Hard magnetic material with strong perpendicular anisotropy and preparation and application thereof

Abstract

The present disclosure provides a hard magnetic material with strong perpendicular magnetic anisotropy and preparation and application thereof, a general formula of the hard magnetic material with strong perpendicular magnetic anisotropy is R x A 1‑x BO 2.5 , wherein the R is a lanthanide element; the value of x is within 0.01 to 0.50; the A is selected from the group of group IIA main group elements, and the B is selected from the group of 3d transition metal elements; the atomic structure of the material is an alternately stacked structure of one layer of B-O tetrahedron and one layer of B-O octahedron, observed along the c-axis direction of the crystal structure. The hard magnetic material has strong magnetic anisotropy, and the strong magnetic anisotropy and saturation magnetization of the material can be controllably modulated.

Description

TECHNICAL FIELD

[0001] The present application relates to, but is not limited to, a hard magnetic material with strong perpendicular anisotropy, and in particular to, but is not limited to, a hard magnetic material with strong perpendicular anisotropy and its preparation and application. BACKGROUND

[0002] When magnetized, a ferromagnetic material will exhibit "easy" and "hard" directions, that is, the energy required for the magnetization of the ferromagnetic material will be different depending on the relative direction of the applied magnetic field and the crystal axis, so that the magnetic material exhibits magnetic anisotropy. From a technical and application point of view, magnetic anisotropy is one of the most important characteristics of magnetic materials. Depending on the type of application, materials with different degrees of magnetic anisotropy have their own application fields, such as information magnetic storage media and permanent magnetic materials, etc. Thin film magnetic materials with perpendicular magnetic anisotropy are easy to magnetize along the normal direction of the film surface, and such thin film magnetic materials with perpendicular magnetic anisotropy are of great concern because of their wide application prospects in the field of magnetic recording media. Thin films with magnetic crystal anisotropy are an ideal carrier for realizing perpendicular recording media.

[0003] The existing technology for obtaining a material with perpendicular magnetic anisotropy usually has a multi-layer film of a magnetic transition metal and an oxide, such as the classic out-of-plane magnetization Ta / CoFeB / MgO system; for the oxide system, the twist of the oxygen octahedron also has a significant adjustment effect on the magnetic anisotropy, such as the construction of (La 1-x Sr x MnO3) / (SrIrO3) superlattice, adjusting the La 1- x Sr x MnO3 octahedron twist, thereby realizing perpendicular magnetic anisotropy in the system; applying a compressive stress to the thin film is also an important means of obtaining a thin film with perpendicular magnetic anisotropy, such as growing a La 0.7 Sr 0.3 MnO3 film on a LaAlO3 single crystal substrate; for thin film systems, the magnetic easy axis of the thin film material synthesized by the existing technology is usually in the in-plane direction due to the shape anisotropy effect, and usually does not have strong perpendicular magnetic anisotropy.

[0004] The means of constructing a multi-layer film of a magnetic transition metal and an oxide requires the construction of a multi-layer film structure, which is technically complex; the means of adjusting the twist of the oxygen octahedron in the oxide is limited, and the interface adjustment means including superlattices requires extremely fine thin film growth technology; applying a compressive stress to the thin film requires selecting a suitable single crystal substrate for the thin film, and the single crystal substrates that can provide suitable stress for the thin film are usually limited in type. Moreover, the perpendicular magnetic anisotropy material systems obtained by the above means usually do not have hard magnetic characteristics, and obtaining a material with intrinsic perpendicular magnetic anisotropy has been a continuous effort in the relevant field. SUMMARY

[0005] The following is a summary of subject matter of the detailed description herein. This summary is not intended to limit the scope of the claims.

[0006] In an embodiment of the present disclosure, a hard magnetic material with strong perpendicular magnetic anisotropy is provided, the material has a general formula of R x A 1-x BO 2.5 wherein, the R is a lanthanide element; the value of x is within 0.01 to 0.50;

[0007] the A is selected from the group consisting of Group IIA elements, such as Ca and Sr, etc., and the B is selected from the group consisting of 3d transition metal elements, such as Fe, Co and Ni, etc.

[0008] In the direction of c-axis of the crystal structure, the atomic structure of the material is a structure of alternately stacking one layer of Co-O tetrahedron and one layer of Co-O octahedron (brown iron ore structure).

