세차전자회절을 이용한 BaTiO3 나노 결정의 구조분석
Structure Determination of Nano-crystalline, BaTiO3, using Precession Electron Diffraction
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The crystal structure of nano-crystalline, BaTiO3, with the average particle size of 100 nm was investigated using electrondiffraction techniques. We characterized the precession electron diffraction system and then carried out the 본 연구에서는 평균 입자크기가 100 nm인 BaTiO3 나노 결정체의 결정 구조를 전자회절을 이용하여 분석하였다. 전자회절을이용하여 구조분석을 수행하기 위해 PED 장치의 실험인자를 보정한 후, PED와 일반적인 SAED를 이용하여 전자회절도형을 획득하여 비교 분석을 수행하였다. BaTiO3 나노 결정체에 대해PED를 이용한 구조분석을 수행한 결과, BaTiO3 나노입자는 상온에서 입방정계와 정방정계의 구조가 혼합되어 존재함을 알 수있었다. 또한 이론적 계산을 통해 두 상이 혼재된 BaTiO3 나노입자는 입방정계의 구조가 약 8.5nm의 표면을 형성하고 있는 coreshell구조를 이루고 있음을 예측할 수 있었다. 이러한 BaTiO3 나노입자에 대한 입방정계와 정방정계 구조의 각각의 격자상수는a=3.999 Å과 a=3.999 Å, c=4.022 Å이었다. 이와 같이 일반적인SAED에 비해 뛰어난 공간분해능과 다중산란 효과를 억제할 수있는 PED 기법은 복합 나노 구조체의 결정구조분석에 보다 유용한 분석 기술로 활용할 수 있을 것으로 기대된다.
Abstract
The crystal structure of nano-crystalline, BaTiO3, with the average particle size of 100 nm was investigated using electrondiffraction techniques. We characterized the precession electron diffraction system and then carried out the structuredetermination using precession electron diffraction and conventional selected area electron diffraction. As a result, it wasrevealed that BaTiO3 nano-crystalline exist as a mixture of tetragonal structure and cubic structure by precession electrondiffraction technique. In addition, it could be turned out that BaTiO3 nano-crystalline is a core-shell structure consisted ofa tetragonal phased core and a cubic phased surface layer by theoretical calculation. The thickness of the cubic surfacelayer was approximately 8.5 nm and the lattice parameters of cubic and tetragonal phases were a=3.999 Å and a=3.999Å, c=4.022 Å, respectively. Finally, it is expected that precession electron diffraction is more useful technique for structuredetermination of complicated nano-crystalline materials because of its higher spatial resolution and minimization ofdynamical scattering effect.
참고문헌 (17)
- Aoyagi S, "Size effect on crystal structure and chemical bonding nature in BaTiO3 nanopowder", J Therm Anal Calorim, 81, pp.627~630 (2005)
- Arlt G, "Dielectric properties of fine-grained barium titanate ceramics", J Appl Phys, 58, pp.1619~ (1985)
- Avilov A, "Precession technique and ED as new tools for crystal structure analysis and chemical bonding determination", Ultramicroscopy, 107, pp.431~444 (2007)
- Begg BD, "Particle size effect on the room temperature structure of barium titanate", J Am Ceram Soc, 77, pp.3186~ (1994)
- Forsbergh PW Jr, "Domain structures and phase transitions in barium titanate", Phys Rev, 76, pp.1187~1201 (1949)
- Huang WJ, "Towards sub-Å atomic resolution electron diffraction imaging of metallic nanoclusters: A simualtion study of experimental parameters and reconstruction algorithms", Ultramicroscopy, 107, pp.1159~1170 (2007)
- Kim YI, "Structural study of nano BaTiO3 powder by rietveld refinement", Mater Res Bull, 39, pp.1045~1053 (2004)
- Knoshita K, "Grain-size effects on dielectric properties in barium titanate", J Appl Phys, 47, pp.371~373 (1976)
- S.-M. Moon, "Size Effects on the Crystal Structure of Nanoscale BaTiO3 Powders Prepared by Hydro-Thermal Synthesis", Metals and Materials International, 13(4), pp.329~333 (2007), 대한금속·재료학회
- Shirane G, "Neutron diffraction study of orthorhombic BaTiO3", Phys Rev, 105, pp.856~860 (1957)
- Takeuchi T, "Thickness of cubic surface phase on barium titanate single-crystalline grains", J Am Ceram Soc, 77, pp.1665~1668 (1994)
- Uchino K, "Dependence of the crystal structure on particle size in barium titanate", J Am Ceram Soc, 72, pp.1555~1558 (1989)
- Vincent R, "Double conical beam-rocking system for measurement of integrated electron diffraction intensities", Ultramicroscopy, 53, pp.271~282 (1994)
- Vincent R, "Measurement of kinematic intensities from large-angle electron-diffraction patterns", Philos Mag Lett, 53, pp.L35~L40 (1986)
- Wada S, "Preparation of nm-sized BaTiO3 particles using a new 2-step thermal decomposition of barium titanyl oxalate", J Mater Sci, 38, pp.2655~2660 (2003)
- Wada S, "Preparation of nm-sized barium titanate fine particles and their powder dielectric properties", Jpn J Appl Phys Part 1, 42, pp.6188~6195 (2003)
- Zou XD, "ELD-a computer program system for extracting intensities from electron diffraction patterns", Ultramicroscopy, 49, pp.147~158 (1993)