High-Resolution Cryogenic-Electron Microscopy Reveals Details of a Hexagonal-to-Bicontinuous Cubic Phase Transition in Mesoporous Silica Synthesis

We present evidence for a non-diffracting structural intermediate during the lamellar to inverse bicontinuous cubic phase transition and show that elastic energy drives the cubic phase to equilibrium.

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Kinetics and Mechanism of the Lamellar to Gyroid Inverse Bicontinuous Cubic Phase Transition

Langmuir ◽

10.1021/la0259555 ◽

2002 ◽

Vol 18 (20) ◽

pp. 7384-7392 ◽

Cited By ~ 48

Author(s):

Adam M. Squires ◽

R. H. Templer ◽

J. M. Seddon ◽

J. Woenckhaus ◽

R. Winter ◽

...

Keyword(s):

Phase Transition ◽

Kinetics And Mechanism ◽

Cubic Phase ◽

Bicontinuous Cubic

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Electron microscopy of the commensurate-incommensurate phase transition with the discommensuration network in 1T-TaS2

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100173972 ◽

1990 ◽

Vol 48 (4) ◽

pp. 168-169

Author(s):

Takashi Ishiguro ◽

Hiroshi Sato

Keyword(s):

Electron Microscopy ◽

Phase Transition ◽

Transmission Electron Microscopy ◽

Phase Transitions ◽

High Resolution ◽

Low Temperature ◽

Transmission Electron ◽

Continuous Rotation ◽

T Phase ◽

New Phase

Phase transitions of lT-TaS2 both on cooling from the incommensurate (IC) phase and on heating from the commensurate (C) phase are investigated by high resolution (HR) transmission electron microscopy because phase transitions are strongly hysteretic. The phases which had been identified were Normal(T>543K,no modurated wave, the Cdl2 type of structure, ao=0.336nm co=0.590nm), IC(354K< T< 543K), NC(non-commensurate or nearly commensurate, 185K<T<353K) and C(T<K). On heating from the C phase, the new phase called the T phase (nearly commensurate triclinic ) appears between 200K and 280K, and that has the discommensuration (DC) network. The HR observations at low temperature reveal both the three dimentional structure of the C phase and the DC network structure of the T phase.On cooling from the IC phase, the structure of the NC phase is essentially incommensurate in the basal plane and a continuous rotation of the moduration direction towards the C phase occurs.

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HREM study of ferroelectric domain wall in barium titanate

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100170566 ◽

1994 ◽

Vol 52 ◽

pp. 566-567

Author(s):

Laurent. Normand ◽

Alain. Thorel ◽

Yvan. Montardi

Keyword(s):

Electron Microscopy ◽

Phase Transition ◽

Transmission Electron Microscopy ◽

High Resolution ◽

Barium Titanate ◽

Domain Walls ◽

Ferroelectric Phase ◽

Ferroelectric Domain ◽

Transmission Electron ◽

The One

This study focuses on High Resolution Transmission Electron Microscopy of barium titanate in its tetragonal ferroelectric phase, and especially on the structure of domain walls. This phase is stable between about 0 °C and 130 °C. During cooling, at 130 °C barium titanate changes from a cubic parraelectric phase to a tetragonal ferroelectric phase. In this phase the spontaneous polarisation is along one of the six [001] pseudo-cubic directions. Two types of domains can be formed during the phase transition :90° and 180° domains. In 90° domains the polarisation is at 90° from the polarisation of the next domain (exactly 2* ArcTan(a/c) if a and c are the lattice parameters). For these domains the domain walls are <110< type planes ; In 180° domains the polarisation is at 180° from the one in the next domain. 180° domain walls are <100< type plane and are assumed to be purely ferroelectric.

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