阅读说明：本技术 多阶有序钙钛矿PbHg3Ti4O12晶体及其制备方法 (Multi-order ordered perovskite PbHg3Ti4O12Crystal and method for producing same ) 是由 靳常青 赵建发 李文敏 曹立朋 望贤成 于润泽 于 2019-03-04 设计创作，主要内容包括：本发明提供一种多阶有序钙钛矿PbHg<Sub>3</Sub>Ti<Sub>4</Sub>O<Sub>12</Sub>晶体,其中,使用Cu靶Kα衍射,其以2θ角度表示的X射线粉末衍射图谱在22.98、32.72、40.36、46.95、52.90和58.41处具有衍射峰,2θ角度测量误差为±0.01。本发明还提供一种制备本发明的PbHg<Sub>3</Sub>Ti<Sub>4</Sub>O<Sub>12</Sub>晶体的方法,包括如下步骤：(1)将PbO<Sub>2</Sub>、HgO和TiO<Sub>2</Sub>以1:3:4的摩尔比例充分研磨；(2)将步骤(1)得到的粉末密封包裹后,进行烧结,得到PbHg<Sub>3</Sub>Ti<Sub>4</Sub>O<Sub>12</Sub>晶体。本发明的PbHg<Sub>3</Sub>Ti<Sub>4</Sub>O<Sub>12</Sub>晶体对研究磁电演生等物理现象提供了很好的材料基础,是一种潜在的介电材料,对强关联体系研究具有重要的物理意义。(The invention provides a multi-order perovskite PbHg 3 Ti 4 O 12 A crystal in which an X-ray powder diffraction pattern expressed in terms of 2 theta angles thereof using a Cu target K α diffraction has diffraction peaks at 22.98, 32.72, 40.36, 46.95, 52.90 and 58.41 with a 2 theta angle measurement error of ± 0.01, and a method for preparing PbHg of the present invention 3 Ti 4 O 12 A method of crystallizing comprising the steps of: (1) mixing PbO 2 HgO and TiO 2 Fully grinding according to the molar ratio of 1:3: 4; (2) sealing and wrapping the powder obtained in the step (1), and sintering to obtain PbHg 3 Ti 4 O 12 And (4) crystals. PbHg of the present invention 3 Ti 4 O 12 The crystal provides a good material basis for researching physical phenomena such as magnetoelectricity evolution and the like, is a potential dielectric material, and has important physical significance for the research of strongly-associated systems.)

1. Multi-order ordered perovskite PbHg₃Ti₄O₁₂A crystal wherein, using Cu target K α diffraction, its X-ray powder diffraction pattern expressed in 2 θ angles has diffraction peaks at 22.98, 32.72, 40.36, 46.95, 52.90 and 58.41 with 2 θ angle measurement error of ± 0.01.

2. The crystal of claim 1, wherein an X-ray powder diffraction pattern expressed in 2-theta angles using Cu target ka diffraction has diffraction peaks at 68.58, 73.39, 78.08, 82.70, 87.26, 91.81, and 96.37 with a 2-theta angle measurement error of ± 0.01.

3. The crystal of claim 1, wherein the PbHg is₃Ti₄O₁₂The crystal is cubic system, space group is Im-3(NO.204), and lattice constantThe coordinates of each atom in the unit cell are Pb (0,0,0), Hg (0,0.5,0.5), Ti (0.25,0.25,0.25), O (0,0.7028, 0.2176).

4. Preparation of the multi-order ordered perovskite PbHg as defined in claim 1₃Ti₄O₁₂A method of crystallizing comprising the steps of:

(1) mixing PbO₂HgO and TiO₂Fully grinding according to the molar ratio of 1:3: 4;

(2) sealing and wrapping the powder obtained in the step (1), and sintering to obtain PbHg₃Ti₄O₁₂And (4) crystals.

5. The method of claim 4, wherein the sealing and wrapping of step (2) is performed by a method comprising: pressing the powder obtained in the step (1) into a cylindrical sample, and hermetically wrapping the cylindrical sample by using a gold foil.

6. The method of claim 4, wherein the step (2) further comprises the step of sanding the sintered sample on sandpaper to remove the gold foil on the surface of the sample.

7. The method according to claim 4, wherein the sintering in the step (2) is carried out at a temperature of 500-1400 ℃ and at a pressure of 2-8 GPa.

8. The method according to claim 4, wherein the sintering in step (2) is performed for 0.1-6 h.

Technical Field

The invention belongs to the field of materials. In particular, the invention relates to a multi-order perovskite PbH g₃Ti₄O₁₂Crystals and a method for producing the same.

Background

Having ABO₃Strongly associated electron systems of perovskite or similar structures are an important leading area for condensed state physical studies. In this structure, the a site is often occupied by nonmagnetic alkaline earth, alkali metal, or rare earth ions, and the physical properties of the material are dominated primarily by the B site transition metal ions. If transition metal ions can be introduced into the A site and the B site simultaneously, a multi-order ordered perovskite is formed. Chemical formula is AA'₃B₄O₁₂The compounds of (a) are such multi-order perovskite structures. Many atomic positions in such systems are occupied by transition metal ions at the same time, so in addition to the traditional B-B interaction, there are also a ' -a ' and interactions between the different atomic positions of a ' -B. The occurrence of these interactions leads to many novel interesting physical phenomena, such as large and almost constant dielectric constant in the wide temperature range, colossal magnetoresistance under the action of non-double exchange mechanisms, d-electron heavy fermi-nic behaviour, etc. As three-fourths of A sites in the perovskite structure of the structure are occupied by transition metal ions with smaller ionic radius, BO is used for stabilizing the perovskite crystal structure₆The octahedron must be highly inclined. The perovskite system with strong Jahn-Teller distortion can be prepared only under extreme conditions of high pressure, high temperature and the like.

