Phase Transition inall-trans-β-Carotene Crystal: Temperature-Dependent Raman Spectra

2015 ◽  
Vol 119 (38) ◽  
pp. 9778-9784 ◽  
Author(s):  
Kleber J. R. da Silva ◽  
Waldomiro Paschoal Jr. ◽  
Ezequiel A. Belo ◽  
Sanclayton G. C. Moreira
Keyword(s):  
Phase Transition ◽  
Raman Spectra ◽  
Crystal Temperature ◽  
Temperature Dependent ◽  
Β Carotene

Nanodomain Size Distribution in Relaxor Ferroelectrics Determined from Temperature Dependent Raman Scattering

2006 ◽  
Vol 966 ◽  
Author(s):  
Sanju Gupta
Keyword(s):  
Phase Transition ◽  
Solid Solution ◽  
Raman Spectroscopy ◽  
Raman Scattering ◽  
Size Distribution ◽  
Raman Spectra ◽  
Structural Phase ◽  
Relaxor Ferroelectrics ◽  
Temperature Dependent ◽  
Polarization Mechanism

ABSTRACTRelaxors (PZN, in particular) is an important class of self-assembled nanostructure composite ferroelectric oxides (or perovskite) materials. The interesting features associated with the nanoregions/nanodomains required to describe these relaxors give rise to the most relevant device related characteristics and peculiar physical properties in these materials. In addition, they possess astronomical property coefficients by themselves or when modified with lead titanate (PT) forming solid solution. In the past, we conducted temperature dependent Raman scattering studies on solid solution (1−x)PZN−xPT relaxors single crystals with varying composition; x = 0.02, 0.085, and 0.11. These studies were performed to obtain relevant information about lattice/phonon dynamics for matching the application criteria such as electromechanical actuators. We showed that the sharp structural phase transition occurs at or near 460 K which is a first-order transition by fitting two spectroscopic variables in Raman spectra for one of the representative bands occurring at 277 cm−1. Besides structural phase transition, polarization mechanism for the unpoled (x = 0.02) and poled (x = 0.05) specimens is also investigated to understand the polarization mechanism in relaxors using Raman spectroscopy. The difference in the case of poled specimen is accounted for by the influence of residual electric field. Poling also suggested an enhanced local ordering and the increase in the volume of the polar nano-regions. In the present report, we attempted to determine the nanopolar region size and distribution using the above mentioned temperature dependent Raman spectra. We discuss the most suitable mathematical form of nanodomain size distribution for such inhomogeneous material is log-normal and it is bimodal depending upon the temperature regime in addition to composition. These studies helped to determine the size distribution of nanoscopic embodiments in relaxor ferroelectrics using Raman spectroscopy as a function of temperature which is a dynamical phenomenon.

Effect of The Phase-transition on The Ultraviolet-visible Absorption and Resonance Raman Spectra of All-trans-β-carotene

2016 ◽  
Vol 37 (4) ◽  
pp. 498-502
Author(s):  
李 硕 LI Shuo ◽  
孙成林 SUN Cheng-lin ◽  
高淑琴 GAO Shu-qin ◽  
里佐威 LI Zuo-wei ◽  
苑举辉 YUAN Ju-hui ◽  
...  
Keyword(s):  
Phase Transition ◽  
Raman Spectra ◽  
Resonance Raman ◽  
Visible Absorption ◽  
Resonance Raman Spectra ◽  
Β Carotene

Structural transition of VO2 (A) nanorods studied by vibrational spectroscopies

RSC Advances ◽  
2014 ◽  
Vol 4 (35) ◽  
pp. 18055-18060 ◽  
Author(s):  
Jiwei Hou ◽  
Jianwu Zhang ◽  
Zhongping Wang ◽  
Zengming Zhang ◽  
Zejun Ding
Keyword(s):  
Phase Transition ◽  
Raman Spectrum ◽  
Raman Spectra ◽  
Structural Transition ◽  
Temperature Dependent ◽  
Vibrational Spectroscopies ◽  
Increasing Temperature ◽  
Induce Phase ◽  
Induce Phase Transition

The temperature-induce phase transition of VO2 (A) nanorods was observed from the Raman spectrum. Temperature-dependent Raman spectra of the VO2 (A) during the increasing temperature.

scholarly journals Raman Spectra of Diphenylalanine Microtubes: Polarisation and Temperature Effects

Crystals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 224 ◽  
Author(s):  
Alexander Krylov ◽  
Svetlana Krylova ◽  
Svitlana Kopyl ◽  
Aleksandr Krylov ◽  
Ferid Salehli ◽  
...  
Keyword(s):  
Phase Transition ◽  
Physical Properties ◽  
Raman Spectra ◽  
Temperature Effects ◽  
Structural Phase ◽  
Water Molecules ◽  
Temperature Dependent ◽  
Temperature Behaviour ◽  
Anomalous Temperature ◽  
Temperature Changes

Diphenylalanine microtubes have remarkable physical properties that allow one to use them in electronics. In this work, we measured polarised temperature-dependent Raman spectra in self-assembled diphenylalanine microtubes grown from the solution. We observed the anomalous temperature behaviour of the Raman lines. Their temperature changes were minimal, which required a significant improvement in the resolution and stability of Raman measurements. The anomalies in the behaviour of the spectra at about 178 K, 235 K, 255 K, 278 K, 296 K, 398 K and 412 K were observed. The structural phase transition at 398 K is irreversible. This transition is associated with the release of water molecules from nanochannels. The irreversible phase transition has a temperature range of about 10 K.

Single Crystal Raman Spectra of the Phase Transition in KTCNQ

1982 ◽  
Vol 85 (1) ◽  
pp. 297-303 ◽  
Author(s):  
A. D. Bandrauk ◽  
K. D. Truong ◽  
S. Jandl
Keyword(s):  
Phase Transition ◽  
Single Crystal ◽  
Raman Spectra

Temperature-Dependent Solid-state Luminescence and Reversible Phase Transition of (n-Bu4N)[Au(SC6H3-3,5-Me2)2]

2003 ◽  
Vol 32 (11) ◽  
pp. 1002-1003 ◽  
Author(s):  
Seiji Watase ◽  
Takayuki Kitamura ◽  
Nobuko Kanehisa ◽  
Masami Nakamoto ◽  
Yasushi Kai ◽  
...  
Keyword(s):  
Phase Transition ◽  
Solid State ◽  
Temperature Dependent ◽  
Reversible Phase Transition ◽  
Reversible Phase ◽  
State Luminescence
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