A FeCoCr magnetic code disk material, its preparation method and application

Abstract

This invention relates to the field of magnetic materials technology. It provides a FeCoCr magnetic code disk material, its preparation method, and its applications. By introducing a MgO layer onto the surface of a FeCoCr thin film and controlling the migration of oxygen elements in the MgO layer at the FeCoCr thin film interface, the coercivity and remanence of the FeCo thin film can be effectively regulated, resulting in significant grain refinement and the formation of a higher α phase at the FeCo interface. After introducing the MgO layer onto the FeCoCr thin film surface, the coercivity of the FeCoCr magnetic code disk material increases from 348 Oe to 397–439 ​​Oe, the remanence increases from 3507 Oe to 6534–8721 Oe, and the remanence ratio increases from 0.71 to 0.76–0.77. This improves the coercivity of the magnetic code disk material and achieves very high remanence, meeting the practical application requirements of magnetic encoder code disks.

Description

Technical Field

[0001] This invention relates to the field of magnetic materials technology, and in particular to a FeCoCr magnetic code disk material, its preparation method, and its application. Background Technology

[0002] The magnetic code disk is a crucial component of a magnetic encoder, and its performance determines the encoder's accuracy. Currently, internationally, magnetic code disk materials have gradually shifted from traditional ferrite materials and magnetic alloys to magnetic alloy thin film materials with higher recording density. FeCrCo alloy thin films possess excellent comprehensive properties and can be considered a potential material for magnetic code disks in magnetic encoders. Therefore, obtaining high-performance FeCrCo thin film materials is crucial for the development of high-precision magnetic encoders. Since the magnetism of a material directly affects the magnetic energy product, materials with high remanence and remanence ratios generate strong magnetic pole signals after magnetization. Increased remanence makes it easier for sensors to detect magnetic elements, significantly improving sensitivity and thus enhancing the accuracy of magnetic rotational encoding. The remanence and remanence ratio of magnetic materials are important performance indicators, and improving the remanence and remanence ratio of magnetic thin films used in magnetic code disks has always been a key research area in magnetic thin films.

[0003] As the core component of a magnetic encoder, the magnetic code disk provides the magnetic signal through tiny written magnetic poles. Since the resolution of a magnetic encoder is highly dependent on the uniformity and magnetic properties of the code disk material, the thin film material used in the code disk needs to possess a certain level of coercivity to ensure the written magnetic pole signal has strong resistance to external disturbances. However, traditional FeCoCr alloy thin films, typically single-layer films, generally have very low coercivity, failing to meet the practical application requirements of magnetic code disks. Furthermore, the remanence and remanence ratio of currently used FeCoCr alloy thin films are not high enough.

[0004] Given the current problems of low coercivity, low remanence and remanence ratio in conventional FeCoCr alloy thin films, it is necessary to improve them. Summary of the Invention

[0005] This invention provides a FeCoCr magnetic code disk material, its preparation method, and its application, in order to overcome the deficiencies in the prior art.

[0006] In a first aspect, the present invention provides a FeCoCr magnetic code disk material, comprising:

[0007] Base;

[0008] A FeCoCr thin film layer is located on the surface of the substrate;

[0009] An MgO layer is located on the surface of the FeCoCr thin film layer and is away from the substrate;

[0010] The thickness of the MgO layer is 2–10 nm.

[0011] Preferably, the FeCoCr magnetic code disk material comprises the following elements by mass fraction: Fe 40-41.5%, Cr 29-30.5%, Co 24-25.5%, Mo 0-4%, and Zr 0-2%.

[0012] Preferably, the FeCoCr magnetic code disk material comprises the following elements by mass fraction: Fe 41%, Cr 30%, Co 25%, Mo 3%, and Zr 1%.

[0013] Preferably, in the FeCoCr magnetic code disk material, the thickness of the MgO layer is 2-5 nm.

[0014] Preferably, the FeCoCr magnetic code disk material has a FeCoCr thin film layer thickness of 50–200 nm.

[0015] Preferably, the FeCoCr magnetic code disk material has a substrate comprising any one of a glass substrate, a silicon substrate, or a polymer substrate.

[0016] Secondly, the present invention also provides a method for preparing the FeCoCr magnetic code disk material, comprising the following steps:

[0017] FeCoCr thin film and MgO layer were sequentially deposited on the substrate, and then annealed to obtain FeCoCr magnetic code disk material.

