BiFeO3 / CoFe2O4 two-dimensional single-crystal heterojunction material, solid-phase sintering method and application

Abstract

The invention discloses a BiFeO3 / CoFe2O4 two-dimensional single-crystal heterojunction multiferroic material, a solid-phase sintering preparation method and application. The solid-phase sintering preparation method comprises the following steps: 1) preparing a solid mixture of single-crystal bismuth ferrite and cobalt ferrite; 2) adding a sodium dodecyl benzene sulfonate solution with a certain concentration into the solid mixture to obtain a reaction material; 3) uniformly mixing the reaction materials by ultrasonic oscillation; 4) putting the vibrated reaction material into a drying oven to remove moisture; the preparation method of the BiFeO3 / CoFe2O4 two-dimensional single crystal heterojunction multiferroic material.Raw materials used in the preparation method are low in toxicity, and the BiFeO3 / CoFe2O4 two-dimensional single crystal heterojunction multiferroic material has the advantages that the BiFeO3 / CoFe2O4 two-dimensional single crystal heterojunction multiferroic material is relatively friendly to the environment and simple in preparation process, large-scale industrial production can be achieved more easily, and the like.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of two-dimensional single-crystal heterojunction materials, in particular to a BiFeO3 / CoFe2O4 two-dimensional single-crystal heterojunction material, a preparation method and application. BACKGROUND

[0002] Bismuth ferrite BiFeO3 (BFO) is the only ferromagnetic material with ferromagnetic and ferroelectric properties at room temperature, and the multi-ferroic property means that it can produce a coupling effect between an electric field and a magnetic field, that is, the magnetism is regulated by changing the electric field, or the polarization is regulated by the magnetic field; and the bismuth ferrite has a high Curie temperature (1103K) and a Niel temperature (643K), so that it is widely applied to the fields of electronic device such as ferroelectric storage equipment and magnetic field sensors. Due to the special structure of the bismuth ferrite, the bismuth ferrite does not exhibit magnetism in the macroscopic aspect, and there is a large leakage current, which seriously restricts the practical application of the bismuth ferrite in electronic devices. Therefore, improving the magnetic properties of the bismuth ferrite has become the focus of attention. SUMMARY

[0003] The purpose of the application is to overcome the deficiencies of the magnetic properties of the ferromagnetic material in the prior art, and provide a BiFeO3 / CoFe2O4 two-dimensional single-crystal heterojunction material, a solid-phase sintering method and application.

[0004] The purpose of the application is achieved by the following technical solutions.

[0005] A solid-phase sintering preparation method of a BiFeO3 / CoFe2O4 two-dimensional single-crystal heterojunction material, comprising the following steps:

[0006] 1) preparing a solid mixture of single-crystal bismuth ferrite and cobalt ferrite;

[0007] 2) adding a sodium dodecyl benzene sulfonate solution with a certain concentration into the solid mixture prepared in step 1) to obtain a reaction material;

[0008] 3) using ultrasonic oscillation on the reaction material prepared in step 2) for 10-30 min;

[0009] 4) transferring the oscillated reaction material into a small porcelain boat, and then placing the small porcelain boat into an oven for drying at 80 DEG C for 2 h to remove water;

[0010] 5) after removing the water, transferring the small porcelain boat into a muffle furnace for sintering at 200-400 DEG C for 10-60 min; high-temperature sintering;

[0011] 6) after high-temperature sintering, cooling to room temperature to obtain the BiFeO3 / CoFe2O4 two-dimensional single-crystal heterojunction multi-ferroic material.

[0012] In the step 1), the preparation of the solid mixture of the single-crystal bismuth ferrite and the cobalt ferrite is as follows: a proper amount of cobalt ferrite and bismuth ferrite single-crystal nanosheets are mixed, and the mass ratio of the cobalt ferrite to the bismuth ferrite single-crystal nanosheets is 6-40:1.

[0013] The concentration of the sodium dodecyl benzene sulfonate solution in the step 2) is 0.001-0.01 mol / L.

[0014] The application provides a BiFeO3 / CoFe2O4 two-dimensional single-crystal heterojunction material prepared by the method, wherein the cobalt ferrite is in a granular or film form and grows on the single-crystal bismuth ferrite nanosheet.

