Phase Transitions in Frustrated ErBaCo4O7 + x (x = 0–0.06) Cobaltites at a Small Deviation from Stoichiometry

The infrared (IR) reflectivity of laser synthesized TiO2 nanopowder in the anatase phase with a small deviation from stoichiometry is reported. The samples were characterized by SEM, XRD and BET measurements as well as Raman and photoluminescence spectroscopy. Analysis of the far IR reflectivity spectrum of the nanopowder reveals a presence of a plasmon mode. The charge carriers resulting from the lattice defects, mainly oxygen vacancies, are responsible for this mode. The dielectric function in a factorized form with a plasmon contribution is used to model the IR reflectivity spectrum and a good agreement between theoretical and experimental results has been found.

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Thermodynamic analysis on point defects of UO2+x at relatively small deviation from stoichiometry between 600 and 1400°C

Journal of Nuclear Materials ◽

10.1016/0022-3115(86)90239-4 ◽

1986 ◽

Vol 140 (2) ◽

pp. 113-130 ◽

Cited By ~ 14

Author(s):

Akio Nakamura ◽

Takeo Fujino

Keyword(s):

Thermodynamic Analysis ◽

Point Defects ◽

Small Deviation ◽

Deviation From Stoichiometry

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Electron Microscopy of Graphite Intercalation Compounds

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100055564 ◽

1982 ◽

Vol 40 ◽

pp. 544-545

Author(s):

G. Timp ◽

L. Salamanca-Riba ◽

L.W. Hobbs ◽

G. Dresselhaus ◽

M.S. Dresselhaus

Keyword(s):

Electron Microscopy ◽

Phase Transitions ◽

Domain Wall ◽

Intercalation Compounds ◽

Lattice Plane ◽

Wall Model ◽

Graphite Intercalation Compounds ◽

Fundamental Symmetry ◽

Graphite Intercalation

Electron microscopy can be used to study structures and phase transitions occurring in graphite intercalations compounds. The fundamental symmetry in graphite intercalation compounds is the staging periodicity whereby each intercalate layer is separated by n graphite layers, n denoting the stage index. The currently accepted model for intercalation proposed by Herold and Daumas assumes that the sample contains equal amounts of intercalant between any two graphite layers and staged regions are confined to domains. Specifically, in a stage 2 compound, the Herold-Daumas domain wall model predicts a pleated lattice plane structure.

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Multiple phase transitions investigated by high-speed TEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100175880 ◽

1990 ◽

Vol 48 (4) ◽

pp. 550-551

Author(s):

Oleg Bostanjoglo ◽

Peter Thomsen-Schmidt

Keyword(s):

Phase Transitions ◽

High Speed ◽

Short Exposure ◽

Semiconductor Film ◽

Time Resolved ◽

Short Exposure Time ◽

Multiple Phase ◽

Model Substance ◽

History Of ◽

Electron Image

Thin GexTe1-x (x = 0.15-0.8) were studied as a model substance of a composite semiconductor film, in addition being of interest for optical storage material. Two complementary modes of time-resolved TEM were used to trace the phase transitions, induced by an attached Q-switched (50 ns FWHM) and frequency doubled (532 nm) Nd:YAG laser. The laser radiation was focused onto the specimen within the TEM to a 20 μm spot (FWHM). Discrete intermediate states were visualized by short-exposure time doubleframe imaging /1,2/. The full history of a transformation was gained by tracking the electron image intensity with photomultiplier and storage oscilloscopes (space/time resolution 100 nm/3 ns) /3/. In order to avoid radiation damage by the probing electron beam to detector and specimen, the beam is pulsed in this continuous mode of time-resolved TEM,too.Short events ( <2 μs) are followed by illuminating with an extended single electron pulse (fig. 1c)

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