[0009] In an embodiment of the present disclosure, the material is selected from any one or more of Nd 0.1 Ca 0.9 CoO 2.5 , La 0.1 Ca 0.9 CoO 2.5 , Sm 0.1 Ca 0.9 CoO 2.5 , Gd 0.1 Ca 0.9 CoO 2.5 , Dy 0.1 Ca 0.9 CoO 2.5 , Er 0.1 Ca 0.9 CoO 2.5 and Lu 0.1 Ca 0.9 CoO 2.5 with La doping.

[0010] In an embodiment of the present disclosure, the out-of-plane coercive field strength of the material is 15 kOe to 45 kOe (temperature is 100 K). The in-plane coercive field size measurement exceeds the laboratory conditions (laboratory maximum field 7T).

[0011] In another aspect, in an embodiment of the present disclosure, a preparation method of a hard magnetic material with strong perpendicular magnetic anisotropy is provided, the preparation method comprises:

[0012] using R x A 1-x BO2.5 The target material is formed on the surface of the substrate by any one of physical vapor deposition, chemical vapor deposition, electroplating, vacuum thermal evaporation, vacuum electron beam evaporation, direct current sputtering, magnetron sputtering, radio frequency sputtering, or pulsed laser deposition x A 1-x BO 2.5 .

[0013] In an embodiment provided by the present disclosure, the R x A 1-x BO 2.5 The preparation method of the target material comprises:

[0014] The oxide of R, the oxide of A, and the oxide of B are uniformly mixed in a stoichiometric ratio, and then high-temperature sintering is performed to obtain the target material R x A 1-x BO 2.5 . x A 1-x BO 2.5 The target material;

[0015] In an embodiment provided by the present disclosure, the material of the substrate is selected from any one of the following materials with (001), (110), and (111) orientations.

[0016] In an embodiment provided by the present disclosure, the substrate is selected from (001)-oriented LaAlO3, (001)-oriented (LaAlO3) 0.3 -(SrAl 0.5 Ta 0.5 O3) 0.7 , and (001)-oriented LaSrAlO4, and the like.

[0017] In an embodiment provided by the present disclosure, the epitaxial relationship between the thin film and the substrate is that the c orientation of the brownmillerite structure of the thin film is epitaxial along the substrate Miller index direction.

[0018] In another aspect, the present disclosure provides a method for regulating the saturation magnetization of the hard magnetic material with strong perpendicular magnetic anisotropy as described above, and the method is temperature regulation.

[0019] With the same magnetic field strength, the lower the temperature, the greater the saturation magnetization of the material, and the greater the coercive field.

[0020] With the same temperature, the saturation magnetization is not sensitive to the applied magnetic field strength.

[0021] Adjusting the type of doped rare earth element R used can control the out-of-plane coercive field, wherein the coercive field corresponding to Gd doping is the largest, and increasing or decreasing the atomic number of R will reduce the out-of-plane coercive field.

[0022] Adjusting the type of doped rare earth element R used can control the out-of-plane saturation magnetization, wherein the out-of-plane saturation magnetization of Nd doping is the largest, and increasing or decreasing the atomic number of R will reduce the out-of-plane saturation magnetization.

[0023] In another aspect, the present disclosure provides the use of the above-mentioned material in any one or more of logic devices, memory devices, electromagnetic wave transmitters, electromagnetic wave receivers, magnetic force microscopes, energy storage and storage devices.

[0024] The beneficial effects of the present disclosure relative to the prior art include:

[0025] The present disclosure provides a new type of hard magnetic material with extremely strong perpendicular magnetic anisotropy, provides a new approach to realize the preparation of this type of material, and provides controllable modulation of the strong magnetic anisotropy and saturation magnetization in the material.

[0026] Other features and advantages of the present disclosure will be set forth in the following description, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the present disclosure. Other advantages of the present disclosure can be realized and obtained by means of the schemes described in the specification. BRIEF DESCRIPTION OF DRAWINGS

[0027] The accompanying drawings are used to provide an understanding of the technical solutions of the present disclosure, and constitute a part of the specification, and together with the embodiments of the present disclosure, are used to explain the technical solutions of the present disclosure, and do not constitute a limitation on the technical solutions of the present disclosure.