[0015] The application forms a composite multiferroic material by compounding bismuth ferrite BiFeO3 and other multiferroic materials, so that interface coupling effects can be generated between the materials, and the magnetism of the multiferroic material can be effectively improved. The cobalt ferrite CoFe2O4 is a typical ferromagnetic material, has a high Curie temperature and a strong spin polarization, and after being compounded with the bismuth ferrite, the strong magnetism of the cobalt ferrite can be transmitted to the bismuth ferrite BiFeO3 through interaction, and the overall magnetic response is enhanced. In addition, there is interaction between the interfaces of the BiFeO3 and the CoFe2O4, and the interface coupling can promote the rearrangement of electrons and spins, so that the bismuth ferrite can exhibit stronger magnetism under an external magnetic field. The interface effect not only improves the local magnetic order, but also causes the formation of a new phase, thereby enhancing the magnetism.

[0016] The application has the following advantages:

[0017] 1. The bismuth ferrite is compounded with the cobalt ferrite, on the one hand, the cobalt ferrite relies on the bismuth ferrite as a substrate and grows on the surface of the bismuth ferrite to obtain an interface structure, which can promote the rearrangement of electrons and spins, so that the bismuth ferrite can exhibit stronger magnetism under an external magnetic field; on the other hand, the BiFeO3 / CoFe2O4 multiferroic material has a high Curie temperature and Néel temperature, and can effectively solve the application problems of unstable information storage and easy loss of a magnetoelectric storage device at a high temperature;

[0018] 2. In the implementation process of the application, no other impurities are introduced, and the BiFeO3 / CoFe2O4 two-dimensional single-crystal heterojunction multiferroic material can be obtained after sintering.

[0019] 3. In the BiFeO3 / CoFe2O4 two-dimensional single-crystal heterojunction material prepared by the solid-phase sintering method, the bismuth ferrite serves as a substrate material to provide an epitaxial growth condition for the cobalt ferrite, the bismuth ferrite and the cobalt ferrite have good lattice matching degrees, the cobalt ferrite can be in a film form on the single-crystal bismuth ferrite microparticle, and thus the magnetism of the bismuth ferrite is improved.

[0020] 4、The BiFeO3 / CoFe2O4 two-dimensional single-crystal heterojunction material prepared by the solid phase sintering method has low toxicity of raw materials and is relatively friendly to the environment;

[0021] 5、The BiFeO3 / CoFe2O4 two-dimensional single-crystal heterojunction material prepared by the solid phase sintering method has simple preparation process and is easier to realize large-scale industrial production. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is an X-ray diffraction (XRD) spectrum of the BiFeO3 / CoFe2O4 two-dimensional single-crystal heterojunction material prepared in Embodiment 7 of the present application;

[0023] Figure 2 is a scanning electron microscope (SEM) photo of the BiFeO3 / CoFe2O4 two-dimensional single-crystal heterojunction material prepared in Embodiment 7 of the present application;

[0024] Figure 3 is an energy spectrum (EDS) diagram of the BiFeO3 / CoFe2O4 two-dimensional single-crystal heterojunction material prepared in Embodiment 5 of the present application;

[0025] Figure 4 is an M-H hysteresis loop of the BiFeO3 / CoFe2O4 two-dimensional single-crystal heterojunction material prepared in Embodiment 5 of the present application. DETAILED DESCRIPTION

[0026] In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described below in connection with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0027] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present application.

[0028] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0029] It should be noted that like reference numerals and characters refer to like items throughout the drawings and that different items sharing the same reference numeral or character designations do not necessarily share common characteristics unless the context clearly dictates otherwise.

[0030] The BiFeO3 single crystal nanosheet used in the following examples can be prepared by the method authorized by Chinese patent CN102877130B.

