-bit storage can be achieved, thereby greatly improving the storage capacity. In addition, the invention also includes the writing technology of the tape. By applying a magnetic field greater than the coercive field of the ferromagnetic layer to the area to be written through a write head, the writing of the ferromagnetic layer is completed, and at the same time, with the assistance of a heating head on the scale of dozens of nanometers, the writing of the antiferromagnetic magnetic order is completed, and finally the change of the magnetic domain direction near the heating head is achieved. BRIEF DESCRIPTION OF THE DRAWINGS
[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings. In the drawings:
[0032] Figure 1 is a schematic structural diagram of the magnetic recording system in an embodiment of the present invention;
[0033] Figure 2 is a top view of the magnetic recording structure in an embodiment of the present invention;
[0034] Figure 3 is a second top view of the magnetic recording structure in an embodiment of the present invention;
[0035] Figure 4 is a first writing principle of the multi-domain state storage unit in an embodiment of the present invention;
[0036] Figure 5 is a second writing principle of the multi-domain state storage unit in an embodiment of the present invention;
[0037] Figure 6 Schematic flowchart of the magnetic order writing method in an embodiment of the present invention;
[0038] Figure 7 Schematic structural diagram of a data storage system in an embodiment of the present invention. Detailed implementation manners
[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer and more understandable, the following further describes the embodiments of the present invention in detail with reference to the accompanying drawings. Herein, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but not to limit the present invention.
[0040] It should be noted that in the embodiments of the present application, some existing solutions in the industry such as certain software, components, models, etc. may be mentioned. They should be regarded as exemplary, and their purpose is only to illustrate the feasibility in the implementation of the technical solutions of the present application, but it does not mean that the applicant has already or necessarily used this solution.
[0041] In the prior art, ferromagnetic materials themselves have the characteristic of low storage stability at the nanoscale, and there is only binary storage, resulting in limited storage capacity of magnetic tapes. In view of this, the present application proposes a magnetic recording system, as Figure 1 shown. The magnetic recording system includes a magnetic order writing device 10 and a magnetic recording structure 20, where:
[0042] The magnetic recording structure 20 includes a substrate 200 and a stacked structure disposed on the substrate. Among them: the substrate 200 is used to provide mechanical support for the stacked structure; the stacked structure sequentially includes a seed layer 202 and a storage track layer, where:
[0043] As Figure 2 shown, the storage track layer includes a plurality of continuous storage tracks (such as storage track 1, storage track 2, storage track 3... storage track n), as Figure 3 shown. Each of the storage tracks includes a plurality of continuous storage units, as Figure 4 or Figure 5 shown. Each of the storage units includes an antiferromagnetic layer (i.e., the antiferromagnetic layer 203 in Figure 1 ) and a ferromagnetic layer disposed above the antiferromagnetic layer (i.e., the ferromagnetic layer 204 in Figure 1 ). Among them: as Figure 1 shown, the seed layer 202 is used to deposit the antiferromagnetic layer 203; the antiferromagnetic layer 203 is used to provide an exchange bias field for the ferromagnetic layer 204, and the exchange bias field is configured to be greater than the coercive field of the ferromagnetic layer 204. The structures of the ferromagnetic layer 204 and the antiferromagnetic layer 203 are thin film structures or particle structures. Among them, the storage unit can achieve multi-bit storage;
[0044] The magnetic order writing device 10 is disposed above the ferromagnetic layer 204 and includes a write head (i.e., the Figure 1 magnetic field write head in) and a heat-assisted head, where:
[0045] The write head is used to apply a magnetic field to the area to be written in the ferromagnetic layer, and the heat-assisted head is used to heat the area to be written in the ferromagnetic layer and the area to be written in the antiferromagnetic layer when the write head applies the magnetic field, so that the magnetic moments of the area to be written in the ferromagnetic layer and the area to be written in the antiferromagnetic layer are both flipped. Among them, the area to be written is close to the heat-assisted head, and the magnetic field is greater than the coercive field of the ferromagnetic layer.
[0046] Specifically, the ferromagnetic layer refers to a material with a strong spin-coupling effect, and the spin directions tend to be parallelly arranged, having a relatively high saturation magnetization intensity. The antiferromagnetic layer refers to a material in which adjacent spins are arranged in opposite directions, so there is no net magnetic moment, and it is often used to provide a stable magnetic environment.
