阅读说明：本技术 一种掺钐的铋铁氧体纳米材料及其制备方法 (Samarium-doped bismuth ferrite nano material and preparation method thereof ) 是由 张乐 甄方正 邵岑 邱凡 徐嘉厚 陈浩 于 2021-09-30 设计创作，主要内容包括：本发明公开了一种掺钐的铋铁氧体纳米材料及其制备方法,制备方法包括,按照预定的化学计量比将铋源、铁源和钐源溶解在去离子水中,得到混合溶液A；将稀硝酸加入所述混合溶液A中,搅拌,得到混合溶液B；将酒石酸溶解在去离子水中,并添加到混合溶液B中,得到混合溶液C；将混合溶液C加热,得到干燥的凝胶；将凝胶研磨成粉末并煅烧,得到纳米材料。本发明制得的钐掺杂的铋铁氧体纳米材料,平均粒径小,增加了纳米颗粒表面存在的未补偿自旋的密度,从而相比未掺杂的增强了磁化强度,降低了矫顽力,非常适合用于无线充电设备材料。(The invention discloses a samarium-doped bismuth ferrite nano material and a preparation method thereof, wherein the preparation method comprises the steps of dissolving a bismuth source, an iron source and a samarium source in deionized water according to a predetermined stoichiometric ratio to obtain a mixed solution A; adding dilute nitric acid into the mixed solution A, and stirring to obtain a mixed solution B; dissolving tartaric acid in deionized water, and adding the tartaric acid into the mixed solution B to obtain a mixed solution C; heating the mixed solution C to obtain dry gel; the gel is ground into powder and calcined to obtain the nano material. The samarium-doped bismuth ferrite nano material prepared by the invention has small average particle size, increases the density of uncompensated spin on the surface of the nano particle, thereby enhancing the magnetization intensity and reducing the coercive force compared with the undoped bismuth ferrite nano material, and is very suitable for being used as a material of wireless charging equipment.)

1. A preparation method of samarium-doped bismuth ferrite nano-material is characterized by comprising the following steps: comprises the steps of (a) preparing a mixture of a plurality of raw materials,

dissolving a bismuth source, an iron source and a samarium source in deionized water according to a predetermined stoichiometric ratio to obtain a mixed solution A;

adding dilute nitric acid into the mixed solution A, and stirring to obtain a mixed solution B;

dissolving tartaric acid in deionized water, and adding the tartaric acid into the mixed solution B to obtain a mixed solution C;

heating the mixed solution C to obtain dry gel;

the gel is ground into powder and calcined to obtain the nano material.

2. The method of preparing the samarium-doped bismuth ferrite nanomaterial of claim 1, wherein the method comprises: the bismuth source is Bi (NO)₃)₃·5H₂O, the iron source is Fe (NO)₃)₃·9H₂O, the samarium source is Sm (NO)₃)₃·6H₂O；

The molar ratio of the bismuth source to the samarium source to the iron source is (1-x): x: 1; wherein x is more than or equal to 0.1 and less than or equal to 0.2.

3. The method for preparing the samarium-doped bismuth ferrite nano-material of claim 1 or 2, which is characterized in that: the concentration of the dilute nitric acid is 20-30%.

4. The method of preparing the samarium-doped bismuth ferrite nano-material of claim 3, wherein the method comprises the following steps: and adding dilute nitric acid into the mixed solution A, wherein the volume ratio of the dilute nitric acid to the mixed solution A is 0.5-2: 1.

5. the method of preparing the samarium-doped bismuth ferrite nanomaterial of any of claims 1, 2, and 4, wherein: dissolving tartaric acid in deionized water to prepare a solution with the volume fraction of 10-20%.

6. The method of preparing the samarium-doped bismuth ferrite nano-material of claim 5, wherein the method comprises the following steps: and adding the tartaric acid solution into the mixed solution B, wherein the volume ratio of the tartaric acid solution to the mixed solution B is 0.5-2: 1.