[0028] Figure 1 The R provided in the present disclosure 0.1 A 0.9 BO 2.5 Atomic structure schematic diagram of

[0029] Figure 2 XRD, 2θ / ω scan of CaCoO 2.5 and Nd 0.1 Ca 0.9 CoO 2.5 thin film on LaAlO3(001) substrate.

[0030] Figure 3 Magnetization (M) of Nd 0.1 Ca 0.9 CoO 2.5 thin film as a function of magnetic field (H) and temperature (T). Figure 3Fig. 2 is a schematic diagram of the test results of the temperature rising process under a magnetic field of 1 kOe after the test 70 kOe from room temperature to 10 K, Figure 3 Fig. 3 corresponds to the test temperature of 100 K.

[0031] Figure 4 R is La, Nd, Sm, Gd, Dy, Er or Lu. 0.1 Ca 0.9 CoO 2.5 Fig. 4 is a curve of the magnetization (M) of the thin film as a function of the magnetic field (H) corresponding to the test temperature of 100 K, wherein R is La, Nd, Sm, Gd, Dy, Er or Lu. DETAILED DESCRIPTION

[0032] In order to make the objects, technical solutions and advantages of the present disclosure clearer, the embodiments of the present disclosure are described in detail below. It should be noted that the embodiments in the present disclosure and the features in the embodiments can be combined with each other arbitrarily without conflict.

[0033] R used in the embodiments and the comparative examples of the present disclosure 0.1 A 0.9 BO 2.5 The preparation method of the target material comprises the following steps:

[0034] The oxide of R, the oxide of A and the oxide of B are uniformly mixed according to the stoichiometric ratio, the mixed powder is pressed according to a certain shape and size, and then sintered at 1200 ℃ in an atmospheric environment for 12 h, and then annealed at a rate of 200 ℃ / h to obtain the target material R x A 1-x BO 2.5 x A 1-x BO 2.5 The target material.

[0035] Embodiment 1:

[0036] A thin film-like ferrimagnetic semiconductor material Nd 0.1 Ca 0.9 CoO 2.5 The atomic structure of the material is shown in Figure 1 Fig. 1, and the grown Nd 0.1 Ca 0.9 CoO 2.5 has a structure of one layer of Co-O tetrahedron and one layer of Co-O octahedron alternately stacking. The Ca ions at the A site are 10% replaced by La ions to present preferred occupation doping.

[0037] The preparation method is to use the components Nd 0.1 Ca 0.9 CoO 2.5 ​Nd 0.1 Ca 0.9 CoO 2.5 thin film. Nd 0.1 Ca 0.9 CoO 2.5 2 nm to 1000 nm. The rest of the doping materials with equal proportion of La-based elements have similar properties.

[0038] Example 2:

[0039] The ferrimagnetic semiconductor material prepared on the LaAlO3(001) substrate using the process method of Example 1 is La 0.1 Ca 0.9 CoO 2.5 (with the same crystal structure as Nd 0.1 Ca 0.9 CoO 2.5 of Example 1), La 0.1 Ca 0.9 CoO 2.5 also has strong perpendicular anisotropy and exhibits hard magnetic properties.

[0040] Example 3:

[0041] The ferrimagnetic semiconductor material prepared on the LaAlO3(001) substrate using the process method of Example 1 is Sm 0.1 Ca 0.9 CoO 2.5 (with the same crystal structure as Nd 0.1 Ca 0.9 CoO 2.5 of Example 1), Sm 0.1 Ca 0.9 CoO 2.5 also has strong perpendicular anisotropy and exhibits hard magnetic properties.

[0042] Example 4:

[0043] The ferrimagnetic semiconductor material prepared on the LaAlO3(001) substrate using the process method of Example 1 is Gd 0.1 Ca 0.9 CoO 2.5 (with the same crystal structure as Nd 0.1 Ca 0.9 CoO 2.5 of Example 1), Gd 0.1 Ca 0.9 CoO 2.5 also has strong perpendicular anisotropy and exhibits hard magnetic properties.

[0044] Example 5:

[0045] The ferrimagnetic semiconductor material prepared on the LaAlO3(001) substrate using the process of Example 1 was Dy 0.1 Ca 0.9 CoO 2.5 (possessing the same crystal structure as Nd 0.1 Ca 0.9 CoO 2.5 (possessing the same crystal structure as Nd 0.1 Ca 0.9 CoO 2.5 also had strong perpendicular anisotropy and exhibited hard magnetic properties.