[0018] Preferably, the method for preparing the FeCoCr magnetic code disk material involves depositing a FeCoCr thin film layer using magnetron sputtering with FeCoCr as the target material; wherein the process parameters controlled by magnetron sputtering are: sputtering power 40-50W, and vacuum degree of the sputtering chamber 1×10⁻⁶. -5 ~3×10 -5 Pa, working gas is argon, argon pressure is 0.3~0.6Pa;

[0019] MgO layers were deposited using magnetron sputtering with MgO as the target material. The process parameters controlled by magnetron sputtering were: sputtering power 80–120 W, and vacuum degree of the sputtering chamber 1 × 10⁻⁶. -5 ~3×10 -5 Pa, working gas is argon, argon pressure is 0.3~0.6Pa.

[0020] Preferably, in the method for preparing the FeCoCr magnetic code disk material, the annealing step involves an annealing temperature of 600–700°C, an annealing time of 0.5–1 h, and an annealing vacuum degree of 1 × 10⁻⁶.-5 ~6×10 -5 Pa.

[0021] Thirdly, the present invention also provides an application of the FeCoCr magnetic code disk material or the FeCoCr magnetic code disk material prepared by the preparation method described above in the preparation of magnetic encoders.

[0022] The present invention has the following advantages over the prior art:

[0023] 1. The FeCoCr magnetic code disk material of the present invention comprises a substrate, a FeCoCr thin film layer, and a MgO layer stacked sequentially; the thickness of the MgO layer is 2-10 nm; the present invention, through the ingenious structural design of introducing an active metal MgO layer on the surface of the FeCoCr thin film layer, and by controlling the migration of oxygen elements in the MgO layer at the FeCoCr thin film layer interface, can effectively regulate the coercivity and remanence of the FeCo thin film layer, significantly refine the grains, and form a higher α phase at the FeCo interface; the present invention, in the FeCoCr thin film... After introducing an MgO layer onto the film surface, compared to the material without an MgO layer, the coercivity of the FeCoCr magnetic code disk material increases from 348 Oe to 397–439 ​​Oe, the remanence increases from 3507 Oe to 6534–8721 Oe, and the remanence ratio increases from 0.71 to 0.76–0.77. In the FeCoCr magnetic code disk material of this invention, after introducing an MgO layer, the remanence increases by as much as 86–148%, the coercivity increases by 14.08–26.15%, and the remanence ratio increases by 7.04–8.45%, meeting practical application requirements.

[0024] 2. The preparation method of the FeCoCr magnetic code disk material of the present invention obtains an MgO layer by depositing a FeCoCr thin film layer. After introducing the MgO layer, the coercivity of the magnetic code disk material is improved and a high remanence is obtained. The magnetic code disk material meets the practical application requirements of magnetic encoder disks. The preparation method of the FeCoCr magnetic code disk material of the present invention is simple, easy to control, efficient and low in cost. It can increase the coercivity and remanence of the thin film material, providing a scientific basis for the practical application of thin film magnetic code disks. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the structure of the FeCoCr magnetic code disk material of the present invention;

[0027] Figure 2 The in-plane hysteresis loop of the FeCoCr magnetic code disk material prepared in Example 1 of this invention;

[0028] Figure 3 The in-plane hysteresis loop of the FeCoCr magnetic code disk material prepared in Example 2 of this invention;

[0029] Figure 4 The in-plane hysteresis loop of the FeCoCr magnetic code disk material prepared in Example 3 of this invention;

[0030] Figure 5 The in-plane hysteresis loop of the FeCoCr magnetic code disk material prepared in Comparative Example 1;

[0031] Figure 6 The XRD patterns of the FeCoCr magnetic code disk materials prepared in Examples 1-3 and Comparative Examples 1-2 of this invention are shown below.

[0032] Figure 7 The graphs show the average grain size of the α-FeCrCo phase in the FeCoCr thin film layers of Examples 1-3 and Comparative Examples 1-2 of this invention. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0034] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0035] In the description of this invention, it should be understood that the orientation or positional relationship indicated by terms such as "above" is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed when in use, or the orientation or positional relationship in which those skilled in the art are usually understood. It is only for the convenience of describing this invention and simplifying the description, and is not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0036] The following provides a detailed description of each example. It should be noted that the order of description of the embodiments below is not intended to limit the preferred order of the embodiments. Furthermore, in the description of this application, the term "comprising" means "including but not limited to". Various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a rigid limitation on the scope of the invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single digits within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any referenced number (fraction or integer) within the indicated range.

[0037] This invention provides a FeCoCr magnetic code disk material, such as... Figure 1 As shown, it includes:

[0038] Base 1;

[0039] FeCoCr thin film layer 2 is located on the surface of substrate 1;

[0040] MgO layer 3 is located on the surface of FeCoCr thin film layer 2 and is away from the substrate 1;

[0041] The thickness of the MgO layer 3 is 2–10 nm.