7. the method of preparing the samarium-doped bismuth ferrite nanomaterial of any of claims 1, 2, 4, and 6, wherein: and stirring the mixed solution C at 65-90 ℃ for 1-3 h at 300-500 rpm.

8. The method of preparing the samarium-doped bismuth ferrite nanomaterial of claim 7, wherein: and heating the mixed solution C, heating the mixed solution C to 120-130 ℃, and heating for 2-4 h.

9. The method for preparing the samarium-doped bismuth ferrite nano-material of any one of claims 1, 2, 4, 6 and 8, which is characterized in that: and calcining at 550-650 ℃ for 2-4 h.

10. The samarium-doped bismuth ferrite nano-material prepared by the preparation method of any one of claims 1 to 9, which is characterized in that: the chemical formula of the nano material is Bi_1-xSm_xFeO₃Wherein x is more than or equal to 0.1 and less than or equal to 0.2.

Technical Field

The invention belongs to the technical field of magnetized nano materials, and particularly relates to a samarium-doped bismuth ferrite nano material and a preparation method thereof.

Background

Bismuth ferrite is one of the most promising multiferroic materials because it has a wide range of potential applications including microwave systems, satellite communications, storage devices, interactive recording, sensors, spintronic devices, photovoltaic solar cells, and the like. BiFeO₃(BFO) is an interesting multiferroic material because it is at room temperature (Curie temperature T)_C1103K and denier temperature T_N643K) with both ferro and anti-ferromagnetic order. BFO is a rhombohedral twisted perovskite structure (R3c space group) with G-type antiferromagnetic properties. However, synthesizing single-phase ferrite bismuth is not simple because it is stable over a narrow temperature range. Large amounts of BiFeO due to some weaknesses, such as high conductivity, secondary phase formation, weak ferromagnetism, poor magnetoelectric coupling and the presence of oxygen vacancies₃May not be suitable for device applications. Bismuth ferrite is a rhombohedral perovskite structure (R3c space group), and R3c symmetry leads to poor ferromagnetic properties. Furthermore, BFO macroscopic magnetization cannot be observed due to its unfairness of the spiral modulated spin structure (period of 62 nm). Therefore, significant efforts should be made to improve the ferromagnetic characteristics to eliminate the spin helix structure or to increase the anti-parallel spin tilt level. To date, finding ways to minimize current leakage density remains critical.

Valence change of Fe ion (Fe)³⁺/Fe²⁺) Oxygen vacancies and bismuth loss lead to a reduction in current density in BFO. Intrinsic polarization and magnetization of the single Bi at A site³⁺Ion lone pair 6s2 and Fe at B site³⁺Partial filling of the 3d orbits by ions is relevant. With a portion of rare earth ions (e.g. Gd)³⁺、La³⁺、Dy³⁺、Nd³⁺、Eu³⁺And Ho³⁺) Doped BFO has proven to be a successful approach to improve BFO morphology and magnetic performance. Doping can be used to control the physical properties of BFO by causing lattice distortion, controlling evaporation of Bi ions, and making non-centrosymmetric contributions. Furthermore, doping the a-site with different ionic radii can release the trapped magnetization by suppressing the G-type antiferromagnetic spiral modulation.

Therefore, doping proper rare earth metal ions, reducing the Fe-O-Fe angle and increasing the super exchange interaction between two Fe ions is an effective means for improving the magnetic performance.

Disclosure of Invention

This section is for the purpose of summarizing some aspects of embodiments of the invention and to briefly introduce some preferred embodiments. In this section, as well as in the abstract and the title of the invention of this application, simplifications or omissions may be made to avoid obscuring the purpose of the section, the abstract and the title, and such simplifications or omissions are not intended to limit the scope of the invention.

In view of the above and/or the deficiencies in the prior art, the invention provides a samarium-doped bismuth ferrite nano material and a preparation method thereof.