[0031] Example 1

[0032] A BiFeO 3 / The method for preparing a CoFe2O4 two-dimensional single crystal heterojunction material comprises the following steps:

[0033] 1) preparing a solid mixture of single crystal bismuth ferrite and cobalt ferrite;

[0034] 2) adding a sodium dodecyl benzene sulfonate solution with a certain concentration to the solid mixture prepared in step 1) to obtain a reaction material;

[0035] 3) using ultrasonic oscillation to treat the reaction material prepared in step 2) for 10-30 min;

[0036] 4) transferring the oscillated reaction material into a small porcelain boat, and then placing the small porcelain boat into an oven for drying at 80°C for 2 h to remove water;

[0037] 5) after removing the water, transferring the small porcelain boat into a muffle furnace for sintering at 200-400°C for 10-60 min; high-temperature sintering;

[0038] 6) after high-temperature sintering, cooling to room temperature to obtain a BiFeO3 / CoFe2O4 two-dimensional single crystal heterojunction multiferroic material.

[0039] In step 1), the preparation of the solid mixture of single crystal bismuth ferrite and cobalt ferrite is as follows: mixing a proper amount of cobalt ferrite and bismuth ferrite single crystal nanosheets, and the mass ratio of the cobalt ferrite and bismuth ferrite single crystal nanosheets is 6-40:1. The cobalt ferrite used in the experiment is a nano cobalt ferrite produced by aladdin company, and its CAS number is 12052-28-7.

[0040] The concentration of the sodium dodecyl benzene sulfonate solution in step 2) is 0.001-0.01 mol / L.

[0041] Example 2

[0042] A BiFeO 3 / The method for preparing a CoFe2O4 two-dimensional single crystal heterojunction material comprises the following steps:

[0043] 1) preparing a solid mixture of single crystal bismuth ferrite and cobalt ferrite;

[0044] 2) adding a sodium dodecyl benzene sulfonate solution with a certain concentration to the solid mixture prepared in step 1) to obtain a reaction material;

[0045] 3) uniformly stirring the reaction material prepared in step 2) by using ultrasonic oscillation;

[0046] 4) transferring the oscillated reaction material to a small porcelain boat, and then placing the small porcelain boat in an oven for drying at 80°C for 2h to remove water;

[0047] 5) after removing the water, transferring the small porcelain boat to a muffle furnace for high-temperature sintering;

[0048] 6) after high-temperature sintering, cooling to room temperature to obtain a BiFeO3 / CoFe2O4 two-dimensional single crystal heterojunction material.

[0049] In the step 1), the preparation of the solid mixture of single crystal bismuth ferrite and cobalt ferrite is as follows: mixing a proper amount of cobalt ferrite and bismuth ferrite single crystal nanosheets, and the mass ratio of the cobalt ferrite and bismuth ferrite single crystal nanosheets is 20:1. The cobalt ferrite used in the experiment is a nanometer cobalt ferrite produced by aladdin company, and the CAS number is 12052-28-7.

[0050] The concentration of the sodium dodecyl benzene sulfonate solution in the step 2) is 0.001 mol / L.

[0051] The ultrasonic oscillation time in the step 3) is 15 min.

[0052] The sintering temperature in the step 6) is 300°C, and the sintering time is 30 min.

[0053] Example 3

[0054] A BiFeO 3 / A preparation method of a CoFe2O4 two-dimensional single crystal heterojunction material, comprising the following steps:

[0055] 1) preparing a solid mixture of single crystal bismuth ferrite and cobalt ferrite;

[0056] 2) adding a sodium dodecyl benzene sulfonate solution with a certain concentration to the solid mixture prepared in step 1) to obtain a reaction material;

[0057] 3) uniformly stirring the reaction material prepared in step 2) by using ultrasonic oscillation;

[0058] 4) transferring the oscillated reaction material to a small porcelain boat, and then placing the small porcelain boat in an oven for drying at 80°C for 2h to remove water;

[0059] 5) after removing the water, transferring the small porcelain boat to a muffle furnace for high-temperature sintering;

[0060] 6) After high-temperature sintering, it is cooled to room temperature to obtain the BiFeO3 / CoFe2O4 two-dimensional single crystal heterojunction material.

[0061] In the step 1), the preparation of the solid mixture of single crystal bismuth ferrite and cobalt ferrite is as follows: a proper amount of cobalt ferrite and bismuth ferrite single crystal nanosheets are mixed, and the mass ratio of the cobalt ferrite and bismuth ferrite single crystal nanosheets is 40:1. The cobalt ferrite used in the experiment is a nanometer cobalt ferrite produced by aladdin company, and its CAS number is 12052-28-7.

[0062] The concentration of the sodium dodecyl benzene sulfonate solution in the step 2) is 0.001 mol / L.