[0042] It should be noted that the FeCoCr magnetic code disk material of the present invention includes a substrate 1, an FeCoCr thin film layer 2, and an MgO layer 3 stacked sequentially; the thickness of the MgO layer 3 is 2-10 nm; the present invention, through the ingenious structural design of introducing an active metal MgO layer 3 on the surface of the FeCoCr thin film layer 2, can effectively regulate the coercivity and remanence of the FeCo thin film layer by controlling the migration of oxygen elements in the MgO layer at the FeCoCr thin film layer interface, resulting in significant grain refinement and the formation of a higher α phase at the FeCo interface; the present invention, in FeC After introducing an MgO layer 3 onto the surface of the MgO thin film layer 2, compared to the absence of an MgO layer 3, the coercivity of the FeCoCr magnetic code disk material increases from 348 Oe to 397–439 ​​Oe, the remanence increases from 3507 Oe to 6534–8721 Oe, and the remanence ratio increases from 0.71 to 0.76–0.77. The FeCoCr magnetic code disk material of this invention, after introducing the MgO layer, exhibits a remanence increase of up to 86–148%, a coercivity increase of 14.08–26.15%, and a remanence ratio increase of 7.04–8.45%, meeting practical application requirements.

[0043] In some embodiments, the FeCoCr thin film layer is an FeCoCr alloy thin film, which includes Fe, Cr, Co, Mo, and Zr elements. Specifically, the FeCoCr thin film layer includes the following elements in mass fractions: Fe 40-41.5%, Cr 29-30.5%, Co 24-25.5%, Mo 0-4%, and Zr 0-2%.

[0044] In some embodiments, the FeCoCr thin film layer comprises the following elements by mass fraction: Fe 40-41.5%, Cr 29-30.5%, Co 24-25.5%, Mo 1-4%, and Zr 0.5-2%, that is, the FeCoCr thin film layer of the present invention contains a small amount of Mo and Zr elements in addition to Fe, Cr, and Co elements.

[0045] Preferably, the FeCoCr thin film layer comprises the following elements by mass fraction: Fe 41%, Cr 30%, Co 25%, Mo 3%, and Zr 1%.

[0046] In some embodiments, the thickness of the MgO layer 3 is 2 to 10 nm. Specifically, the thickness of the MgO layer 3 is 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, or 10 nm. Preferably, the thickness of the MgO layer 3 is 2 to 5 nm, and more preferably, the thickness of the MgO layer 3 is 5 nm.

[0047] In some embodiments, the thickness of the FeCoCr thin film layer 2 is 50–200 nm. Specifically, the thickness of the FeCoCr thin film layer 2 is 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm, or 200 nm. Preferably, the thickness of the FeCoCr thin film layer 2 is 100 nm.

[0048] In some embodiments, substrate 1 includes any one of a glass substrate, a silicon substrate, and a polymer substrate.

[0049] Specifically, silicon substrates include Si substrates and Si / SiO2 substrates, and substrates can also include inorganic substrates such as SiC substrates; polymer substrates can be organic flexible substrates such as polyethylene substrates, polypropylene substrates, polystyrene substrates, polyethylene terephthalate substrates, polyimide substrates, and polycarbonate substrates.

[0050] Based on the same inventive concept, the present invention also provides a method for preparing the above-mentioned FeCoCr magnetic code disk material, comprising the following steps:

[0051] FeCoCr thin film and MgO layer were sequentially deposited on the substrate, and then annealed to obtain FeCoCr magnetic code disk material.

[0052] The method for preparing FeCoCr magnetic code disk material of the present invention involves depositing an MgO layer into a FeCoCr thin film. Introducing the MgO layer enhances the coercivity of the magnetic code disk material and achieves high remanence, thus meeting the practical application requirements of magnetic encoder disks. The method for preparing FeCoCr magnetic code disk material of the present invention is simple, easy to control, highly efficient, and low in cost. It can increase the coercivity and remanence of the thin film material, providing a scientific basis for the practical application of thin-film magnetic code disks.

[0053] In some embodiments, FeCoCr thin films are deposited using magnetron sputtering with FeCoCr as the target material; wherein the process parameters controlled by magnetron sputtering are: sputtering power 40-50W, and vacuum degree of sputtering chamber 1×10⁻⁶. -5 ~3×10 -5 Pa, working gas is argon, argon pressure is 0.3~0.6Pa.

[0054] Specifically, in the above embodiments, the composition of the FeCoCr target material and the final deposited FeCoCr thin film layer are as follows: for example, the FeCoCr thin film layer includes the following elements by mass fraction: Fe 40-41.5%, Cr 29-30.5%, Co 24-25.5%, Mo 1-4%, and Zr 0.5-2%. Then, the corresponding FeCoCr target material also includes the following elements by mass fraction: Fe 40-41.5%, Cr 29-30.5%, Co 24-25.5%, Mo 1-4%, and Zr 0.5-2%.