[0046] Example 6:

[0047] The ferrimagnetic semiconductor material prepared on the LaAlO3(001) substrate using the process of Example 1 was Er 0.1 Ca 0.9 CoO 2.5 (possessing the same crystal structure as Nd 0.1 Ca 0.9 CoO 2.5 (possessing the same crystal structure as Nd 0.1 Ca 0.9 CoO 2.5 also had strong perpendicular anisotropy and exhibited hard magnetic properties.

[0048] Example 7:

[0049] The ferrimagnetic semiconductor material prepared on the LaAlO3(001) substrate using the process of Example 1 was Lu 0.1 Ca 0.9 CoO 2.5 (possessing the same crystal structure as Nd 0.1 Ca 0.9 CoO 2.5 (possessing the same crystal structure as Nd 0.1 Ca 0.9 CoO 2.5 also had strong perpendicular anisotropy and exhibited hard magnetic properties. The remaining doping materials of the same proportion of La-based elements all had similar properties.

[0050] Comparative Example 1:

[0051] The only difference between this comparative example and Example 1 was that the material was changed from Nd 0.1 Ca 0.9 CoO 2.5 to Pr 0.6 Ca 0.4 CoO2.5 The other processes are exactly the same as in Example 1. The resulting product does not possess the corresponding effect. The crystal structure is the same as that of Nd. 0.1 Ca 0.9 CoO 2.5 It does not possess strong vertical anisotropy and hard magnetic properties.

[0052] Comparative Example 2:

[0053] The only difference between the comparative example and Example 1 is that the material is Nd... 0.1 Ca 0.9 CoO 2.5 Change to CaCoO 2.5 The other processes are exactly the same as in Example 1. The resulting product does not possess the corresponding effect. The crystal structure is the same as that of Nd. 0.1 Ca 0.9 CoO 2.5 It does not possess strong vertical anisotropy and hard magnetic properties.

[0054] Figure 2 and Figure 3 All specific experimental data were obtained from Nd2 prepared in Example 1. 0.1 Ca 0.9 CoO 2.5 Thin films, and doped materials of other La-based elements in equal proportions, all exhibit similar properties.

[0055] Using X-ray diffraction (XRD) with a 2θ / ω scan, information about the out-of-plane lattice period of the entire sample can be obtained. For example... Figure 2 As shown, CaCoO3 grown on a LaAlO3(001) substrate 2.5 Thin film, and R after 10% La-based element doping 0.1 Ca 0.9 CoO 2.5 (R = La-based element Nd) thin film. According to the Bragg diffraction formula, the out-of-plane lattice constant changes from 1.504 nm to 1.516 nm after 10% La-based element doping. Considering the larger radius of La ions and the doping effect of the charge itself, this result indicates that the scheme provided in this disclosure successfully produces CaCoO thin films. 2.5 10% La-based element doping was performed, and uniform and high-quality R was obtained. 0.1 Ca 0.9 CoO 2.5 (R = La-based element Nd) thin film.

[0056] R was tested using the Magnetic Comprehensive Testing System (MPMS). 0.1 Ca 0.9 CoO 2.5 The macroscopic magnetic properties of the (R = La-series element Nd) thin film were measured, and the experimental results are as follows:Figure 3 As shown, the material exhibits very strong perpendicular anisotropy. As Figure 3 (b) is the hysteresis loop of the magnetization (M) versus magnetic field (H) at 100 K, with an out-of-plane coercivity of about 35 kOe and a saturation magnetization of about 110 emu / cc, while the in-plane hysteresis loop shows that a field of 70 kOe is still far from saturating the magnetization, the in-plane and out-of-plane hysteresis loop results show that R 0.1 Ca 0.9 CoO 2.5 has very strong perpendicular magnetic anisotropy, and its out-of-plane coercivity of 35 kOe also shows that R 0.1 Ca 0.9 CoO 2.5 is an excellent hard magnetic material. The perpendicular magnetic anisotropy and hard magnetic properties have wide applications in the field of spintronics, magnetic recording media, and permanent magnetic materials. The ferromagnetic transition temperature of the material is shown in Figure 3 (a) to be about 250 K.

