FeCoCr thin film, and preparation method and application thereof

Abstract

The application relates to the material field, in particular to a FeCoCr film, a preparation method and application thereof, the FeCoCr film comprises a multilayer structure, the multilayer structure comprises a substrate layer and a FeCoCr layer, and a Pt layer arranged between the substrate layer and the FeCoCr layer; after the Pt layer is introduced, a diffusion reaction occurs between the Pt layer and the FeCoCr layer, thereby generating an L10-FePt phase in the film, forming a new hard magnetic phase, and the coercivity of the FeCoCr film is greatly improved; meanwhile, the Pt element effectively promotes the alpha phase amplitude decomposition in the FeCoCr film into a strong magnetic phase and a Cr-rich non-magnetic phase, the Cr-rich non-magnetic phase plays a role of pinning magnetic domains in the film, and the coercivity of the material is further greatly improved; through the synergistic effect of the two mechanisms, the coercivity of the FeCoCr film is greatly improved, therefore, code disc material prepared by using the FeCoCr film has higher performance, and the code disc signal has higher stability and anti-interference ability after being written.

Description

Technical Field

[0001] This invention belongs to the field of materials, specifically relating to an FeCoCr thin film, its preparation method, and its application. Background Technology

[0002] Currently, optical encoders are primarily used for angle and displacement feedback in high-end CNC machine tools and robot systems to control precision. High-precision encoders are also essential for high-precision measurement and control in major equipment applications. However, because the code disk material is optical glass, it is fragile, easily worn, and susceptible to high temperatures and dust. Magnetic encoders overcome these shortcomings, possessing excellent characteristics such as vibration resistance, corrosion and pollution resistance, low cost, and simple structure, leading to their increasing application. The core of a magnetic encoder is a magnetic code disk material with excellent magnetic properties. The uniformity of the magnetic code disk material has a significant impact on the accuracy of the magnetic encoder and the stability of the recorded magnetic signal.

[0003] Recently, novel magnetic code disk thin film materials have gradually attracted attention. Currently, commonly used magnetic code disk materials include ferrite bulk materials or FeCoCr and CuNiFe tapes. Among them, FeCoCr thin films generally have very low coercivity in single-layer films, which does not meet the practical application requirements of magnetic code disks. This is mainly because it is difficult to obtain a good amplitude-modulated decomposition phase distribution in the material. In fact, the more thorough the decomposition of the strong magnetic phase and the Cr-rich non-magnetic phase, the better, which is conducive to improving the magnetic properties of the thin film. Therefore, FeCoCr thin films directly affect the magnetic energy product and the magnetic material's resistance to external disturbances due to their coercivity.

[0004] Therefore, how to improve the coercivity of FeCoCr magnetic code disk thin film material has always been one of the key issues in the field of magnetic thin film research. Summary of the Invention

[0005] The purpose of this invention is to provide an FeCoCr thin film, its preparation method and application, with the aim of providing an FeCoCr thin film with high coercivity.

[0006] To achieve the above objectives, the present invention provides an FeCoCr thin film comprising a multilayer structure, the multilayer structure comprising a substrate layer and an FeCoCr layer, and a Pt layer disposed between the substrate layer and the FeCoCr layer.

[0007] Optionally, the thickness of the Pt layer is 6–10 nm; and / or, the thickness of the FeCoCr layer is 90–110 nm.

[0008] Optionally, the substrate layer includes a silicon substrate.

[0009] The present invention also provides an FeCoCr thin film, wherein the preparation method of the FeCoCr thin film includes the following steps:

[0010] S10, provides Pt and FeCoCr sputtering targets;

[0011] S20. Using magnetron sputtering, Pt target and FeCoCr target are sequentially deposited on the substrate to form a multilayer film.

[0012] S30. The multilayer film is subjected to vacuum heat treatment to obtain FeCoCr thin film.

[0013] Optionally, step S10 includes cleaning and drying the Pt and FeCoCr targets.

[0014] Optionally, in step S20, the magnetron sputtering deposition step includes:

[0015] The working gas for the magnetron sputtering is argon; and / or...

[0016] The magnetron sputtering power is 70–150 W; and / or,

[0017] The working gas pressure for the magnetron sputtering is 0.3–0.6 Pa; and / or,

[0018] The magnetron sputtering speed is 0.008–0.012 nm / s, and the magnetron sputtering time is 5–6 h.