[0047] The exchange bias field is a bias effect generated due to the interaction between adjacent ferromagnetic and antiferromagnetic materials in some spin systems. It is often used in magnetic materials and devices, especially in applications such as storage devices and magnetic sensors. The exchange bias field comes from the exchange interaction between the ferromagnetic layer and the antiferromagnetic layer. When these two materials are in close contact, the spins in the ferromagnetic layer will be affected by the antiferromagnetic material at the contact interface, causing an offset in the spin arrangement, thereby forming a constant bias field.
[0048] The exchange bias field needs to be greater than the coercivity of the ferromagnetic layer, which ensures that the ferromagnetic layer has enough force to overcome the influence of the external magnetic field. The coercivity is the critical value of the reverse magnetic field that needs to be applied to make the magnetization of the material completely zero after the external magnetic field is removed.
[0049] In some optional ways of this embodiment, after the area to be written in the antiferromagnetic layer is heated by the heat-assisted head, the exchange bias field of the area to be written in the antiferromagnetic layer disappears.
[0050] Specifically, after heating, the spin arrangement of the antiferromagnetic layer may be affected, resulting in a weakening or disappearance of the exchange interaction between it and the ferromagnetic layer. At this time, the magnetization of the ferromagnetic layer can rotate under a smaller external magnetic field, facilitating the writing of new data. After the writing is completed, the cooling process will restore the original properties of the antiferromagnetic layer, thereby re-establishing the exchange bias.
[0051] In some alternative embodiments of the present embodiment, the exchange bias field in the antiferromagnetic layer away from the heating assist head remains unchanged, and the magnetic moments of the non-writing area in the ferromagnetic layer away from the heating assist head and the non-writing area in the antiferromagnetic layer away from the heating assist head remain unchanged.
[0052] In some alternative embodiments of the present embodiment, the area to be written in the ferromagnetic layer and the area to be written in the antiferromagnetic layer form a first magnetic domain, and the non-writing area in the ferromagnetic layer and the non-writing area in the antiferromagnetic layer form a second magnetic domain. Figure 4 and Figure 5 Shows the area 401 to be written in the ferromagnetic layer, the area 301 to be written in the antiferromagnetic layer, the non-writing area in the ferromagnetic layer, and the non-writing area in the antiferromagnetic layer. Among them, the non-writing area in the ferromagnetic layer is the area on the ferromagnetic layer outside the area 401 to be written; the non-writing area in the antiferromagnetic layer is the area on the antiferromagnetic layer outside the area 301 to be written.
[0053] It should be noted that the ferromagnetic layer and the antiferromagnetic layer can also be referred to as information storage layers. Further, the magnetic recording system further includes a write controller, where:
[0054] The first magnetic domain and the second magnetic domain satisfy perpendicular anisotropy or in-plane anisotropy;
[0055] The write controller is used to adjust the ratio of the perpendicular anisotropy or the ratio of the in-plane anisotropy by controlling the writing area (i.e., the area of the area to be written) of the write head in the ferromagnetic layer, so as to achieve multi-bit storage of the storage unit. In some alternative embodiments of the present embodiment, as Figure 1 shown, the stacked structure further includes:
[0056] An insulating layer 201 disposed between the substrate 200 and the seed layer 202, which is used to block the heat transfer from the heating assist head to the substrate.
[0057] Specifically, the insulating layer refers to an insulating material or structure used in tape storage devices, especially in tapes for data and audio storage (such as audio tapes, video tapes, and data backup tapes). These insulating layers are also used to protect the magnetic materials and stored content in the tape, ensuring the stability and reliability of the tape during use and storage.
[0058] In some alternative embodiments of the present embodiment, as Figure 1 shown, the magnetic recording system further includes:
[0059] A back coating 30 disposed on the side of the substrate 200 away from the seed layer 202, which is used to reduce the static electricity of the substrate.