[0063] The ultrasonic oscillation time in the step 3) is 20 min.

[0064] The sintering temperature in the step 6) is 300℃, and the sintering time is 30 min.

[0065] Example 4

[0066] A BiFeO 3 / A method for preparing a CoFe2O4 two-dimensional single crystal heterojunction material, comprising the following steps:

[0067] 1) preparing a solid mixture of single crystal bismuth ferrite and cobalt ferrite;

[0068] 2) adding a sodium dodecyl benzene sulfonate solution with a certain concentration to the solid mixture prepared in step 1) to obtain a reaction material;

[0069] 3) uniformly mixing the reaction material prepared in step 2) by ultrasonic oscillation;

[0070] 4) transferring the oscillated reaction material to a small porcelain boat, and then placing the small porcelain boat in an oven for drying at 80℃ for 2 h to remove water;

[0071] 5) after removing the water, transferring the small porcelain boat to a muffle furnace for high-temperature sintering;

[0072] 6) after high-temperature sintering, cooling it to room temperature to obtain the BiFeO3 / CoFe2O4 two-dimensional single crystal heterojunction material.

[0073] In the step 1), the preparation of the solid mixture of single crystal bismuth ferrite and cobalt ferrite is as follows: a proper amount of cobalt ferrite and bismuth ferrite single crystal nanosheets are mixed, and the mass ratio of the cobalt ferrite and bismuth ferrite single crystal nanosheets is 40:1. The cobalt ferrite used in the experiment is a nanometer cobalt ferrite produced by aladdin company, and its CAS number is 12052-28-7.

[0074] The concentration of the sodium dodecyl benzene sulfonate solution in step 2) is 0.002 mol / L.

[0075] The ultrasonic oscillation time in step 3) is 15 min.

[0076] The sintering temperature in step 6) is 400℃, and the sintering time is 15 min.

[0077] Example 5

[0078] A BiFeO 3 / The preparation method of the CoFe2O4 two-dimensional single crystal heterojunction material comprises the following steps:

[0079] 1) preparing a solid mixture of single crystal bismuth ferrite and cobalt ferrite;

[0080] 2) adding a sodium dodecyl benzene sulfonate solution with a certain concentration to the solid mixture prepared in step 1) to obtain a reaction material;

[0081] 3) uniformly mixing the reaction material prepared in step 2) by ultrasonic oscillation;

[0082] 4) transferring the oscillated reaction material into a small porcelain boat, and then placing the small porcelain boat into an oven for drying at 80℃ for 2 h to remove water;

[0083] 5) after removing the water, transferring the small porcelain boat into a muffle furnace for high-temperature sintering;

[0084] 6) after high-temperature sintering, cooling to room temperature to obtain a BiFeO3 / CoFe2O4 two-dimensional single crystal heterojunction material.

[0085] In step 1), the preparation steps of the solid mixture of single crystal bismuth ferrite and cobalt ferrite are as follows: mixing a proper amount of cobalt ferrite and bismuth ferrite single crystal nanosheets, and the mass ratio of the cobalt ferrite and bismuth ferrite single crystal nanosheets is 8:1. The cobalt ferrite used in the experiment is a nano cobalt ferrite produced by aladdin company, and its CAS number is 12052-28-7.

[0086] The concentration of the sodium dodecyl benzene sulfonate solution in step 2) is 0.005 mol / L.

[0087] The ultrasonic oscillation time in step 3) is 30 min.

[0088] The sintering temperature in step 6) is 250℃, and the sintering time is 45 min.

[0089] The energy spectrum (EDS) analysis of the sample prepared in Example 5 is as follows: Figure 3As shown, it can be seen that Fe, Bi, Co, O elements appear at the detection point, and the particles on the BiFeO3 microparticle can be determined as CoFe2O4 in combination with the XRD result.