In order to solve the technical problems, the invention provides the following technical scheme: a method for preparing samarium-doped bismuth ferrite nano-material comprises the following steps,

dissolving a bismuth source, an iron source and a samarium source in deionized water according to a predetermined stoichiometric ratio to obtain a mixed solution A;

adding dilute nitric acid into the mixed solution A, and stirring to obtain a mixed solution B;

dissolving tartaric acid in deionized water, and adding the tartaric acid into the mixed solution B to obtain a mixed solution C;

heating the mixed solution C to obtain dry gel;

the gel is ground into powder and calcined to obtain the nano material.

As a preferred scheme of the preparation method of the samarium-doped bismuth ferrite nano material, the preparation method comprises the following steps: the bismuth source is Bi (NO)₃)₃·5H₂O, the iron source is Fe (NO)₃)₃·9H₂O, the samarium source is Sm (NO)₃)₃.6H₂O；

The molar ratio of the bismuth source to the samarium source to the iron source is (1-x): x: 1; wherein x is more than or equal to 0.1 and less than or equal to 0.2.

As a preferred scheme of the preparation method of the samarium-doped bismuth ferrite nano material, the preparation method comprises the following steps: the concentration of the dilute nitric acid is 20-30%.

As a preferred scheme of the preparation method of the samarium-doped bismuth ferrite nano material, the preparation method comprises the following steps: adding dilute nitric acid into the mixed solution A, wherein the volume ratio of the dilute nitric acid to the mixed solution A is 0.5-2: 1.

as a preferred scheme of the preparation method of the samarium-doped bismuth ferrite nano material, the preparation method comprises the following steps: dissolving tartaric acid in deionized water to prepare a solution with the volume fraction of 10-20%.

As a preferred scheme of the preparation method of the samarium-doped bismuth ferrite nano material, the preparation method comprises the following steps: and adding the tartaric acid solution into the mixed solution B, wherein the volume ratio of the tartaric acid solution to the mixed solution B is 0.5-2: 1.

as a preferred scheme of the preparation method of the samarium-doped bismuth ferrite nano material, the preparation method comprises the following steps: and stirring the mixed solution C at 65-90 ℃ for 1-3 h at 300-500 rpm.

As a preferred scheme of the preparation method of the samarium-doped bismuth ferrite nano material, the preparation method comprises the following steps: and heating the mixed solution C, heating the mixed solution C to 120-130 ℃, and heating for 2-4 h.

As a preferred scheme of the preparation method of the samarium-doped bismuth ferrite nano material, the preparation method comprises the following steps: and calcining at 550-650 ℃ for 2-4 h.

Another purpose of the invention is to provide the samarium-doped bismuth ferrite nano material prepared by the preparation method, wherein the chemical formula of the nano material is Bi_1-xSm_xFeO₃Wherein x is more than or equal to 0.1 and less than or equal to 0.2.

Compared with the prior art, the invention has the following beneficial effects:

sm prepared by the invention³⁺The doped bismuth ferrite nano material has small average particle size of 28-38 nm; due to the reduction of the average particle size, the density of uncompensated spins existing on the surface of the nano particles is increased, so that the magnetization intensity is enhanced compared with that of undoped nano particles, the coercive force is reduced, and the nano particles are very suitable for materials of wireless charging equipment.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise. Wherein:

FIG. 1 is an XRD spectrum of the nano-powder prepared in examples 1-5 of the present invention.

Fig. 2 is a particle size distribution and SEM image of the nano-powder prepared in examples 1, 3, 4, and 5 of the present invention.

FIG. 3 is a M-H hysteresis loop of the nano-powder prepared in examples 1-5 of the present invention.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention more comprehensible, specific embodiments thereof are described in detail below with reference to examples of the specification.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those specifically described and will be readily apparent to those of ordinary skill in the art without departing from the spirit of the present invention, and therefore the present invention is not limited to the specific embodiments disclosed below.