[0055] Specifically, the FeCoCr target material mentioned above was prepared using conventional methods such as smelting and powder metallurgy.

[0056] In some embodiments, an MgO layer is deposited using magnetron sputtering with MgO as the target material; wherein the process parameters controlled by magnetron sputtering are: sputtering power 80–120 W, and vacuum degree of the sputtering chamber 1 × 10⁻⁶. -5 ~3×10 -5 Pa, working gas is argon, argon pressure is 0.3~0.6Pa.

[0057] In some embodiments, FeCoCr thin film layer is obtained by DC sputtering of FeCoCr target material, and MgO layer is obtained by radio frequency sputtering of MgO target material.

[0058] In the above embodiments, the thickness of the FeCoCr thin film layer and the MgO layer is controlled by the through-hole sputtering time.

[0059] In some embodiments, after sequentially depositing an FeCoCr thin film layer and an MgO layer on a substrate, the substrate is placed in a vacuum annealing furnace for annealing to obtain the FeCoCr magnetic code disk material. The process parameters controlled during the annealing step are: annealing temperature of 600–700°C, annealing time of 0.5–1 h, and annealing vacuum degree of 1 × 10⁻⁶. -5 ~6×10 -5 Pa.

[0060] In some embodiments, the substrate is cleaned or polished before the FeCoCr thin film layer and MgO layer are deposited sequentially on the substrate.

[0061] Specifically, the cleaning process for the substrate includes: first, ultrasonic cleaning with acetone and alcohol in sequence, then ultrasonic cleaning with deionized water, and finally drying with nitrogen or an oven.

[0062] Based on the same inventive concept, the present invention also provides an application of the above-mentioned FeCoCr magnetic code disk material or the FeCoCr magnetic code disk material prepared by the above-mentioned preparation method in the preparation of magnetic encoders.

[0063] The following detailed embodiments further illustrate the FeCoCr magnetic code disk material and its preparation method of this application. This section further explains the invention in conjunction with specific embodiments, but should not be construed as limiting the invention. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods, and equipment used in this invention are conventional reagents, methods, and equipment in the art.

[0064] Example 1

[0065] This application provides an embodiment of a FeCoCr magnetic code disk material, comprising:

[0066] Base;

[0067] FeCoCr thin film layer, which is located on the substrate surface;

[0068] The MgO layer is located on the surface of the FeCoCr thin film layer and is far from the substrate.

[0069] The thickness of the MgO layer is 2 nm;

[0070] The FeCoCr thin film layer comprises the following elements by mass fraction: Fe 41%, Cr 30%, Co 25%, Mo 3%, and Zr 1%.

[0071] The thickness of the FeCoCr thin film is 100 nm;

[0072] The substrate is a Si substrate with a thickness of 0.2 mm.

[0073] This application also provides a method for preparing the above-mentioned FeCoCr magnetic code disk material, including the following steps:

[0074] S1. The cleaning of the Si substrate specifically includes: first ultrasonic cleaning with acetone and alcohol in sequence, then ultrasonic cleaning with deionized water, and finally drying with nitrogen gas.

[0075] S2. A 100 nm thick FeCoCr thin film was deposited on a Si substrate using magnetron sputtering with FeCoCr as the target material. The process parameters controlled by the magnetron sputtering were: sputtering power 45 W, and vacuum degree of the sputtering chamber 2 × 10⁻⁶. -5 Pa, working gas is argon, argon pressure is 0.4 Pa; FeCoCr target material includes the following elements by mass fraction: Fe 41%, Cr 30%, Co 25%, Mo 3%, Zr 1%;

[0076] S3. A 2 nm thick MgO layer was deposited on the surface of an FeCoCr thin film using magnetron sputtering with MgO as the target material. The process parameters controlled by magnetron sputtering were: sputtering power 100 W, and vacuum degree of the sputtering chamber 2 × 10⁻⁶. -5 Pa, working gas is argon, argon pressure is 0.4 Pa;

[0077] S4. The material with the MgO layer deposited in S3 is placed in a vacuum annealing furnace for annealing to obtain the FeCoCr magnetic code disk material; wherein the process parameters controlled in the annealing step are: annealing temperature 600℃, annealing time 0.5h, and annealing vacuum degree 3×10 -5 Pa.

[0078] Example 2

[0079] This application provides an embodiment of a FeCoCr magnetic code disk material, comprising:

[0080] Base;

[0081] FeCoCr thin film layer, which is located on the substrate surface;

[0082] The MgO layer is located on the surface of the FeCoCr thin film layer and is far from the substrate.