[0019] Optionally, in step S30, the temperature of the vacuum heat treatment is 600-700°C; and / or the heat treatment time is 0.3-0.7 h.

[0020] Optionally, in step S30, the vacuum degree of the vacuum heat treatment is 1×10⁻⁵ to 5×10⁻⁵ Pa.

[0021] Furthermore, the present invention provides a magnetic code component, the magnetic code component comprising the FeCoCr thin film described above or the FeCoCr thin film prepared by the method described above.

[0022] In the technical solution of this invention, a Pt layer is introduced into the multilayer structure of the FeCoCr thin film. Due to the diffusion reaction between the Pt layer and the FeCoCr layer, the Pt element combines with the Fe element, thereby generating the L10-FePt phase in the film, forming a new hard magnetic phase. This significantly improves the coercivity of the FeCoCr thin film. At the same time, the Pt element effectively promotes the amplitude modulation decomposition of the α phase inside the FeCoCr thin film into a strongly magnetic phase and a Cr-rich non-magnetic phase. The Cr-rich non-magnetic phase acts as a pinning magnetic domain inside the film, thus further significantly improving the coercivity of the material. Through the synergistic effect of the above two mechanisms, the coercivity of the FeCoCr thin film is greatly improved. Therefore, the code disk material prepared using the FeCoCr thin film has higher performance, and the code disk signal has higher stability and resistance to external interference after writing. Attached Figure Description

[0023] 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 related drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 These are hysteresis loop test diagrams for Example 1 and Comparative Example 1;

[0025] Figure 2 The images show the XRD patterns of the magnetic thin films in Example 1 and Comparative Example 1.

[0026] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them.

[0028] It should be noted that, unless specific conditions are specified in the embodiments, conventional conditions or conditions recommended by the manufacturer should be followed. Reagents or instruments whose manufacturers are not specified are all commercially available products. Furthermore, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution that simultaneously satisfies A and B. In addition, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, such a combination should be considered non-existent and not within the scope of protection claimed by this invention. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention.

[0029] Currently, commonly used magnetic code disk materials include ferrite bulk materials or FeCoCr and CuNiFe tapes. The uniformity of the magnetic code disk material has a significant impact on the accuracy of the magnetic encoder and the stability of the recorded magnetic signal. Recently, novel magnetic code disk thin film materials have gradually attracted attention. Since coercivity directly affects the magnetic energy product and the magnetic material's resistance to external disturbances, it is an important performance indicator of magnetic materials. How to improve the coercivity of magnetic thin films for magnetic code disks has always been one of the key issues in the field of magnetic thin film research.

[0030] In view of this, the present invention provides an FeCoCr thin film comprising a multilayer structure, the multilayer structure comprising a substrate layer and an FeCoCr layer, and a Pt layer disposed between the substrate layer and the FeCoCr layer.

[0031] In the technical solution of this invention, a Pt layer is introduced into the multilayer structure of the FeCoCr thin film. Due to the diffusion reaction between the Pt layer and the FeCoCr layer, the Pt element combines with the Fe element, thereby generating the L10-FePt phase in the film, forming a new hard magnetic phase. This significantly improves the coercivity of the FeCoCr thin film. At the same time, the Pt element effectively promotes the amplitude modulation decomposition of the α phase inside the FeCoCr thin film into a strongly magnetic phase and a Cr-rich non-magnetic phase. The Cr-rich non-magnetic phase acts as a pinning magnetic domain inside the film, thus further significantly improving the coercivity of the material. Through the synergistic effect of the above two mechanisms, the coercivity of the FeCoCr thin film is greatly improved. Therefore, the code disk material prepared using the FeCoCr thin film has higher performance, and the code disk signal has higher stability and resistance to external interference after writing.

[0032] Furthermore, the thickness of the Pt layer is 6 to 10 nm, for example, it can be 6 nm, 7 nm, 8 nm, 9 nm, or 10 nm. Within this range, the FeCoCr thin film prepared with the obtained Pt layer thickness has the best effect. This is because if the Pt layer is too thick, the precious metal is relatively expensive, and the production cost is high. However, if the Pt layer is too thin, it is not conducive to the formation of the L10-FePt phase in the FeCoCr thin film, and the improvement in coercivity is not as significant.