Furthermore, reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one implementation of the invention. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

The following examples are all prepared as commercially available polyvinyl alcohol (C) having a purity of greater than 99.9%₂H₄O), nitric acid (HNO)₃)、 Bi(NO₃)₃·5H₂O、Fe(NO₃)₃·9H₂O、Sm(NO₃)₃·6H₂O and C₆H₆O₇As a starting material.

Example 1

(1) According to the chemical formula BiFeO₃Stoichiometric ratio of Bi (NO)₃)₃·5H₂O and Fe (NO)₃)₃·9H₂Dissolving O in deionized water, and stirring for 55min at room temperature by using magnetic force to obtain a mixed solution A;

(2) adding dilute nitric acid with the concentration of 27% into the mixed solution A, wherein the volume ratio of the dilute nitric acid to the mixed solution A is 1:1, and stirring at room temperature for 30-60 min to obtain a mixed solution B;

(3) mixing tartaric acid (C)₆H₆O₇) Dissolving in deionized water to prepare a solution with a volume fraction of 15%, and adding the solution into the mixed solution B, wherein the volume ratio of the tartaric acid solution to the mixed solution B is 1.5: 1, obtaining a mixed solution C.

(4) Stirring the mixed solution C at 80 ℃ for 2h at 300-500 rpm, then heating to 125 ℃, and heating for 2.5h to obtain dry gel;

(5) the gel was ground to a powder and heated at 600 ℃ for 3.5h to give the nanomaterial.

Example 2

(1) According to the chemical formula Bi_0.95Sm_0.05FeO₃Stoichiometric ratio of Bi (NO)₃)₃·5H₂O、 Fe(NO₃)₃·9H₂O and Sm (NO)₃)₃.6H₂Dissolving O in deionized water, and stirring for 55min at room temperature by using magnetic force to obtain a mixed solution A;

(2) adding dilute nitric acid with the concentration of 27% into the mixed solution A, wherein the volume ratio of the dilute nitric acid to the mixed solution A is 1:1, and stirring at room temperature for 30-60 min to obtain a mixed solution B;

(3) mixing tartaric acid (C)₆H₆O₇) Dissolving in deionized water to prepare a solution with a volume fraction of 15%, and adding the solution into the mixed solution B, wherein the volume ratio of the tartaric acid solution to the mixed solution B is 1.5: 1, obtaining a mixed solution C;

(4) stirring the mixed solution C at 80 ℃ for 2h at 300-500 rpm, then heating to 125 ℃, and heating for 2.5h to obtain dry gel;

(5) the gel was ground to a powder and heated at 600 ℃ for 3.5h to give the nanomaterial.

Example 3

(1) According to the chemical formula Bi_0.90Sm_0.10FeO₃Stoichiometric ratio of Bi (NO)₃)₃·5H₂O、 Fe(NO₃)₃·9H₂O and Sm (NO)₃)₃.6H₂Dissolving O in deionized water, and stirring for 60min at room temperature by using magnetic force to obtain a mixed solution A;

(2) adding 20% dilute nitric acid into the mixed solution A, wherein the volume ratio of the dilute nitric acid to the mixed solution A is 2:1, and stirring at room temperature for 30min to obtain a mixed solution B;

(3) mixing tartaric acid (C)₆H₆O₇) Dissolving in deionized water to prepare a solution with the volume fraction of 20%, and adding the solution into the mixed solution B, wherein the volume ratio of the tartaric acid solution to the mixed solution B is 0.5:1, obtaining a mixed solution C;

(4) stirring the mixed solution C at 90 ℃ for 3h at 300rpm, then heating to 120 ℃, and heating for 4h to obtain dried gel;

(5) the gel was ground to a powder and heated at 550 ℃ for 4h to give the nanomaterial.