[0083] The thickness of the MgO layer is 5 nm;

[0084] The FeCoCr thin film layer comprises the following elements by mass fraction: Fe 41%, Cr 30%, Co 25%, Mo 3%, and Zr 1%.

[0085] The thickness of the FeCoCr thin film is 100 nm;

[0086] The substrate is a Si substrate with a thickness of 0.2 mm.

[0087] This application also provides a method for preparing the above-mentioned FeCoCr magnetic code disk material, including the following steps:

[0088] S1. The cleaning of the Si substrate specifically includes: first ultrasonic cleaning with acetone and alcohol in sequence, then ultrasonic cleaning with deionized water, and finally drying with nitrogen gas.

[0089] S2. A 100 nm thick FeCoCr thin film was deposited on a Si substrate using magnetron sputtering with FeCoCr as the target material. The process parameters controlled by the magnetron sputtering were: sputtering power 45 W, and vacuum degree of the sputtering chamber 2 × 10⁻⁶. -5 Pa, working gas is argon, argon pressure is 0.4 Pa; FeCoCr target material includes the following elements by mass fraction: Fe 41%, Cr 30%, Co 25%, Mo 3%, Zr 1%;

[0090] S3. A 5 nm thick MgO layer was deposited on the surface of an FeCoCr thin film using magnetron sputtering with MgO as the target material. The process parameters controlled by the magnetron sputtering were: sputtering power 100 W, and vacuum degree of the sputtering chamber 2 × 10⁻⁶. -5 Pa, working gas is argon, argon pressure is 0.4 Pa;

[0091] S4. The material with the MgO layer deposited in S3 is placed in a vacuum annealing furnace for annealing to obtain the FeCoCr magnetic code disk material; wherein the process parameters controlled in the annealing step are: annealing temperature 600℃, annealing time 0.5h, and annealing vacuum degree 3×10 -5 Pa.

[0092] Example 3

[0093] This application provides an embodiment of a FeCoCr magnetic code disk material, comprising:

[0094] Base;

[0095] FeCoCr thin film layer, which is located on the substrate surface;

[0096] The MgO layer is located on the surface of the FeCoCr thin film layer and is far from the substrate.

[0097] The thickness of the MgO layer is 10 nm;

[0098] The FeCoCr thin film layer comprises the following elements by mass fraction: Fe 41%, Cr 30%, Co 25%, Mo 3%, and Zr 1%.

[0099] The thickness of the FeCoCr thin film is 100 nm;

[0100] The substrate is a Si substrate with a thickness of 0.2 mm.

[0101] This application also provides a method for preparing the above-mentioned FeCoCr magnetic code disk material, including the following steps:

[0102] S1. The cleaning of the Si substrate specifically includes: first ultrasonic cleaning with acetone and alcohol in sequence, then ultrasonic cleaning with deionized water, and finally drying with nitrogen gas.

[0103] S2. A 100 nm thick FeCoCr thin film was deposited on a Si substrate using magnetron sputtering with FeCoCr as the target material. The process parameters controlled by the magnetron sputtering were: sputtering power 45 W, and vacuum degree of the sputtering chamber 2 × 10⁻⁶. -5 Pa, working gas is argon, argon pressure is 0.4 Pa; FeCoCr target material includes the following elements by mass fraction: Fe 41%, Cr 30%, Co 25%, Mo 3%, Zr 1%;

[0104] S3. A 10 nm thick MgO layer was deposited on the surface of an FeCoCr thin film using magnetron sputtering with MgO as the target material. The process parameters controlled by the magnetron sputtering were: sputtering power 100 W, and vacuum degree of the sputtering chamber 2 × 10⁻⁶. -5 Pa, working gas is argon, argon pressure is 0.4 Pa;

[0105] S4. The material with the MgO layer deposited in S3 is placed in a vacuum annealing furnace for annealing to obtain the FeCoCr magnetic code disk material; wherein the process parameters controlled in the annealing step are: annealing temperature 600℃, annealing time 0.5h, and annealing vacuum degree 3×10 -5 Pa.

[0106] Comparative Example 1

[0107] This comparative example provides a FeCoCr magnetic code disk material, comprising:

[0108] Base;

[0109] FeCoCr thin film layer, which is located on the substrate surface;

[0110] The MgO layer is located on the surface of the FeCoCr thin film layer and is far from the substrate.

[0111] The thickness of the MgO layer is 15 nm;

[0112] The FeCoCr thin film layer comprises the following elements by mass fraction: Fe 41%, Cr 30%, Co 25%, Mo 3%, and Zr 1%.

[0113] The thickness of the FeCoCr thin film is 100 nm;

[0114] The substrate is a Si substrate with a thickness of 0.2 mm.

