Crystal structure analysis of Ca4YFe5O13by combining 1 MeV high-resolution electron microscopy with convergent-beam electron diffraction

ABSTRACTThe metamict transformation under electron irradiation has been studied in α-quartz using transmission electron microscopy (TEM) and convergent-beam electron diffraction (CBD). The transformation occurs in two stages: heterogeneous nucleation of discrete disordered inclusions and a slower homogeneous loss of crystalline order in the surrounding matrix. Both features are attributable to solidstate radiolysis, a mechanism for which is proposed. Ultrahigh resolution TEM structure images and information from zeroth and high order Laue zones in CBD confirm that shortrange correlations are the first to be lost and that longerrange correlations persist well into the metamict transformation. A transformation model is advanced in which progressive disorder evolves from small displacements of individual [SiO4] coordination units, made possible by lowered connectivity, within a framework of long-range ordered material.

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Microstructure of High Temperature Superconductors of the Perovskite Type

Australian Journal of Physics ◽

10.1071/ph870547 ◽

1987 ◽

Vol 40 (4) ◽

pp. 547 ◽

Cited By ~ 4

Author(s):

AF Moodie ◽

HJ Whitfield

Keyword(s):

Electron Microscopy ◽

High Temperature ◽

High Temperature Superconductor ◽

High Temperature Superconductors ◽

High Resolution Electron Microscopy ◽

Convergent Beam Electron Diffraction ◽

Beam Electron ◽

Resolution Electron ◽

Convergent Beam ◽

Perovskite Type

Combined high resolution electron microscopy and convergent beam electron diffraction (CBED) of the same areas of crystals of Ba3La3Cu6014 reveals defects of various types including ordinary dislocations and polytypic intergrowths. This latter type is considered to be intimately associated with the performance of this material as a high temperature superconductor ..

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Orientation Relationship between Fe2M and Martensite in M50NiL Steel

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.456.533 ◽

2013 ◽

Vol 456 ◽

pp. 533-536

Author(s):

Yan Zhi Lou

Keyword(s):

Crystal Structure ◽

Electron Microscopy ◽

High Resolution ◽

Electron Diffraction ◽

Orientation Relationship ◽

High Resolution Electron Microscopy ◽

Lattice Parameters ◽

Selected Area Electron Diffraction ◽

Resolution Electron ◽

Martensite Matrix

In this paper, high resolution electron microscopy (HREM) was used to observe nanosized Fe2M precipitates in M50NiL steel, and crystal structure of which was also investigated by selected area electron diffraction (SAED). At the same time, the orientation relationship between the Fe2M and the martensite matrix was also studied. The results suggested that crystal structure of Fe2M is close-packed hexagonal, and lattice parameters about a=b=0.473nm, c=0.772nm, α=β=90°, γ=120°. The orientation relationship between the nanoprecipitates Fe2M and martensite is and .

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