[0033] Furthermore, the thickness of the FeCoCr layer is 90–110 nm, for example, it can be 90 nm, 80 nm, 100 nm, or 110 nm. Within this range, the FeCoCr thin film has the best performance. If it is too thick, the film stress will be too high, which will reduce the magnetic properties and the bonding force with the substrate will be poor. If it is too thin, the surface magnetic intensity of the subsequent code disk will be low, the output sine wave signal will be too weak, which is not conducive to the sensor reading head's detection of the code disk signal.

[0034] Furthermore, the substrate layer includes a silicon substrate.

[0035] It should be noted that the substrate layer serves to support the magnetic thin film. Under this premise, the substrate layer is usually selected from materials that do not affect the magnetic properties of the magnetic thin film, such as silicon, aluminum alloy, etc. The thickness of the substrate layer is also not limited and can be flexibly selected according to the needs of the applied equipment. The shape of the substrate layer is also not limited; when the substrate layer is circular, it is a magnetic code disk structure; when the substrate layer is elongated, it is a magnetic code ruler.

[0036] The present invention also provides an FeCoCr thin film, wherein the preparation method of the FeCoCr thin film includes the following steps:

[0037] S10, provides Pt and FeCoCr sputtering targets;

[0038] Furthermore, before step S10, the process includes cleaning and drying the Pt and FeCoCr targets. This is mainly to remove impurities and prevent the presence of debris or other dopants, so that atoms can be directly deposited onto the substrate during sputtering, thus avoiding impurities interfering with the magnetism.

[0039] S20. Using magnetron sputtering, Pt target and FeCoCr target are sequentially deposited on the substrate to form a multilayer film by depositing Pt layer and FeCoCr layer sequentially.

[0040] Further, in step S20, the magnetron sputtering deposition step includes: the working gas for magnetron sputtering is argon; and / or, the sputtering power of the magnetron sputtering is 70-150 W; and / or, the pressure of the working gas for magnetron sputtering is 0.3-0.6 Pa; and / or, the magnetron sputtering velocity is 0.008-0.012 nm / s, and the magnetron sputtering time is 5-6 h.

[0041] It should be noted that the magnetron sputtering conditions can be adjusted according to the equipment's requirements for the thin film. In some embodiments, the magnetron sputtering is radio frequency sputtering, and the working gas for the magnetron sputtering is argon.

[0042] Specifically, the sputtering power of the magnetron sputtering is 70–150 W, for example, 70 W, 80 W, 100 W, 150 W, etc.; the working gas pressure of the magnetron sputtering is 0.3–0.6 Pa, for example, 0.3 Pa, 0.4 Pa, 0.5 Pa, 0.6 Pa; the magnetron sputtering velocity is 0.008–0.012 nm / s, for example, 0.008 nm / s, 0.009 nm / s, 0.0011 nm / s, and 0.0012 nm / s; and the magnetron sputtering time is 5 h–6 h, for example, 5 h, 5.5 h, or 6 h, etc. Within this range, the thickness of the magnetic thin film can be better controlled.

[0043] S30. The multilayer film is subjected to vacuum heat treatment to obtain an FeCoCr thin film.

[0044] Furthermore, in step S30, the vacuum degree of the vacuum heat treatment is 1×10-5 to 5×10-5 Pa, for example, it can be 2×10-5 Pa, 4×10-5 Pa, or 5×10-5 Pa. Within this vacuum degree range, after argon gas is introduced into the vacuum, it can be ionized, and the atoms on the target material can be stripped off and sputtered onto the thin film, thereby preparing various layer structures.

[0045] Furthermore, in the vacuum heat treatment step, the heat treatment temperature is 600–700°C; and / or, the heat treatment time is 0.3–0.7 h.

[0046] Specifically, the heat treatment temperature can be 600℃, 650℃ or 700℃, and the heat treatment time can be 0.3h, 0.5h or 0.7h. Using the heat treatment conditions within the above range can increase the hysteresis of the FeCoCr thin film.

[0047] In addition, the present invention also provides a magnetic code component, the magnetic code component comprising the above-mentioned FeCoCr thin film.

[0048] This invention prepares magnetic code components by adding the above-mentioned FeCoCr thin film, and writes magnetic signals to obtain different magnetic code components, which can be used as signal storage and feedback components for different situations.