[0115] This application also provides a method for preparing the above-mentioned FeCoCr magnetic code disk material, including the following steps:

[0116] S1. The cleaning of the Si substrate specifically includes: first ultrasonic cleaning with acetone and alcohol in sequence, then ultrasonic cleaning with deionized water, and finally drying with nitrogen gas.

[0117] S2. A 100 nm thick FeCoCr thin film was deposited on a Si substrate using magnetron sputtering with FeCoCr as the target material. The process parameters controlled by the magnetron sputtering were: sputtering power 45 W, and vacuum degree of the sputtering chamber 2 × 10⁻⁶. -5 Pa, working gas is argon, argon pressure is 0.4 Pa; FeCoCr target material includes the following elements by mass fraction: Fe 41%, Cr 30%, Co 25%, Mo 3%, Zr 1%;

[0118] S3. A 15 nm thick MgO layer was deposited on the surface of an FeCoCr thin film using magnetron sputtering with MgO as the target material. The process parameters controlled by the magnetron sputtering were: sputtering power 100 W, and vacuum degree of the sputtering chamber 2 × 10⁻⁶. -5 Pa, working gas is argon, argon pressure is 0.4 Pa;

[0119] S4. The material with the MgO layer deposited in S3 is placed in a vacuum annealing furnace for annealing to obtain the FeCoCr magnetic code disk material; wherein the process parameters controlled in the annealing step are: annealing temperature 600℃, annealing time 0.5h, and annealing vacuum degree 3×10 -5 Pa.

[0120] Comparative Example 2

[0121] This comparative example provides a FeCoCr magnetic code disk material, comprising:

[0122] Base;

[0123] FeCoCr thin film layer, which is located on the substrate surface;

[0124] The FeCoCr thin film layer comprises the following elements by mass fraction: Fe 41%, Cr 30%, Co 25%, Mo 3%, and Zr 1%.

[0125] The thickness of the FeCoCr thin film is 100 nm;

[0126] The substrate is a Si substrate with a thickness of 0.2 mm.

[0127] This application also provides a method for preparing the above-mentioned FeCoCr magnetic code disk material, including the following steps:

[0128] S1. The cleaning of the Si substrate specifically includes: first ultrasonic cleaning with acetone and alcohol in sequence, then ultrasonic cleaning with deionized water, and finally drying with nitrogen gas.

[0129] S2. A 100 nm thick FeCoCr thin film was deposited on a Si substrate using magnetron sputtering with FeCoCr as the target material. The process parameters controlled by the magnetron sputtering were: sputtering power 45 W, and vacuum degree of the sputtering chamber 2 × 10⁻⁶. -5 Pa, working gas is argon, argon pressure is 0.4 Pa; FeCoCr target material includes the following elements by mass fraction: Fe 41%, Cr 30%, Co 25%, Mo 3%, Zr 1%;

[0130] S3. The material with the FeCoCr thin film layer deposited in S2 is placed in a vacuum annealing furnace for annealing to obtain the FeCoCr magnetic code disk material; wherein the process parameters controlled in the annealing step are: annealing temperature 600℃, annealing time 0.5h, and annealing vacuum degree 3×10 -5 Pa.

[0131] Performance testing

[0132] The in-plane hysteresis loops of the FeCoCr magnetic code disk materials prepared in Examples 1-3 and Comparative Example 1 were tested, and the results are as follows: Figures 2-5 As shown.

[0133] The magnetic properties of the FeCoCr magnetic code disk materials prepared in Examples 1-3 and Comparative Examples 1-2 are shown in Table 1.

[0134] Table 1 - Magnetic properties of FeCoCr magnetic code disk materials prepared in different embodiments

[0135] Example 1 397 8721 11272 0.77 Example 2 406 8331 11032 0.76 Example 3 439 6534 8482 0.77 Comparative Example 1 321 5642 8884 0.64 Comparative Example 2 348 3507 4940 0.71

[0136] In Table 1, Hc, Mr, Ms, and Mr / Ms represent the coercivity, remanence, magnetization, and remanence ratio of the FeCoCr magnetic code disk material, respectively.