[0057] Permanent (hard) magnetic materials are widely used in the design, development, and manufacture of various electronic products, such as DVDs, cameras, sensors, and cell phones. All of these devices include components of permanent magnets, such as the vibration motor in a cell phone. Permanent magnets make the miniaturized design of these devices possible. x A 1-x BO 2.5 is a potential permanent (hard) magnetic material with superior performance, and in low-temperature scenarios, R x A 1-x BO 2.5 The superior hard magnetic properties can also be applied to the above electronic devices as strong magnets.

[0058] In addition, perpendicular magnetic anisotropy materials are one of the best candidates for magnetic storage applications. Compared to traditional random access memory such as dynamic random access memory (DRAM), magnetic random access memory (MRAM) has the characteristics of fast read and write speed, large storage space, strong scalability, ultra-long durability, and non-volatile data storage, which is an important direction of current memory development. Thin films with perpendicular magnetic anisotropy have their magnetic moments parallel to the film normal direction, which has higher storage density than in-plane magnetization materials, and helps to further miniaturize memory devices. Commonly used perpendicular magnetic anisotropy materials include CoFeB / MgO multilayer film structures, but the multilayer film itself has a complex structure, and the R x A 1-x BO 2.5 material has very strong perpendicular magnetic anisotropy in its working temperature range, and its anisotropy is an intrinsic property of the film, which will have broad application prospects in devices such as magnetic random access memory.

Claims

1. A hard magnetic material having a strong perpendicular magnetic anisotropy, characterized by, The general formula of the material is R x A 1-x BO 2.5 wherein the R is a lanthanide element; x has a value within 0.01 to 0.50; The A is selected from the group consisting of elements of the second main group, and the B is selected from the group consisting of 3d transition metals; The atomic structure of the material is a structure in which a layer of B-O tetrahedron and a layer of B-O octahedron are alternately stacked, as viewed along the c-axis direction of the crystal structure.

2. The hard magnetic material having a strong perpendicular magnetic anisotropy according to claim 1, wherein, The material is selected from any one or more of Nd 0.1 Ca 0.9 CoO 2.5 , La 0.1 Ca 0.9 CoO 2.5 , Sm 0.1 Ca 0.9 CoO 2.5 , Gd 0.1 Ca 0.9 CoO 2.5 , Dy 0.1 Ca 0.9 CoO 2.5 , Er 0.1 Ca 0.9 CoO 2.5 , and Lu 0.1 Ca 0.9 CoO 2.5 .

3. The method of producing a hard magnetic material having a strong perpendicular magnetic anisotropy according to claim 1 or 2, characterized in that, The preparation method comprises: Use R x A 1-x BO 2.5 Target material is formed on the surface of the substrate by any one of physical vapor deposition, chemical vapor deposition, electroplating, vacuum thermal evaporation, vacuum electron beam evaporation, direct current sputtering, magnetron sputtering, radio frequency sputtering, or pulsed laser deposition R x A 1-x BO 2.5 .

4. The production method according to claim 3, characterized by, The R x A 1-x BO 2.5 The method for preparing the target material comprises: Will R The oxides of A, A, and B are arranged according to... R x A 1-x BO 2.5 The mixture is homogeneously mixed according to the stoichiometric ratio, and then sintered at high temperature to obtain the desired product. R x A 1-x BO 2.5 Target material.

5. The production method according to claim 3 or 4, characterized by, The material of the substrate is selected from any one of the group consisting of (001), (110) and (111) oriented materials.

6. The production method according to claim 3 or 4, characterized by, The substrate is selected from one or more of YAlO3, SrTiO3, LaAlO3, (LaAlO3) 0.3 -(SrAl 0.5 Ta 0.5 O3) 0.7 and LaSrAlO4.

7. The production method according to claim 3 or 4, characterized by, The epitaxial relationship between the thin film formed by the material and the substrate is that the c direction of the structure of the thin film is epitaxial along the law direction of the substrate.

8. A method of adjusting the saturation magnetization of the hard magnetic material having a strong perpendicular magnetic anisotropy according to claim 1 or 2, characterized by, The method comprises: The saturation magnetization and the coercive field of the material are greater at a lower temperature when the magnetic field strength is constant.

9. Use of the material of claim 1 or 2 in any one or more of logic devices, memory devices, electromagnetic wave emitters, electromagnetic wave receivers, magnetic force microscopes, energy storage and storage devices.

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