[0060] Specifically, the back coating refers to a specific coating material applied to the back of the magnetic tape, which is usually used to enhance the performance and durability of the magnetic tape. The main functions of this coating are to protect the magnetic material of the magnetic tape, improve the performance of the magnetic tape, and enhance its operating characteristics. Common coating materials include polymer coatings and coating additives. Among them, polymer coatings: Polymer materials such as polyester (PET) are commonly used for the back coating of magnetic tapes, which have good chemical stability and mechanical strength; Coating additives: Specific chemical additives may be added to the coating to enhance wear resistance, water resistance, and oxidation resistance.
[0061] In some alternative embodiments of the present embodiment, when the material of the antiferromagnetic layer is one or any combination of platinum manganese, iridium manganese, palladium manganese, and iron manganese, the thickness of the antiferromagnetic layer is between 1 nm and 50 nm;
[0062] When the material of the antiferromagnetic layer is one or any combination of nickel oxide, chromium sesquioxide, iridium manganese oxide, and bismuth ferrite, the thickness of the antiferromagnetic layer is between 1 nm and 100 nm.
[0063] A magnetic recording system provided by an embodiment of the present invention proposes to use a bilayer magnetic continuous film of antiferromagnetic / ferromagnetic as a storage unit, which can achieve multi-bit storage, and complete the writing of multi-bit information of the storage unit by means of energy-assisted writing; Each storage track is a continuous film layer based on the above structure, and each specific length in each track is used as a storage unit. Each storage unit can form a magnetic domain structure. The ratio of the magnetic domains of the ferromagnetic layer pointing up and down determines the amplitude of the read signal of the magnetic tape. Through this structural design, multiple continuous states can be formed in a single storage unit, that is, multi-bit storage can be achieved, thereby greatly improving the storage capacity. The invention also includes the writing technology of the magnetic tape. By applying a magnetic field greater than the coercive field of the ferromagnetic layer to the area to be written by the write head, the writing of the ferromagnetic layer is completed. At the same time, with the assistance of a heating head on the scale of dozens of nanometers, the writing of the antiferromagnetic magnetic order is completed, and finally the change of the magnetic domain direction near the heating head is realized.
[0064] Next, the above embodiments will be described with specific structures:
[0065] The storage medium of the magnetic tape in the present invention is different from traditional independent nano-magnetic particles, but is composed of a continuous film layer based on the antiferromagnetic / ferromagnetic bilayer film structure. Each storage track is a continuous film layer based on the above structure, and each specific length in each track is used as a storage unit. Each storage unit can form a magnetic domain structure. As Figure 4 shown, the magnetic domains of the ferromagnetic layer point up and down (as Figure 5As shown, for the in-plane magnetic anisotropy system, the ratio of left and right determines the amplitude of the tape read signal. Through this structural design, multiple continuous states can be formed in a single storage unit, which can realize multi-bit storage, thereby greatly improving the storage capacity. The present application also includes the writing technology of the tape, which completes the writing of the ferromagnetic layer by applying a magnetic field greater than the coercive field of the ferromagnetic layer to the area to be written by the write head, and completes the writing of the antiferromagnetic magnetic order with the assistance of a heating head of tens of nanometers, and finally realizes the change of the direction of the magnetic domain near the heating head.
[0066] In terms of storage media, Figure 1 As shown in the figure, the complete magnetic tape film structure includes a ferromagnetic layer, an antiferromagnetic layer, a seed layer, a thermal insulation layer, a substrate and a back coating. The specific film structure and mechanism of action are as follows:
[0067] The ferromagnetic layer is a well-known ferromagnetic material, whose magnetization direction is vertical or in-plane, can be flipped by a vertical or in-plane magnetic field, and the coercive field is smaller than the exchange bias field. For example, metals selected from Cr, Mn, Co, Fe and Ni and alloys containing one or more of these metals and exhibiting ferromagnetism can be used, and alloys containing these metals and at least one element of B, C and N are also included, specifically, for example, Co-Fe, Co-Fe-B, Ni-Fe, CoNi, CoPt, BaFe and SrFe.