[0137] As shown in Table 1, the FeCoCr magnetic code disk material prepared in Comparative Example 2 does not contain an MgO layer (i.e., the MgO layer thickness is 0 nm). The coercivity of the FeCoCr magnetic code disk material prepared in Comparative Example 2 is 348 Oe, the remanence is 3507 Oe, the magnetization is 4940 Oe, and the remanence ratio is 0.71. The thicknesses of the MgO layer in the FeCoCr magnetic code disk materials prepared in Examples 1-3 are 2 nm, 5 nm, and 10 nm, respectively, and the corresponding coercivity is 3... The magnetization values ​​were 97 Oe, 406 Oe, and 439 Oe, with remanence values ​​of 8721 Oe, 8331 Oe, and 6534 Oe, and magnetization intensities of 11272 Oe, 11032 Oe, and 8482 Oe, respectively. The remanence ratios were 0.77, 0.76, and 0.77, respectively. A comparison of Comparative Example 2 and Examples 1-3 shows that when the MgO layer thickness is 2-10 nm, the coercivity of the prepared FeCoCr magnetic code disk material is improved, and the remanence and remanence ratio are also significantly enhanced. Furthermore, Table 1 shows that when the MgO layer thickness is 15 nm, the coercivity of the prepared FeCoCr magnetic code disk material is lower than that of Comparative Example 2, indicating that the thickness of the MgO layer must be within a certain range to improve the coercivity of the FeCoCr magnetic code disk material.

[0138] Figure 6 The XRD patterns are of the FeCoCr magnetic code disk materials prepared in Examples 1-3 and Comparative Examples 1-2.

[0139] Figure 6 In the figure, 0nm indicates that the thickness of the MgO layer is 0nm, corresponding to a ratio of 2. Figure 6 In this context, 2nm indicates that the thickness of the MgO layer is 2nm, corresponding to Example 1; Figure 6 In this context, 5nm indicates that the thickness of the MgO layer is 5nm, corresponding to Example 2; Figure 6 In this context, 10nm indicates that the thickness of the MgO layer is 10nm, corresponding to Example 3; Figure 6 In the figure, 15nm indicates that the thickness of the MgO layer is 15nm, corresponding to a ratio of 1.

[0140] from Figure 6As can be seen, when the thickness of the MgO layer is 5 nm, a new diffraction peak appears near 36.6° in the prepared FeCoCr magnetic code disk material, which is the diffraction peak of the MgO(111) phase. With the increase of the MgO layer thickness, the diffraction intensity of the MgO(111) phase continuously increases, indicating an increase in the crystallinity of the MgO capping layer. No MgO(111) phase diffraction peak appears when the MgO layer thickness is 2 nm, indicating that no phase is formed. When the MgO layer thickness is 10 nm, a new diffraction peak appears near 43.6°, which appears amorphous based on the peak shape. However, when the MgO layer thickness increases to 15 nm, this peak exhibits better crystallinity. Through comparison with PDF cards, we determined that this peak is the γ-FeCrCo phase. The γ-FeCrCo phase is a harmful phase in FeCrCo alloys; its precipitation will deteriorate the magnetic properties of the FeCrCo alloy, which is consistent with the magnetic test results.

[0141] Figure 6 The diffraction peak appearing at 45° is the α-FeCoCr(110) peak. By fitting the α-FeCoCr(110) peak, the full width at half maximum (FWHM) of the α-FeCoCr(110) phase was obtained. The average grain size of the α-FeCoCr(110) phase in the FeCrCo film was calculated, and the results are as follows: Figure 7 As shown.

[0142] Figure 7 The horizontal axis represents the thickness of the MgO layer. Specifically, 0nm means that the thickness of the MgO layer is 0nm, corresponding to a ratio of 2. Figure 7 In this context, 2nm indicates that the thickness of the MgO layer is 2nm, corresponding to Example 1; Figure 7 In this context, 5nm indicates that the thickness of the MgO layer is 5nm, corresponding to Example 2; Figure 7 In this context, 10nm indicates that the thickness of the MgO layer is 10nm, corresponding to Example 3; Figure 7 In the figure, 15nm indicates that the thickness of the MgO layer is 15nm, corresponding to a ratio of 1.

[0143] from Figure 7As can be seen from the data, in Comparative Example 2, without the MgO layer, the average grain size of the α-FeCoCr(110) phase is 46.147 nm; in Example 1, when the thickness of the MgO layer is 2 nm, the average grain size of the α-FeCoCr(110) phase in the FeCrCo thin film layer decreases to 45.507 nm; thereafter, as the thickness of the MgO layer increases, the average grain size of the α-FeCoCr(110) phase shows a trend of first decreasing and then increasing. When the thickness of the MgO layer is 5 nm, the average grain size of the α-FeCoCr(110) phase reaches its minimum of 40.938 nm, indicating that the introduction of the MgO layer significantly reduces the average grain size of the FeCrCo thin film, promotes grain refinement, and improves the coercivity of the film. However, as the thickness of the MgO layer increases, the average grain size of the α-FeCoCr(110) phase in the FeCrCo thin film increases continuously, but it is still smaller than the average grain size of the FeCrCo thin film without the MgO layer. When the thickness of the MgO layer is 15 nm, the average grain size of the α-FeCoCr(110) phase in the FeCrCo thin film is slightly smaller than the average grain size of the FeCrCo thin film without the MgO layer, but its size is larger than the average grain size of the FeCrCo thin film when the thickness of the MgO layer is 5 nm, resulting in a decrease in its magnetic properties compared to the magnetic code disk material with a 5 nm thick MgO layer.