Example 4

(1) According to the chemical formula Bi_0.85Sm_0.15FeO₃Stoichiometric ratio of Bi (NO)₃)₃·5H₂O、 Fe(NO₃)₃·9H₂O and Sm (NO)₃)₃.6H₂Dissolving O in deionized water, and stirring for 30min at room temperature by using magnetic force to obtain a mixed solution A;

(2) adding 30% dilute nitric acid into the mixed solution A, wherein the volume ratio of the dilute nitric acid to the mixed solution A is 0.5:1, and stirring at room temperature for 60min to obtain a mixed solution B;

(3) mixing tartaric acid (C)₆H₆O₇) Dissolving in deionized water to prepare a solution with the volume fraction of 10%, and adding the solution into the mixed solution B, wherein the volume ratio of the tartaric acid solution to the mixed solution B is 2:1, obtaining a mixed solution C;

(4) stirring the mixed solution C at 65 ℃ for 1h at 500rpm, then heating to 130 ℃, and heating for 2h to obtain dried gel;

(5) the gel was ground to a powder and heated at 650 ℃ for 2h to give the nanomaterial.

Example 5

(1) According to the chemical formula Bi_0.80Sm_0.20FeO₃Stoichiometric ratio of Bi (NO)₃)₃·5H₂O、 Fe(NO₃)₃·9H₂O and Sm (NO)₃)₃.6H₂Dissolving O in deionized water, and stirring for 55min at room temperature by using magnetic force to obtain a mixed solution A;

(2) adding dilute nitric acid with the concentration of 27% into the mixed solution A, wherein the volume ratio of the dilute nitric acid to the mixed solution A is 1:1, and stirring at room temperature for 30-60 min to obtain a mixed solution B;

(3) mixing tartaric acid (C)₆H₆O₇) Dissolving in deionized water to prepare a solution with a volume fraction of 15%, and adding the solution into the mixed solution B, wherein the volume ratio of the tartaric acid solution to the mixed solution B is 1.5: 1, obtaining a mixed solution C;

(4) stirring the mixed solution C at 80 ℃ for 2h at 300-500 rpm, then heating to 125 ℃, and heating for 2.5h to obtain dry gel;

(5) the gel was ground to a powder and heated at 600 ℃ for 3.5h to give the nanomaterial.

XR of nanopowders prepared in examples 1 to 5The D map is shown in figure 1. As can be seen from FIG. 1, pure BiFeO was successfully prepared₃:Sm³⁺The XRD spectrum shows that Sm successfully enters BiFeO₃In the crystal lattice of (1).

The particle size distribution and SEM image of the nanopowders prepared in examples 1, 3, 4 and 5 are shown in fig. 2. As can be seen from the particle size distribution diagram and the SEM image of fig. 2, the average particle size thereof is continuously decreased as the amount of Sm doping is increased.

The magnetic properties of the nano-powder prepared in examples 1 to 5 were tested by using a vibration sample magnetometer and an electron paramagnetic resonance spectrometer. The results are shown in Table 1.

TABLE 1

From the data in Table 1, it can be seen that Sm undoped and lightly Sm doped BiFeO is compared to examples 1, 2₃The nano powder is a nano material with the Sm doping amount of 0.1-0.2, and has high magnetization intensity and low coercive force.

The M-H hysteresis loop of the nano-powder prepared in the examples 1-5 (the testing method is to use a vibrating sample magnetometer and an electron paramagnetic resonance spectrometer for testing) is shown in FIG. 3 a; FIGS. 3b to f are M-H hysteresis loops of the nano-powders prepared in examples 1, 2, 3, 4 and 5, respectively. As can be seen from FIG. 3, Sm-undoped and sparingly Sm-doped BiFeO was compared with examples 1 and 2₃The nano powder is a nano material with the Sm doping amount of 0.1-0.2, and has high magnetization intensity and low coercive force.

It should be noted that the above-mentioned embodiments are only for illustrating the technical solutions of the present invention and not for limiting, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, which should be covered by the claims of the present invention.