[0049] It should be noted that the magnetic encoder assembly mainly consists of a magnetic code disk, a magnetic sensor, and a main structure. As the core component of the magnetic encoder, the magnetic code disk provides the magnetic signal through tiny written magnetic poles. Since the resolution of the magnetic encoder is highly dependent on the uniformity and magnetic properties of the magnetic code disk material, the thin film material used in the code disk needs to possess a certain degree of coercivity to ensure the written magnetic pole signal has strong resistance to external disturbances. However, excessive coercivity increases the difficulty of writing the magnetic pole signal. Therefore, higher requirements are placed on the coercivity of the magnetic code disk material: it cannot be too high or too low, generally between 500 Oe and 3000 Oe is suitable.

[0050] The technical solution of the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings. It should be understood that the following embodiments are only used to explain the present invention and are not intended to limit the present invention.

[0051] Example 1

[0052] A FeCoCr thin film, the multilayer structure including a substrate layer and an FeCoCr layer, and a Pt layer disposed between the substrate layer and the FeCoCr layer, wherein the substrate layer is a silicon substrate, the thickness of the Pt layer is 8 nm, and the thickness of the FeCoCr layer is 100 nm.

[0053] Example 2

[0054] A FeCoCr thin film, the multilayer structure comprising a substrate layer and an FeCoCr layer, and a Pt layer disposed between the substrate layer and the FeCoCr layer, wherein the substrate layer is a silicon substrate, the Pt layer has a thickness of 6 nm, and the FeCoCr layer has a thickness of 90 nm.

[0055] Example 3

[0056] A FeCoCr thin film, the multilayer structure including a substrate layer and an FeCoCr layer, and a Pt layer disposed between the substrate layer and the FeCoCr layer, wherein the substrate layer is a silicon substrate, the thickness of the Pt layer is 10 nm, and the thickness of the FeCoCr layer is 110 nm.

[0057] Example 4

[0058] A FeCoCr thin film, the multilayer structure including a substrate layer and an FeCoCr layer, and a Pt layer disposed between the substrate layer and the FeCoCr layer, wherein the substrate layer is a silicon substrate, the thickness of the Pt layer is 5 nm, and the thickness of the FeCoCr layer is 80 nm.

[0059] Example 5

[0060] A method for preparing FeCoCr thin films includes the following steps:

[0061] S10. Clean and dry the Pt and FeCoCr targets;

[0062] S20. Magnetron sputtering is used, wherein the sputtering conditions include: sputtering for 5.5 hours at a sputtering power of 100W, a working gas pressure of 0.5Pa, and a sputtering speed of 0.0010nm / s, and Pt target and FeCoCr target are sequentially deposited on the silicon substrate to form a multilayer film.

[0063] S30. The multilayer film is subjected to vacuum heat treatment to obtain FeCoCr thin film, wherein the vacuum degree of the vacuum environment is 1×10-5 Pa, the heat treatment temperature is 600℃, and the holding time is 0.3h.

[0064] Example 6

[0065] A method for preparing FeCoCr thin films includes the following steps:

[0066] S10. Clean and dry the Pt and FeCoCr targets;

[0067] S20. Magnetron sputtering is used, wherein the sputtering conditions include: sputtering for 5.5 hours at a sputtering power of 100W, a working gas pressure of 0.5Pa, and a sputtering speed of 0.0010nm / s, and Pt target and FeCoCr target are sequentially deposited on the silicon substrate to form a multilayer film.

[0068] S30. The multilayer film is subjected to vacuum heat treatment to obtain FeCoCr thin film, wherein the vacuum degree of the vacuum environment is 1×10-5~5×10-5 Pa, the heat treatment temperature is 650℃, and the holding time is 0.5h.

[0069] Example 7

[0070] A method for preparing FeCoCr thin films includes the following steps:

[0071] S10. Clean and dry the Pt and FeCoCr targets;

[0072] S20. Magnetron sputtering is used, wherein the sputtering conditions include: sputtering for 5.5 hours at a sputtering power of 100W, a working gas pressure of 0.5Pa, and a sputtering speed of 0.0010nm / s, and Pt target and FeCoCr target are sequentially deposited on the silicon substrate to form a multilayer film.

[0073] S30. The multilayer film is subjected to vacuum heat treatment to obtain FeCoCr thin film, wherein the vacuum degree of the vacuum environment is 1×10-5~5×10-5 Pa, the heat treatment temperature is 650℃, and the holding time is 0.5h.