In AA'₃B₄O₁₂In the type A site ordered perovskite, the A site is a regular icosahedron composed of twelve coordination, generally composed of alkaline earth and rare earth metal, and the A' site is a planar quadrangle composed of four coordination, generally occupied by ions with strong Jahn-Teller effect. Currently common AA'₃B₄O₁₂In the type A site ordered perovskite, the A' site is almost completely formed by Cu²⁺Or Mn³⁺And (4) occupation. In the research, a novel A-site ordered perovskite novel material PbHg is synthesized under the conditions of high temperature and high pressure₃Ti₄O₁₂The first discovery is to remove Cu²⁺And Mn³⁺In addition, Hg²⁺The ions can alsoTo occupy the A' bit; in addition, studies have shown that PbHg₃Ti₄O₁₂Has very large dielectric constant in room temperature and wide frequency range, and is a new dielectric material.

Disclosure of Invention

One of the purposes of the invention is to provide a multi-order perovskite PbHg₃Ti₄O₁₂And (4) crystals. The crystal can provide a material basis for exploring magnetoelectric, ferroelectric, piezoelectric and other physical phenomena.

Another purpose of the invention is to provide the preparation of the multi-order ordered perovskite PbHg₃Ti₄O₁₂A method for producing the crystal.

In order to achieve the above object, the present invention provides, in a first aspect, a multi-order perovskite PbHg₃Ti₄O₁₂A crystal wherein, using Cu target K α diffraction, its X-ray powder diffraction pattern expressed in 2 θ angles has diffraction peaks at 22.98, 32.72, 40.36, 46.95, 52.90 and 58.41 with 2 θ angle measurement error of ± 0.01.

Preferably, in the crystal according to the present invention, a Cu target K α diffraction is used, which has an X-ray powder diffraction pattern expressed in 2 θ angles with diffraction peaks at 68.58, 73.39, 78.08, 82.70, 87.26, 91.81 and 96.37, and a 2 θ angle measurement error of ± 0.01.

Preferably, in the crystal of the present invention, the PbHg is present₃Ti₄O₁₂The crystal is cubic system, space group is Im-3(NO.204), and lattice constantThe coordinates of each atom in the unit cell are Pb (0,0,0), Hg (0,0.5,0.5), Ti (0.25,0.25,0.25), O (0,0.7028, 0.2176).

In a second aspect, the present invention provides a method for preparing the multi-order perovskite PbHg of the present invention₃Ti₄O₁₂A method of crystallizing comprising the steps of:

(1) mixing PbO₂HgO and TiO₂Fully grinding according to the molar ratio of 1:3: 4;

(2) sealing and wrapping the powder obtained in the step (1)Then sintering is carried out to obtain the multi-order perovskite PbHg₃Ti₄O₁₂And (4) crystals.

Preferably, in the method of the present invention, the sealing wrap in the step (2) is performed by a method comprising the steps of: pressing the powder obtained in the step (1) into a cylindrical sample, and hermetically wrapping the cylindrical sample by using a gold foil.

Preferably, in the method of the present invention, the step (2) further comprises the step of polishing the sintered sample on a sand paper to remove the gold foil on the surface of the sample.

Preferably, in the method of the present invention, the sintering temperature in step (2) is 500-1400 ℃, and the sintering pressure is 2-8 GPa.

Preferably, in the method of the present invention, the sintering in the step (2) is performed for 0.1 to 6 hours.

The invention has the following beneficial effects:

the multi-order ordered perovskite PbHg of the invention₃Ti₄O₁₂The crystal belongs to a cubic crystal system Im-3(NO.204) space group, provides a good material basis for researching physical phenomena such as magnetoelectricity evolution and the like, is a potential quantum functional material, and has important physical significance for researching a strong correlation system.

Drawings

Embodiments of the invention are described in detail below with reference to the attached drawing figures, wherein:

FIG. 1 is PbHg of example 1 of the present invention₃Ti₄O₁₂A schematic of the structure of the crystal;

FIG. 2 is PbHg of example 1 of the present invention₃Ti₄O₁₂Transmission electron micrograph of crystal

FIG. 3 is PbHg of example 1 of the present invention₃Ti₄O₁₂An X-ray diffraction pattern of the crystal;

FIG. 4 is PbHg of example 1 of the present invention₃Ti₄O₁₂Neutron diffraction patterns of the crystals;

FIG. 5 is PbHg of example 1 of the present invention₃Ti₄O₁₂Dielectric constant versus frequency curve at room temperature.

Detailed Description

The present invention is described in further detail below with reference to specific embodiments, which are given for the purpose of illustration only and are not intended to limit the scope of the invention.