[0144] In summary, the improvement of the magnetic properties of FeCoCr magnetic code disk material by introducing a MgO layer in this invention is mainly as follows: MgO is an ionic oxide, which has low chemical bond energy and strong reactivity. In magnetron sputtering, MgO is usually under-oxidized after sputtering, resulting in oxidation of the underlying FeCoCr thin film. After sputtering, the film undergoes high-temperature vacuum annealing at 600–700°C. This high-temperature annealing causes oxygen in FeCoCr to migrate upwards to the MgO layer. The reactive metal Mg readily removes oxygen from Fe and Co, reducing the bonding between Fe and oxygen elements. This reduces the oxidation of FeCoCr, leading to the formation of more magnetic phases in the film. The formation of these magnetic phases significantly improves the remanence of the FeCoCr thin film. Furthermore, the introduction of the MgO layer significantly reduces the average grain size of the FeCoCr thin film, promoting grain refinement and improving coercivity. The FeCoCrr magnetic code disk material prepared by this method has high remanence and high remanence ratio, which enables subsequent code disk materials prepared using this structure to have higher comprehensive magnetic properties, providing an important scientific basis for the preparation of novel, high-performance magnetic code disk materials.

[0145] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A FeCoCr magnetic code disk material, characterized in that, include: Base; A FeCoCr thin film layer is located on the surface of the substrate; An MgO layer is located on the surface of the FeCoCr thin film layer and is away from the substrate; The thickness of the MgO layer is 2~10 nm; The preparation method of the FeCoCr magnetic code disk material includes the following steps: FeCoCr thin film layer and MgO layer were sequentially deposited on the substrate, and then annealed to obtain FeCoCr magnetic code disk material; In the annealing step, the annealing temperature is 600~700℃, the annealing time is 0.5~1h, and the annealing vacuum degree is 1×10⁻⁶. -5 ~6×10 -5 Pa.

2. The FeCoCr magnetic code disk material as described in claim 1, characterized in that, The FeCoCr thin film layer is composed of the following elements by mass fraction: Fe 40~41.5%, Cr 29~30.5%, Co 24~25.5%, Mo 0~4%, Zr 0~2%.

3. The FeCoCr magnetic code disk material as described in claim 2, characterized in that, The FeCoCr thin film layer is composed of the following elements by mass fraction: Fe 41%, Cr 30%, Co 25%, Mo 3%, Zr 1%.

4. The FeCoCr magnetic code disk material as described in claim 1, characterized in that, The thickness of the MgO layer is 2~5 nm.

5. The FeCoCr magnetic code disk material as described in claim 1, characterized in that, The thickness of the FeCoCr thin film layer is 50~200nm.

6. The FeCoCr magnetic code disk material as described in claim 1, characterized in that, The substrate includes any one of a glass substrate, a silicon substrate, and a polymer substrate.

7. A method for preparing the FeCoCr magnetic code disk material as described in any one of claims 1 to 6, characterized in that, Includes the following steps: FeCoCr thin film layer and MgO layer were sequentially deposited on the substrate, and then annealed to obtain FeCoCr magnetic code disk material.

8. The method for preparing the FeCoCr magnetic code disk material as described in claim 7, characterized in that, FeCoCr thin films were deposited using magnetron sputtering with FeCoCr as the target material. The process parameters controlled by magnetron sputtering were: sputtering power 40~50W, and vacuum degree of sputtering chamber 1×10⁻⁶. -5 ~3×10 -5 Pa, working gas is argon, argon pressure is 0.3~0.6 Pa; MgO layers were deposited using magnetron sputtering with MgO as the target material. The process parameters controlled by magnetron sputtering were: sputtering power 80~120W, and vacuum degree of sputtering chamber 1×10⁻⁶. -5 ~3×10 -5 Pa, working gas is argon, argon pressure is 0.3~0.6 Pa.

9. The method for preparing the FeCoCr magnetic code disk material as described in claim 7, characterized in that, In the annealing step, the annealing temperature is 600~700℃, the annealing time is 0.5~1h, and the annealing vacuum degree is 1×10⁻⁶. -5 ~6×10 -5 Pa.

10. The application of the FeCoCr magnetic code disk material as described in any one of claims 1 to 6 or the FeCoCr magnetic code disk material prepared by the preparation method as described in any one of claims 7 to 9 in the preparation of magnetic encoders.

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