Material for realizing relaxation-normal ferroelectric phase change through doping, and method thereof

A ferroelectric phase and normal technology, which is applied to materials and fields that realize relaxor-normal ferroelectric phase transition through doping, can solve complex chemical compositions, difficult relaxor-normal ferroelectric phase transition, disturbed long-range ferroelectric phase transition order and other problems, to achieve the effect of no complex process and low cost

Inactive Publication Date: 2021-11-19
NANJING UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] At present, research on phase transitions in this area is mainly concentrated in perovskite ferroelectric materials. In particular, normal-relaxation ferroelectric phase transitions are generally easy to achieve, because substitution or doping generally makes the material The chemical composition of the ferroelectric material is more complex, which will disturb the long-range ferroelectric order, suppress the size of the ferroelectric domain, thereby enhancing the relaxation degree of the ferroelectric material, resulting in a normal-relaxation ferroelectric phase transition
This also means that it is difficult to achieve the relaxation-normal ferroelectric phase transition by means of doping, so there are few reports on the relaxation-normal ferroelectric phase transition

Method used

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  • Material for realizing relaxation-normal ferroelectric phase change through doping, and method thereof
  • Material for realizing relaxation-normal ferroelectric phase change through doping, and method thereof
  • Material for realizing relaxation-normal ferroelectric phase change through doping, and method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Weighing 3.9144 grams SrCO 3 Powder, BaCO 1.7441 g 3 Powder and 9.3501 g Nb 2 O 5 Powder (x = 0), with an appropriate amount into a ball mill jar, and milling beads were added approximately 2 / 3 of ball mill pot volume of distilled water, ball milled for 24 hours to mix well. The resulting dried powder was treated with the appropriate amount of pressure 15MPa powder is pressed into a diameter of about 20 mm, the bulk thickness of about 5-6 mm. In Al 2 O 3 Crucible lid bottom with a thin layer of powder is mixed, and then molded into a good block, of Al 2 O 3 Cover discs on the crucible, causing the block to a sealed state. The crucible was placed in a muffle furnace, heat from room temperature to 400 ℃ 30 minutes and then heated to the sintering temperature (1400 deg.] C) for 3 hours after the temperature was lowered to 400 ℃, followed by furnace cooling to room temperature, ramp rate control in the entire 5 ℃ / min. After the obtained ceramic block, which is hand ground wit...

Embodiment 2

[0022] Weigh 3.2076 g SBN single phase powder, 0.1115 g Na 2 CO 3 Powder and 0.2805 g Nb 2 O 5Powder (x = 0.2), into a ball mill jar milled with an appropriate amount of beads was added and about 2 / 3 of the tank volume ethanol milling, ball milled for 24 hours to mix well. The resulting slurry is dried, the amount of pressure 15MPa powder was pressed into a diameter of about 10 mm, a sheet thickness of about 2-3 mm. In Al 2 O 3 Laying a thin layer of the bottom of the crucible component powder, and then molded into a sheet good, and the cover sheet with the powder, and finally Al 2 O 3 Wafer on the crucible cover, the sheet in a sealed state. The sheet is sealed crucible placed in a muffle furnace and heated, heat from room temperature to 400 ℃ 30 minutes and then heated to the sintering temperature (1250 deg.] C) for 3 hours after the temperature was lowered to 400 ℃, followed by furnace cooling to room temperature, the whole ramp rate control at 5 ℃ / min. Obtaining the formula ...

Embodiment 3

[0024] Single phase weighed 2.4057 g and 0.2230 g Na powder SBN 2 CO 3 Powder and 0.5610 g Nb 2 O 5 Powder (x = 0.4), into a ball mill jar milled with an appropriate amount of beads was added and about 2 / 3 of the tank volume ethanol milling, ball milled for 24 hours to mix well. The resulting slurry is dried, the amount of pressure 15MPa powder was pressed into a diameter of about 10 mm, a sheet thickness of about 2-3 mm. In Al 2 O 3 Spread a thin layer of the crucible bottom and then molded into a sheet after the good component powder, and the powder was covered with a sheet, finally Al 2 O 3 Wafer on the crucible cover, the sheet in a sealed state. The sheet is sealed crucible placed in a muffle furnace and heated, heat from room temperature to 400 ℃ 30 minutes and then heated to the sintering temperature (1200 deg.] C) for 3 hours after the temperature was lowered to 400 ℃, followed by furnace cooling to room temperature, the whole ramp rate control at 5 ℃ / min. Obtaining the ...

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Abstract

The invention discloses a material for realizing relaxation-normal ferroelectric phase change through doping, and a method thereof. The chemical formula of the material is (1-x)SBN-xNN (x = 0-0.8). Na<+> in the material occupies an A-site lattice position which is not occupied by Sr<2+> and Ba<2+> in a tungsten bronze structure, when x is equal to 0, the material is of a non-filled tungsten bronze structure, when x is equal to 0.4, the material is of a filled tungsten bronze structure, and when x is greater than 0.4, the material has a tungsten bronze and perovskite two-phase coexisting composite structure. The method comprises the following steps: synthesizing single-phase SBN powder by adopting a two-step solid-phase reaction method, uniformly mixing the single-phase SBN powder with Na2CO3 and Nb2O5 powder, and sintering at high temperature to obtain the corresponding ceramic material. By doping NN, the SBN crystal structure is converted from a non-full type to a full type, relaxation-normal ferroelectric phase change occurs when x is equal to 0.4, and relaxation-normal ferroelectric phase change which is difficult to realize under general conditions is realized.

Description

Technical field [0001] The present invention relates to a NaNbO 3 (NN) Sr doped tungsten bronze structure 0.75 BA 0.25 NB 2 O 6 (SBN), relaxation achieve - normal ferroelectric phase change material and its preparation method. Background technique [0002] Relaxor ferroelectrics generally have a small or even irregular shapes nanoscale ferroelectric domains, it appears to have an elongated macroscopic hysteresis loop, a small remanent polarization, coercive field smaller features. Ferroelectric domains and ferroelectric is normally a regular shape with a larger, macro performance is a saturated hysteresis loop, large remanent polarization, a large coercive field and so on. In theory, achieve mutual transition between relaxation and normal ferroelectrics can effectively control the size and morphology of the ferroelectric domain, which has a very important practical significance for optimizing macroscopic electrical properties. [0003] Currently, research in this regard change ma...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/495C04B35/622C04B35/626C04B35/64
CPCC04B35/495C04B35/622C04B35/62605C04B35/64C04B2235/3213C04B2235/3215C04B2235/3201C04B2235/6562C04B2235/6565C04B2235/6567C04B2235/96
Inventor 张善涛何晓娟张亦弛顾正彬
Owner NANJING UNIV
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