[0090] Example 6

[0091] A BiFeO 3 / The preparation method of the CoFe2O4 two-dimensional single crystal heterojunction material comprises the following steps:

[0092] 1) preparing a solid mixture of single crystal bismuth ferrite and cobalt ferrite;

[0093] 2) adding a sodium dodecyl benzene sulfonate solution with a certain concentration to the solid mixture prepared in step 1) to obtain a reaction material;

[0094] 3) uniformly mixing the reaction material prepared in step 2) by ultrasonic oscillation;

[0095] 4) transferring the oscillated reaction material to a small porcelain boat, and then placing the small porcelain boat in an oven for drying at 80℃ for 2h to remove water;

[0096] 5) after removing the water, transferring the small porcelain boat to a muffle furnace for high-temperature sintering;

[0097] 6) after high-temperature sintering, cooling to room temperature to obtain a BiFeO3 / CoFe2O4 two-dimensional single crystal heterojunction material.

[0098] In the step 1), the preparation steps of the solid mixture of single crystal bismuth ferrite and cobalt ferrite are as follows: mixing a proper amount of cobalt ferrite and bismuth ferrite single crystal nanosheets, and the mass ratio of the cobalt ferrite and bismuth ferrite single crystal nanosheets is 40:1. The cobalt ferrite used in the experiment is a nanometer cobalt ferrite produced by aladdin company, and its CAS number is 12052-28-7.

[0099] The concentration of the sodium dodecyl benzene sulfonate solution in the step 2) is 0.01 mol / L.

[0100] The ultrasonic oscillation time in the step 3) is 15 min.

[0101] The sintering temperature in the step 6) is 300℃, and the sintering time is 30 min.

[0102] Example 7

[0103] A BiFeO 3 / The preparation method of the CoFe2O4 two-dimensional single crystal heterojunction material comprises the following steps:

[0104] 1) preparing a solid mixture of single crystal bismuth ferrite and cobalt ferrite;

[0105] 2) adding a sodium dodecyl benzene sulfonate solution with a certain concentration to the solid mixture prepared in step 1) to obtain a reaction material;

[0106] 3) uniformly mixing the reaction material prepared in step 2) by ultrasonic oscillation;

[0107] 4) transferring the oscillated reaction material to a small porcelain boat, and then placing the small porcelain boat in an oven for drying at 80℃ for 2h to remove water;

[0108] 5) after removing the water, transferring the small porcelain boat to a muffle furnace for high-temperature sintering;

[0109] 6) after high-temperature sintering, cooling to room temperature to obtain a BiFeO3 / CoFe2O4 two-dimensional single crystal heterojunction material.

[0110] In step 1), the preparation of the solid mixture of single crystal bismuth ferrite and cobalt ferrite is as follows: mixing a proper amount of cobalt ferrite and bismuth ferrite single crystal nanosheets, and the mass ratio of the cobalt ferrite and bismuth ferrite single crystal nanosheets is 30:1. The cobalt ferrite used in the experiment is a nanometer cobalt ferrite produced by aladdin company, and its CAS number is 12052-28-7.

[0111] The concentration of the sodium dodecyl benzene sulfonate solution in step 2) is 0.003 mol / L.

[0112] The ultrasonic oscillation time in step 3) is 30 min.

[0113] The sintering temperature in step 6) is 350℃, and the sintering time is 20 min.

[0114] The sample prepared in example 7 was characterized by XRD, as shown in Figure 1 The rhombohedral BiFeO3(JCPDS 86-1518) and cubic CoFe2O4(JCPDS 22-1086) can be calibrated in the spectrum, indicating that the BiFeO3 / CoFe2O4 composite multiferroic material is obtained.

[0115] The sample prepared in example 7 was characterized by SEM, as shown in Figure 2 As can be seen from the figure, there are a few granular and strip-shaped materials on the surface of BiFeO3, and the existence of the film can be observed on the surface. Combined with the XRD result, the film on the surface is CoFe2O4.

