Second-phase assisted formation of {111} twins in barium titanate

Lee, Byoung-Ki; Kang, Suk–Joong L.

doi:10.1016/s1359-6454(01)00038-6

Cited by 58 publications

(64 citation statements)

References 23 publications

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“…This locally disturbed growth may be related to the incorporation of the Ti excess in the grain boundaries and perhaps to the so-called irregular grain growth observed for Ti-rich BaTiO 3 ceramics. [32][33][34] …”

Section: Stoichiometry 1: Dependence On the Group-ii/ti Ratiomentioning

confidence: 99%

Metal-organic chemical-vapor deposition of (Ba,Sr)TiO3: Nucleation and growth on Pt-(111)

Regnery

Ding

Ehrhart

et al. 2005

Journal of Applied Physics

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Thin films of the ͑Ba x Sr 1−x ͒TiO 3 ͑BST͒ solid solution series were grown by metal-organic chemical-vapor deposition ͑MOCVD͒ on platinized silicon wafers with emphasis to ͑Ba 0.7 Sr 0.3 ͒TiO 3 and SrTiO 3 . The nucleation behavior and the size of the stable nuclei were investigated by different scanning probe microscope techniques including local conductivity scanning. The characteristic differences were observed for different deposition temperatures, i.e., a homogeneous nucleation of small BST grains on the larger Pt grains at 565°C and a dominating grain-boundary nucleation at 655°C. X-ray photoelectron spectroscopy indicates a stoichiometric composition from the beginning. The microstructural evolution was investigated by high-resolution transmission electron microscopy and revealed randomly oriented grains ͑typical in-plane size 10-20 nm͒ with a high density of twins at 565°C and ͑100͒-oriented defect-free grains of slightly increased size at 655°C. This remarkably stable ͑100͒ texture seems specific for MOCVD as it is not observed for other deposition methods. The grain structure and surface morphology and their dependence on film stoichiometry ͑group-II/Ti ratio͒ are investigated. The relation between the structural and the electrical properties, capacitance, and leakage current, is finally discussed.

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Section: Stoichiometry 1: Dependence On the Group-ii/ti Ratiomentioning

confidence: 99%

Metal-organic chemical-vapor deposition of (Ba,Sr)TiO3: Nucleation and growth on Pt-(111)

Regnery

Ding

Ehrhart

et al. 2005

Journal of Applied Physics

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“…TiO 2 leaves the BaTiO 3 lattice and segregates at the grain boundaries. Excess TiO 2 is known to promote abnormal grain growth in BaTiO 3 temperatures ≤1250 • C. 12,13 In the sample with 0.1 mol% Al 2 O 3 , the Al 2 O 3 is completely incorporated into the BaTiO 3 lattice. This causes segregation of TiO 2 at the grain boundaries and promotes abnormal grain growth.…”

Section: Discussionmentioning

confidence: 99%

Effect of Al2O3 dopant on abnormal grain growth in BaTiO3

Fisher¹,

Lee²,

Brancquart³

et al. 2005

Journal of the European Ceramic Society

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“…In contrast, Kang's group investigated the details for the AGG from the viewpoint of grain boundary structure transition. 37), 38) They reported that the AGG is very sensitive to oxygen partial pressure during sintering. Even if {111} twins are included in grains, the grains never exhibit AGG in oxidizing atmosphere.…”

Section: Control Of Grain Growth Behavior In Batiomentioning

confidence: 99%

Nano/sub-nano analysis based on high resolution transmission electron microscopy for ceramic materials

Yamamoto

2011

J. Ceram. Soc. Japan

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Grain boundaries, interfaces and surfaces are very attractive areas from the viewpoint of lattice discontinuity. Doped elements and point defects often segregate there, which largely changes bulk properties such as microstructure, mechanical strength, electrical conductivity. To understand the details of the dopant effects, it is necessary to use nano-scale analysis techniques based on transmission electron microscopy with energy dispersive X-ray spectroscopy and electron energy-loss spectroscopy with nano/sub-nano electron probe. This review contains some nano-scale analysis studies performed in our research group for the grain size control of BaTiO 3 polycrystals, electrical properties across single grain boundaries of n-type BaTiO 3 , SrTiO 3 and ZnO, interface structural change of WCCo based cemented carbides and the preparation of novel dislocation nano-wires.Grain boundaries in BaTiO 3 sinters were revealed to exhibit grain boundary faceting by doping a very small amount of excess TiO 2 . The formation of the facets due to extra TiO 2 bonding is closely related to abnormal grain growth, which is often observed in TiO 2 -excess BaTiO 3 sinters. A similar faceting feature is also observed in VC-doped WCCo cemented carbides. Doped VC strongly segregates to WC/Co interfaces to form micro facets. The formation of the micro facets resulted in WC grain size reduction. In ZnO boundaries, doped Pr was revealed to segregate at the grain boundary. The segregated Pr ions are situated in specific atomic columns. Further, electron energy-loss spectroscopy has revealed that the valence of the segregated Pr ions is 3+, which means that they are not acceptors but donors to ZnO. The improvement of varistic effect observed in Pr-doped ZnO is closely related to Zn vacancies enhanced by Pr doping. Meanwhile, dislocations are a kind of one-dimensional lattice defect including extra half planes. By pipe-diffusion of dopants at dislocation cores, we can successfully develop conducting nano-wires in insulating sapphire crystals.

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Second-phase assisted formation of {111} twins in barium titanate

Cited by 58 publications

References 23 publications

Metal-organic chemical-vapor deposition of (Ba,Sr)TiO3: Nucleation and growth on Pt-(111)

Metal-organic chemical-vapor deposition of (Ba,Sr)TiO3: Nucleation and growth on Pt-(111)

Effect of Al2O3 dopant on abnormal grain growth in BaTiO3

Nano/sub-nano analysis based on high resolution transmission electron microscopy for ceramic materials

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