[0068] The antiferromagnetic layer provides an exchange bias field for the ferromagnetic layer, and the exchange bias field is greater than the coercive field of the ferromagnetic layer. The antiferromagnetic layer material includes but is not limited to one or any combination of platinum manganese (PtMn), iridium manganese (IrMn), palladium manganese (PdMn) and iron manganese (FeMn), and the thickness can be 1nm-50nm. The common element ratio of PtMn can be Pt 50 Mn 50 , Pt 20 Mn 80 , Pt 25 Mn 75 or Pt 75 Mn 25 Materials such as IrMn; the commonly used element ratio of Ir 50 Mn 50 , Ir 20 Mn 80 or Ir 25 Mn 75 Materials such as PdMn; the commonly used element ratio of Pd 50 Mn 50 , Pd 90 Mn 10 or Pd 75 Mn 25 Materials such as FeMn; the commonly used element ratio of Fe50 Mn 50 or Fe 80 Mn 20 and other materials. The numbers in the above materials represent the percentage of elements. In addition, it can also be one or any combination of nickel oxide (NiO), chromium sesquioxide (Cr2O3), yttrium manganite (YMnO3), and bismuth ferrite (BiFeO3), and the thickness can be 1 - 100 nm. The antiferromagnetic layer should have high thermal stability and resistance to external magnetic fields, have a relatively consistent magnetic moment orientation, and be able to provide a large exchange bias field for the adjacent ferromagnetic layer.
[0069] The seed layer is to make the growth of the antiferromagnetic layer material more orderly and flat, so as to form a sufficiently large exchange bias field. The seed layer material is selected from but not limited to one or more of Nb, Ta, Cr, Mo, W, Re, Ru, Os, Rh, Ir, Pt, Cu, Ag, Au, NiFe, TaB, and TaN, and the thickness range can be 1 - 500 nm.
[0070] The function of the thermal insulation layer is to block the heat transferred by the heat head during the writing process and prevent the magnetic tape substrate from failing due to overheating. The material is selected from but not limited to nano - ceramic films (such as titanium oxide and indium tin oxide, etc.), polyimide films, and polytetrafluoroethylene films, etc., and the thickness range is 0.1 - 5 μm.
[0071] In this application, the substrate provides mechanical support for the magnetic layer, keeps the properties of the magnetic layer unchanged during deformation and bending, and has good recovery ability after multiple bending deformations. The material is selected from but not limited to materials such as polyethylene terephthalate, polyimide, polyvinyl chloride, and polypropylene, and the thickness range is 0.5 - 50 μm.
[0072] The back coating is usually made of materials such as carbon black, ceramic particles, and resin, which can prevent electrostatic accumulation, enhance mechanical durability, and improve the winding characteristics of the magnetic tape.
[0073] Such as Figure 2 shown, multiple storage tracks are arranged on the substrate, and each storage track is a complete antiferromagnetic / ferromagnetic bilayer thin film; as Figure 3 shown, on each storage track, a certain length of the thin film can be used as a storage unit; for each storage unit, different data storage states can be represented by the ferromagnetic / antiferromagnetic magnetic domain directions. Since the area of the magnetic domains with different magnetic moment directions (i.e., the proportion of the shaded part) can be changed by writing, multi - state storage can be formed in a single storage unit, as Figure 4 or Figure 5 shown.
[0074] In terms of writing, the write head includes two main parts. One is the magnetic field generation region that generates a perpendicular magnetic field within a certain range. The magnetic field of the write head can easily flip the ferromagnetic layer over a large range, which includes both the area near the thermal head (i.e., the heating-assisted head) and possibly the area far from the thermal head. The antiferromagnetic layer itself has extremely high magnetic field resistance. Therefore, although the ferromagnetic layer in the area far from the thermal head will be flipped by the write head magnetic field, when the write head magnetic field stops, the ferromagnetic magnetic moment will reset under the action of the exchange bias field. In the area near the thermal head, the antiferromagnetic layer shows an overall disordered state when heated, and the exchange bias field disappears. The magnetic moment of the ferromagnetic layer is flipped under the action of the magnetic field. When the write head stops writing (i.e., the magnetic field stops and the heating stops), the antiferromagnetic layer will be induced to form an exchange bias field in the opposite direction to the initial state, thus stabilizing the ferromagnetic magnetic moment that has been flipped in this area, as Figure 4 and Figure 5 shown. In short, the existence of the exchange bias field enables the continuous ferromagnetic thin film to flip near the thermal head, forming a stable magnetic domain structure.