[0074] Comparative Example 1

[0075] The Pt layer is omitted, and a FeCoCr thin film is provided. The multilayer structure includes a substrate layer and a FeCoCr layer, and the rest is the same as in Example 1.

[0076] Test Examples

[0077] The test results for Examples 1-7 and Comparative Example 1 are shown in Table 1:

[0078] Table 1: Test results of magnetic properties of Examples 1-7 and Comparative Example 1

[0079] Coercivity (Oe) Example 1 945 Example 2 930 Example 3 935 Example 4 924 Example 5 926 Example 6 940 Example 7 945 Comparative Example 1 380

[0080] The MH curves of Example 1 and Comparative Example 1 are as follows: Figure 1 As shown: Figure 1 (a) and (b) are the MH curves of FeCoCr films prepared before and after the introduction of the Pt substrate, respectively. As can be seen from the figure, the coercivity of the film is significantly improved after the introduction of the Pt substrate. The coercivity of the film sample before the introduction of the Pt substrate is only 380 Oe, while the coercivity of the film after the introduction of the Pt substrate can reach 945 Oe, with a coercivity increase of about 150%.

[0081] The XRD patterns of the FeCoCr thin films of Example 1 and Comparative Example 1 are as follows: Figure 2 As shown in the figure, before the introduction of the Pt underlayer, the film contains only a peak of the α phase with a BCC structure. After the introduction of the Pt underlayer, amplitude modulation decomposition occurs in the film, and the α phase with the BCC structure decomposes into a Cr-rich nonmagnetic phase. This nonmagnetic phase acts as a pinning agent for magnetic domains, promoting the improvement of coercivity. Furthermore, and more importantly, a peak of the L10-FePt hard magnetic phase also appears in the film. This iron-platinum phase is a hard magnetic material with high coercivity, thus playing a significant role in improving coercivity.

[0082] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the patent protection scope of the present invention.

Claims

1. A FeCoCr thin film, characterized in that, The FeCoCr film comprises a multi-layer structure, the multi-layer structure comprises a substrate layer and a FeCoCr layer, and a Pt layer arranged between the substrate layer and the FeCoCr layer, wherein the Pt element is combined with the Fe element to generate an L10-FePt phase in the FeCoCr film, a new hard magnetic phase is formed, the thickness of the Pt layer is 6-10 nm; the thickness of the FeCoCr layer is 90-110 nm.

2. The FeCoCr film according to claim 1, wherein the substrate layer comprises a silicon substrate. The substrate layer comprises a silicon substrate.

3. A method of producing the FeCoCr thin film according to any one of claims 1 to 2, characterized by, The method comprises the following steps: S10, providing a Pt target and a FeCoCr target; S20, using a magnetron sputtering method to deposit a Pt layer and a FeCoCr layer on the substrate layer in sequence to obtain a multi-layer film; S30, vacuum heat treating the multi-layer film to obtain the FeCoCr film.

4. The method for preparing the FeCoCr film according to claim 3, wherein before step S10, the Pt target and the FeCoCr target are cleaned and dried. In step S20, the magnetron sputtering step comprises:

5. The method of claim 3, wherein the FeCoCr thin film is prepared by sputtering. The working gas of the magnetron sputtering is argon; and / or, The sputtering power of the magnetron sputtering is 70-150 W; and / or, The gas pressure of the working gas of the magnetron sputtering is 0.3-0.6 Pa; and / or, The speed of the magnetron sputtering is 0.008-0.012 nm / s, and the magnetron sputtering time is 5-6 h. In step S30, in the vacuum heat treating step, 6. The method of claim 3, wherein the FeCoCr thin film is prepared by sputtering a target of FeCoCr alloy. The heat treating temperature is 600-700 DEG C; and / or, The heat treating time is 0.3-0.7 h. The magnetic code assembly comprises the FeCoCr film according to any one of claims 1-2 or the FeCoCr film prepared by the method according to any one of claims 3-7.

7. The method of claim 3, wherein the FeCoCr thin film is prepared by sputtering a target of FeCoCr alloy. In step S30, the vacuum degree of the vacuum heat treatment is 1 x 10 -5 5 x 10 -5 Pa.

8. A magnetic code assembly, characterized by ​

Images