Method for preparing multi-ferroic material under intense magnetic field

A strong magnetic field, multiferroic technology, applied in the field of BiFeO3 preparation, can solve the problems of weak magnetoelectric coupling strength and small macroscopic magnetic moment

Inactive Publication Date: 2008-10-08
INST OF ELECTRICAL ENG CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Its shortcoming is that the macroscopic magnetic moment is small and the magnetoelectric coupling strength is weak.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Preparation of BiFeO 3 Polycrystalline samples. The precursor is prepared by ordinary sol-gel method (sol-gel), and the pure Fe(NO 3 ) 3 .9H 2 O and Bi(NO 3 ) 3 .5H 2 Each 0.01 mole of O crystal particles and 30 grams of citric acid are dissolved in deionized water to form a mixed solution. The concentrated solution is heated in a microwave oven and the water is evaporated. It takes about fifteen minutes to obtain the gel precursor Bi-Fe-O powder. The gel precursor Bi-Fe-O powder obtained above is compressed into small tablets with an ordinary small tablet press to obtain a block sample. Then put the block sample in a strong magnetic field heating furnace with oxygen atmosphere, first turn on the strong magnetic field power supply, turn on the power supply of the heating furnace after the magnetic field stabilizes, and keep it at a magnetic field strength of 20 Tesla and a temperature of 550°C for 1 hour. Then the temperature is lowered at 1°C / min to 100°C, the heat treatme...

Embodiment 2

[0020] Preparation of BiFeO 3 Film samples. The thin film is prepared by ordinary sol-gel method (sol-gel), and the pure Fe(NO 3 ) 3 .9H 2 O and Bi(NO 3 ) 3 .5H 2O crystal particles of 0.01 mol and 30 g of citric acid are dissolved in deionized water to form a mixed solution, then 5 ml of glacial acetic acid is added for dehydration, and the concentrated solution is heated in a microwave oven, using LaAlO 3 Or SrTiO 3 As the substrate, spin-coated thin film. Place the film sample in a strong magnetic field heating furnace with argon atmosphere, first turn on the strong magnetic field power supply, turn on the power supply of the furnace after the magnetic field is stable, and keep it at a magnetic field strength of 10 Tesla and a temperature of 400°C for 6 hours, then Cool down at 1°C / min to 200°C, turn off the power of the heat treatment furnace, and finally turn off the power of the magnetic field, so that the sample is naturally cooled to room temperature with the heat treatmen...

Embodiment 3

[0022] Preparation of BiFeO 3 Film samples. Preparation of BiFeO by Magnetron Sputtering Apparatus 3 film. Then put the film sample in a strong magnetic field heating furnace with an air atmosphere, first turn on the strong magnetic field power supply, turn on the power supply of the furnace after the magnetic field stabilizes, and keep it at a magnetic field strength of 20 Tesla and a temperature of 550°C for 1 hour, then Cool down at 1°C / min to 100°C, turn off the power of the heat treatment furnace, and finally turn off the power of the magnetic field, so that the sample is naturally cooled to room temperature with the heat treatment furnace to obtain BiFeO 3 Film samples.

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Abstract

The invention discloses a method for preparing and treating a multiferroics BiFeO3 in the intense magnetic field environment. The method is characterized in that a BiFeO3 sample is prepared and treated by utilizing the intense magnetic field, so as to improve the magnetoelectric coupling performance of BiFeO3. A Bi-Fe-O precursor and a thin film is prepared or the BiFeO3 sample is directly produced (including polycrystal, single crystal, nano-material or thin film) by adopting a chemical method or a physical method, then the prepared products are positioned in an intense magnetic field heating furnace in an atmosphere with air or other gases (such as oxygen) for sintering or annealing, and are cooled down to the room temperature by rapid quenching or adopting the cooling speed of 1 DEG C / min after the heat preservation for one to six hours at the magnetic field intensity of between 0 and 20-tesla and a temperature of between 400 and 880 DEG C. The method can effectively improve the macroscopic magnetic moment and saturation polarization intensity of BiFeO3 and enhance the magnetoelectric coupling effect.

Description

Technical field [0001] The invention belongs to a strong magnetic field preparation method for multiferroic materials, and particularly relates to a BiFeO 3 The preparation method. Background technique [0002] In recent years, researches on multiferroic materials for designing multifunctional devices have been extensively carried out. Among them, BiFeO3 has received the most attention because of its magnetoelectric effect higher than room temperature [SWCheong and M.Mostovoy, Nature Materials 6, 13 (2007), W. Eerenstein, NDMathur, and JFScott, Nature 442, 759 (2006) ), R. Ramesh and NASpaldin, Nature Materials 6, 21 (2007)]. Unfortunately, although BiFeO3 has a high Curie temperature, the first discovered macroscopic magnetic moment of BiFeO3 is only 0.01μB / fu [P.Fisher et al., J.Phys.C, 13, 1931 (1980)], saturated The polarization intensity is only 6μC / cm2 [JRTeague et al., SolidState Commun., 8, 1073 (1970)], which is far from the actual application requirements. In order to i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/26C04B35/622
Inventor 罗万居王军红王栋樑刘敏马衍伟
Owner INST OF ELECTRICAL ENG CHINESE ACAD OF SCI
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