[0075] So far, the continuous magnetic thin film with an antiferromagnetic / ferromagnetic structure as the storage medium has high storage stability (the antiferromagnetic can improve the storage stability of the ferromagnetic through the exchange bias field), and can present continuously adjustable multi-domain states in storage units of the same size, thus realizing multi-bit storage and greatly improving the storage capacity. By using the heating-assisted magnetic field to flip the antiferromagnetic / ferromagnetic structure, the position of the magnetic domain can be accurately changed, thus realizing the accurate writing of multi-bit storage. At the same time, since the writing of the exchange bias field (antiferromagnetic) depends on heating assistance, this writing method has low requirements for the write head magnetic field focusing, and can effectively reduce the complexity of the write head. The growth and processing of the continuous thin film are relatively convenient, and can reduce the process complexity of the tape storage medium processing.
[0076] It should be noted that in this application, the antiferromagnetic / ferromagnetic bilayer film structure is used as the tape storage medium to improve storage stability and increase storage capacity. Different from the magnetic particles in the prior art, the continuous magnetic thin film in this application can realize multi-bit storage and increase storage capacity through the generation and regulation of multi-domain states. The writing of the antiferromagnetic / ferromagnetic storage medium relies on the magnetic field generated by the write head and the heating assistance of the thermal head. The special writing mechanism proposed based on the material characteristics ensures the reliability and stability of multi-bit writing.
[0077] The embodiment of this application also provides a magnetic order writing method for a magnetic recording system based on the foregoing embodiment, as Figure 6 shown. This method includes:
[0078] Step S10: The write head applies a magnetic field to the area to be written of the ferromagnetic layer, where the magnetic field is greater than the coercive field of the ferromagnetic layer;
[0079] Step S20: When the write head applies a magnetic field to the ferromagnetic layer, the heating assist head heats the to-be-written regions of the ferromagnetic layer and the antiferromagnetic layer.
[0080] Step S30: The write head and the heating assist head act together to flip the magnetic moments of the to-be-written regions in the ferromagnetic layer and the antiferromagnetic layer, so as to achieve magnetic order writing of the ferromagnetic layer and the antiferromagnetic layer in the to-be-written regions.
[0081] In some alternative embodiments of this embodiment, the to-be-written region of the ferromagnetic layer and the to-be-written region of the antiferromagnetic layer form a first magnetic domain, the non-written region of the ferromagnetic layer and the non-written region of the antiferromagnetic layer form a second magnetic domain, the first magnetic domain and the second magnetic domain satisfy perpendicular anisotropy or in-plane anisotropy, the magnetic recording system further includes a write controller, and the magnetic order writing method further includes:
[0082] The write controller determines the ratio of the perpendicular anisotropy or the ratio of the in-plane anisotropy based on the storage requirements of the storage unit.
[0083] The write controller determines the to-be-written regions based on the ratio of the perpendicular anisotropy or the ratio of the in-plane anisotropy, so as to achieve multi-bit storage of the storage unit.
[0084] It should be noted that the principle of a magnetic order writing method provided in this embodiment is similar to that of the magnetic recording system provided in the foregoing embodiment. The related parts can be referred to the above description and will not be elaborated here.
[0085] An embodiment of the present application further provides a data storage system, as Figure 7 shown. This data storage system includes the magnetic recording system of the foregoing embodiment.
[0086] It should be noted that the principle of a data storage system provided in this embodiment is similar to that of the magnetic recording system provided in the foregoing embodiment. The related parts can be referred to the above description and will not be elaborated here.
[0087] It should be noted that a data storage system is a hardware device or component used to store and access data, which can support different types of data and application requirements, and there are applicable storage solutions from computers to large data centers.
