High-resolution electron microscopy (HREM) examination of dislocation core structure in B2 FeAl single crystals

The geometric phase technique (GPA) for measuring the distortion of crystalline lattices from high-resolution electron microscopy (HRTEM) images will be described. The method is based on the calculation of the “local” Fourier components of the HRTEM image by filtering in Fourier space. The method will be illustrated with a study of an edge dislocation in silicon where displacements have been measured to an accuracy of 3 pm at nanometre resolution as compared with anisotropic elastic theory calculations. The different components of the strain tensor will be mapped out in the vicinity of the dislocation core and compared with theory. The accuracy is of the order of 0.5% for strain and 0.1° for rigid-body rotations. Using bulk elastic constants for silicon, the stress field is determined to 0.5 GPa at nanometre spatial resolution. Accuracy and the spatial resolution of the technique will be discussed.

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MgO single crystals as specimen supports for high resolution electron microscopy

Ultramicroscopy ◽

10.1016/0304-3991(82)90093-6 ◽

1982 ◽

Vol 9 (4) ◽

pp. 325-335 ◽

Cited By ~ 3

Author(s):

Y. Uchida ◽

G. Lehmpfuhl ◽

K. Weiss ◽

F. Zemlin

Keyword(s):

Electron Microscopy ◽

High Resolution ◽

Single Crystals ◽

High Resolution Electron Microscopy ◽

Resolution Electron

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Dislocation core studies using high resolution electron microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100108052 ◽

1978 ◽

Vol 36 (1) ◽

pp. 182-183

Author(s):

D.J.H. Cockayne ◽

G.R. Anstis

Keyword(s):

Electron Microscopy ◽

High Resolution ◽

Unique Solution ◽

Lattice Distortion ◽

Image Interpretation ◽

Dislocation Core ◽

High Resolution Electron Microscopy ◽

Resolution Electron ◽

Image Position ◽

Image Detail

The interpretation of high resolution (0.5nm) image detail to study dislocation cores relies upon image calculations for its justification. The scattering equations used to calculate these images make use of various approximations, and their validity at this level of resolution has been in doubt. Because of this, a detailed study has been made of the various methods of image calculation, and the reliability of image interpretation for a number of experimental situations has been determined.Images of dislocations of arbitrary resolution can be calculated by an extension of the approach considered by Howie and Basinski. Given an expansion of the potential V(r) = Σgvg(r) exp (2Πig.r) and wavefunctionsthen, for a given incident wavefunction, the wavefunction ψ(r) = Σgϕg(r) exp (2Πig.r) is the unique solution to the form of Schroedinger's equation in which backscattering is neglected, irrespective of the extent of lattice distortion.

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Ordered Structures in Gd2CuO4 and isostructural cuprates

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010015277x ◽

1989 ◽

Vol 47 ◽

pp. 160-161

Author(s):

T. E. Mitchell ◽

T. Roy ◽

Z. Fisk ◽

S-W Cheong ◽

J. D. Thompson ◽

...

Keyword(s):

Electron Microscopy ◽

High Resolution ◽

Single Crystals ◽

Liquid Nitrogen ◽

High Resolution Electron Microscopy ◽

Ion Milling ◽

Ordered Structures ◽

Resolution Electron

INTRODUCTION.The lanthanide cuprates Ln2CuO4 (Ln = Pr, Nd, Eu, Gd, etc.), have a a triple perovskite unit cell.The structure is tetragonal, 14/mmm, a ∼ 0.39nm, c ∼1.19nm, with layered nets of [CuO4] squares. By contrast, the structure of La2CuO4, which also has a triple perovskite cell, contains layers of [CuO6] octahedra. La2CuO4 becomes superconducting by doping with SrO while Ln2CuO4 becomes superconducting by doping with CeO2 for Ln = Pr, Nd and Sm. Both La2CuO4 and YBa2Cu3O7 have a tetragonal-to-orthorhombic transformation while Ln2CuO4 remains tetragonal.The present study was undertaken to investigate microstructures in the lanthanide cuprates.EXPERIMENTAL. The Ln2CuO4 single crystals were grown as plates from a PbO or CuO flux. Specimens for TEM were prepared by ion milling using a liquid nitrogen specimen cooler. High resolution electron microscopy (HREM) was performed on either a Philips CM3OST at 300kV or a JEM4000FX at 400kV.

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Structural Studies of Metal-Semiconductor Interfaces with High-Resolution Electron Microscopy

MRS Proceedings ◽

10.1557/proc-14-395 ◽

1982 ◽

Vol 14 ◽

Cited By ~ 23

Author(s):

J. M. Gibson ◽

R. T. Tung ◽

J. M. Poate

Keyword(s):

Electron Microscopy ◽

High Resolution ◽

Dislocation Core ◽

High Resolution Electron Microscopy ◽

Nucleation And Growth ◽

Interfacial Structure ◽

Preparation Conditions ◽

Semiconductor Interfaces ◽

Resolution Electron ◽

Crystal Films

ABSTRACTWe have studied interface atomic structure in epitaxial cobalt and nickel disilicides on silicon using high-resolution transmission electron microscopy. By employing UHV techniques during deposition and reaction we have grown truly single-crystalline NiSi2 and CoSi2 films on (111) Si and in the former case on (100) Si. These films are shown to be continuous to below 10Å thickness. By close control over preparation conditions, afforded by UHV, we can greatly influence the nucleation and growth of these films to the extent, for example with NiSi2 on (111)Si, of yielding continuous single-crystal films with either of two orientations as desired. Whilst in the (111) NiSi2 on Si system the interfacial structure invariably appears to well-fit a model in which metal atoms nearest to the interface are 7-fold co-ordinated, for (111) CoSi2 on Si agreement is generally better with a model involving 5-fold co-ordination of these atoms. A misfit dislocation core is also imaged. Results are discussed in the light of silicide nucleation and growth. The structure and stability of the (100) NiSi2 on Si interface is also considered.

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