[0116] Example 8

[0117] The magnetic properties of the BiFeO3 / CoFe2O4 two-dimensional single crystal heterojunction multiferroic material prepared in example 5 were tested, as shown in Figure 4As shown in the figure, the material has a remanent magnetization of 2.942 emu / g and a coercive field of 170.80 Oe, which is significantly improved compared to the magnetic properties of pure BiFeO3 reported in related studies. For example, Yang Xin prepared pure BiFeO3 material, which has a remanent magnetization of only 0.000332 emu / g and a coercive field of 63 Oe (Yang Xin. Zhejiang University [PhD thesis], 2014); Ozdilek C et al. prepared pure BiFeO3 by hydrothermal method, and the obtained material has a remanent magnetization of 0.002 emu / g and a coercive field of 186 Oe, showing weak magnetoelectric coupling effect (Ceramics International, 2020, 46(17):27800); H. Shokrollahi et al. prepared nano BiFeO3 powder by co-precipitation method, and the magnetic property test results show that the material is weakly ferromagnetic, and the coercive force and remanent magnetization are very small (Powder Technology, 2013, 235:953). In addition, the magnetic properties of the sample prepared in the present patent and the BiFeO3 / CoFe2O4 materials prepared in the following prior art are compared as follows: Ge Qingyang prepared BiFeO3 / CoFe2O4 composite material by doctor blade method, which has a remanent magnetization of 1.86 emu / g (Ge Qingyang. Hubei University [Master's thesis], 2024); Dabas S et al. prepared BiFeO3 / CoFe2O4 composite material by solid phase method, which has a remanent magnetization of only 0.1012 emu / g and a coercive field of 740 Oe (Mater Sci:Mater Electron, 2019, 30, 2837); Lin Y et al. synthesized BiFeO3 / CoFe2O4 composite material by sol-gel method, and the magnetic test results show that its remanent polarization is 1.091 emu / g (Mater Sci:Mater Electron, 2015, 26, 1102). In comparison, the BiFeO3 / CoFe2O4 two-dimensional single crystal heterojunction material prepared in the present study exhibits more excellent magnetic properties, showing potential application value as a magnetoelectric storage material.

[0118] Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent replacements to some technical features, and any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A solid-state sintering preparation method for a BiFeO3 / CoFe2O4 two-dimensional single-crystal heterojunction material, characterized in that, Includes the following steps: (1) Preparation of a solid mixture of single-crystal bismuth ferrite and cobalt ferrite; (2) Add a certain concentration of sodium dodecylbenzenesulfonate solution to the solid mixture prepared in step (1) to obtain the reaction material; (3) Vibrate the reaction material prepared in step (2) thoroughly using ultrasonic vibration; (4) Transfer the shaken reaction material to a small ceramic boat for drying; (5) After removing the moisture, transfer the small porcelain boat to a muffle furnace for high-temperature sintering; (6) After high-temperature sintering, cool it to room temperature to obtain BiFeO3 / CoFe2O4 two-dimensional single crystal heterojunction multiferroic material.

2. The solid-state sintering preparation method according to claim 1, characterized in that, In step (1), the preparation steps of the solid mixture of single crystal bismuth ferrite and cobalt ferrite are as follows: weigh an appropriate amount of single crystal nanosheets of cobalt ferrite and bismuth ferrite and mix them, with the mass ratio of single crystal nanosheets of cobalt ferrite and bismuth ferrite being 6~40:

1.

3. The solid-state sintering preparation method according to claim 1, characterized in that, In step (2), the concentration of the sodium dodecylbenzenesulfonate solution is 0.001~0.01mol / L.

4. The solid-state sintering preparation method according to claim 1, characterized in that, In step (3), ultrasonic vibration is used for 10 to 30 minutes.

5. The solid-state sintering preparation method according to claim 1, characterized in that, In step (5), the drying process involves drying at 80°C in an oven for 2 hours to remove moisture.

6. The solid-state sintering preparation method according to claim 1, characterized in that, In step (6), the high-temperature sintering is sintering in a muffle furnace at 200-400°C for 10-60 min.

7. The solid-state sintering preparation method according to claim 1, characterized in that, The remanent magnetization of the BiFeO3 / CoFe2O4 two-dimensional single-crystal heterojunction multiferroic material is 2.942 emu / g, and the coercive field is 170.80 Oe.

8. A BiFeO 3 / CoFe2O4 multiferroic material, characterized by: The material was prepared by solid-state sintering according to any one of claims 1-7.

9. The BiFeO3 / CoFe2O4 two-dimensional single-crystal heterojunction material according to claim 8, characterized in that: in, Cobalt ferrite is grown in particulate and thin film form on single-crystal bismuth ferrite nanosheets.

10. The application of the BiFeO3 / CoFe2O4 two-dimensional single-crystal heterojunction material according to claim 8 or 9 in the fabrication of magnetoelectric storage materials.

Images