[0088] The specific embodiments described above further elaborate the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
Claims
1. A magnetic recording system, characterized in that, Comprising a magnetic order writing device and a magnetic recording structure, wherein: The magnetic recording structure includes a substrate and a stacked structure disposed on the substrate, wherein: the substrate is used to provide mechanical support for the stacked structure; the stacked structure sequentially includes a seed layer and a storage track layer, wherein: The storage track layer includes a plurality of continuous storage tracks, each of the storage tracks includes a plurality of continuous storage units, each of the storage units includes an antiferromagnetic layer and a ferromagnetic layer disposed above the antiferromagnetic layer, wherein: the seed layer is used to deposit the antiferromagnetic layer; the antiferromagnetic layer is used to provide an exchange bias field for the ferromagnetic layer, and the exchange bias field is configured to be greater than the coercive field of the ferromagnetic layer, and the structures of the ferromagnetic layer and the antiferromagnetic layer are thin film structures or granular structures, wherein, the storage unit can achieve multi-bit storage; The magnetic order writing device is disposed above the ferromagnetic layer and includes a write head and a heat-assisted head, wherein: The write head is used to apply a magnetic field to a write region in the ferromagnetic layer, and the heat-assisted head is used to heat the write regions in the ferromagnetic layer and the antiferromagnetic layer when the write head applies the magnetic field, so that the magnetic moments of the write regions in the ferromagnetic layer and the antiferromagnetic layer are flipped, wherein, the write region is close to the heat-assisted head, and the magnetic field is greater than the coercive field of the ferromagnetic layer.
2. The magnetic recording system according to claim 1, wherein, After the write region in the antiferromagnetic layer is heated by the heat-assisted head, the exchange bias field of the write region in the antiferromagnetic layer disappears.
3. The magnetic recording system according to claim 1, wherein The exchange bias field of the antiferromagnetic layer far from the heat-assisted head remains unchanged, and the magnetic moments of the non-write regions in the ferromagnetic layer and the antiferromagnetic layer far from the heat-assisted head remain unchanged.
4. The magnetic recording system according to claim 3, wherein, The write region of the ferromagnetic layer and the write region of the antiferromagnetic layer form a first magnetic domain, the non-write region of the ferromagnetic layer and the non-write region of the antiferromagnetic layer form a second magnetic domain, and the magnetic recording system further includes a write controller, wherein: The first magnetic domain and the second magnetic domain satisfy perpendicular anisotropy or in-plane anisotropy; The write controller is used to control the write area of the write head in the ferromagnetic layer to adjust the proportion of the perpendicular anisotropy or the proportion of the in-plane anisotropy, so as to achieve multi-bit storage of the storage unit.
5. The magnetic recording system according to claim 1, wherein Further comprising: A heat insulation layer disposed between the substrate and the seed layer, which is used to block the heat transfer from the heat-assisted head to the substrate.
6. The magnetic recording system according to claim 1, wherein, Further comprising: A back coating disposed on the side of the substrate away from the seed layer, which is used to reduce the static electricity of the substrate.
7. The magnetic recording system according to claim 1, wherein When the material of the antiferromagnetic layer is one or any combination of platinum manganese, iridium manganese, palladium manganese, and iron manganese, the thickness of the antiferromagnetic layer is between 1 nm and 50 nm; When the material of the antiferromagnetic layer is one or any combination of nickel oxide, chromium sesquioxide, iridium manganese oxide, and bismuth ferrite, the thickness of the antiferromagnetic layer is between 1 nm and 100 nm.
8. A method for writing a magnetic order in a magnetic recording system according to any one of claims 1-7, characterized in that, Comprising: The write head applies a magnetic field to the write region of the ferromagnetic layer, wherein, the magnetic field is greater than the coercive field of the ferromagnetic layer; When a magnetic field is applied to the ferromagnetic layer by the write head, the heating assist head heats the ferromagnetic layer and the write region of the antiferromagnetic layer; The write head and the heating assist head act together to reverse the magnetic moments of the write regions in the ferromagnetic layer and the antiferromagnetic layer, so as to achieve magnetic order writing of the ferromagnetic layer and the antiferromagnetic layer in the write region.
9. The magnetic order writing method according to claim 8, wherein The write region of the ferromagnetic layer and the write region of the antiferromagnetic layer form a first magnetic domain, the non-write region of the ferromagnetic layer and the non-write region of the antiferromagnetic layer form a second magnetic domain, the first magnetic domain and the second magnetic domain satisfy perpendicular anisotropy or in-plane anisotropy, the magnetic recording system further includes a write controller, and the magnetic order writing method further includes: The write controller determines the ratio of the perpendicular anisotropy or the ratio of the in-plane anisotropy based on the storage requirements of the storage unit; The write controller determines the write region based on the ratio of the perpendicular anisotropy or the ratio of the in-plane anisotropy to achieve multi-bit storage of the storage unit.
10. A data storage system, characterized in that, A magnetic recording system according to any one of claims 1-7 is included.