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Invited Review Article: Photopyroelectric calorimeter for the simultaneous thermal, optical, and structural characterization of samples over phase transitions
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10.1063/1.3663970
/content/aip/journal/rsi/82/12/10.1063/1.3663970
http://aip.metastore.ingenta.com/content/aip/journal/rsi/82/12/10.1063/1.3663970
View: Figures

Figures

Image of FIG. 1.
FIG. 1.

Equivalent circuit for the pyroelectric transducer and the detection electronics.

Image of FIG. 2.
FIG. 2.

Layer stack sequence for the one-dimensional model of the PPE signal.

Image of FIG. 3.
FIG. 3.

Geometry of the PPE back-detection configuration (BPPE). Optical absorption takes place at the cell bottom-sample (b-s) interface.

Image of FIG. 4.
FIG. 4.

Geometry of the PPE front-detection configuration with sensor opaque front electrode (FPPE1). Optical absorption takes place at the sensor-air (p-g) interface.

Image of FIG. 5.
FIG. 5.

Geometry of the PPE front-detection configuration with sensor transparent front electrode (FPPE2). Optical absorption takes place at the sensor-sample (p-s) interface.

Image of FIG. 6.
FIG. 6.

Schematic view of the experimental setup of the integrated PPE calorimeter.

Image of FIG. 7.
FIG. 7.

PPE signal amplitude (A) and phase (Φ) vs frequency obtained for the LaTiO3 transducer alone.

Image of FIG. 8.
FIG. 8.

Experimental data (circles) and theoretical curves (continuous curves) for the ln(|V n |) and Φ n (see text) amplitude and phase for a 105 μm thick water sample in the BPPE. Other symbols and curves correspond to situations not referred to in the text. [Reprinted with permission from S. Delenclos et al., Rev. Sci. Instrum. 73, 2773 (2002). Copyright 2002, American Institute of Physiscs.]

Image of FIG. 9.
FIG. 9.

PPE signal amplitude (A) and phase (Φ) vs temperature for a 9CB LC sample over the smectic A-nematic and nematic-isotropic phase transitions.

Image of FIG. 10.
FIG. 10.

Specific heat (c), thermal diffusivity (D), and thermal conductivity (k) as a function of temperature obtained from the signal amplitude and phase reported in Fig. 9.

Image of FIG. 11.
FIG. 11.

High temperature resolution data of the specific heat over the smectic A-nematic phase transition in 9CB liquid crystal obtained by the ASC (black symbols) and by the PPE (gray symbols) techniques.

Image of FIG. 12.
FIG. 12.

Specific heat (c), thermal diffusivity (D), and thermal conductivity (k) as a function of temperature over the antiferromagnetic-paramagnetic phase transition in a Cr2O3 sample. The continuous lines represent the fit to the data to calculate the critical exponents.

Image of FIG. 13.
FIG. 13.

Specific heat (black symbols) and amplitude of the latent heat term I L (gray symbols) vs temperature over the antiferromagnetic-paramagnetic phase transition in CoO. [Reprinted with permission from A. Oleaga et al., Phys. Rev. B 80, 024426 (2009). Copyright 2009, American Physical Society.]

Image of FIG. 14.
FIG. 14.

Specific heat (c), thermal diffusivity (D), and thermal conductivity (k) as a function of temperature over the AN phase transitions in LC sample. The continuous lines represent the fit to the data to calculate the critical exponents.

Image of FIG. 15.
FIG. 15.

Thermal conductivity as a function of temperature, over the NI transition, for the homeotropic (gray symbols) and the planar (black symbols) samples of 5CB LC.

Image of FIG. 16.
FIG. 16.

Orientational order parameter as a function of temperature, over the NI transition, obtained from the anisotropy of the thermal conductivity for a sample of 5CB LC. Squares and triangles represent data obtained by other techniques (see text). [Reprinted with permission from M. Marinelli et al., Phys. Rev. E 58, 5860 (1998). Copyright 1998, American Physical Society.]

Image of FIG. 17.
FIG. 17.

Thermal conductivity of an initially planar single domain sample of 8CB LC as function of the applied voltage, obtained T = TNI – 0.015 °C, showing the Fréedericksz transition (see text) occurring at V th .

Image of FIG. 18.
FIG. 18.

Thermal conductivity for single domain homeotropic and planar samples of pure 8CB with various concentrations of silica nanoparticles.

Image of FIG. 19.
FIG. 19.

PPE signal phase behaviour over the AC transition of the racemic A7 LC compound during the sample cooling (black sysmbols) and subsequent heating (gray symbols) measurements. [Reprinted with permission from R. Mercuri et al., Phys. Rev. E 68, 051705 (2003). Copyright 2003, American Physical Society.]

Image of FIG. 20.
FIG. 20.

Textures observed in the different phases for the racemic A7 LC compound during the sample cooling [(a) SmA, (b) SmC, and (c) CrG] and during subsequent heating [(d) SmC and (e) SmA]. [Reprinted with permission from F. Mercuri et al., Phys. Rev. E 68, 051705 (2003). Copyright 2003, American Physical Society.]

Image of FIG. 21.
FIG. 21.

Specific heat (c), latent heat (I L ), and nematic correlation length (ξ) when cooling an 8CB LC sample with 2% mass ratio of silica nanoparticles over the nematic-isotropic transition. [Reprinted with permission from S. Paoloni et al., Phys. Rev. E 78, 042701 (2008). Copyright 2008, American Physical Society.]

Image of FIG. 22.
FIG. 22.

Images of the sample's texture, obtained over the HTP (a) and LTP (b) (see text) temperature regions shown in Fig. 21 when cooling an 8CB LC sample with 2% mass ratio of silica nanoparticles over the nematic-isotropic transition.

Image of FIG. 23.
FIG. 23.

Excess heat capacity over the smectic A-nematic phase transitions for mixtures with different relative ratios (x) of 5CB and D55 LC compounds near the tricritical point occurring at x ∼ 0.47. [Reprinted with permission from J. Caerels et al., Phys. Rev. E 65, 031704 (2002). Copyright 2002, American Physical Society.]

Image of FIG. 24.
FIG. 24.

Schematic diagram of the PPE measuring cell for binary mixture (a) window, (b) air, (c) upper sensor, (d) lower sensor, (e) denser sample phase, (f) lighter sample phase, (g) backing material, (h) air, and sample vapour, (i) flexible teflon membrane, (j) connecting tube, and (k) incident radiation. [Reprinted with permission from S. Pittois et al., J. Chem. Phys. 121, 1866 (2004). Copyright 2004, American Institute of Physics.]

Image of FIG. 25.
FIG. 25.

The thermal conductivity as a function of temperature of n-butoxyethanol–water mixture at the critical concentration. [Reprinted with permission from S. Pittois et al., J. Chem. Phys. 121, 1866 (2004). Copyright 2004, American Institute of Physics.]. The black diamonds and the solid line represent experimental and theoretical profile obtained by other authors.104

Image of FIG. 26.
FIG. 26.

The specific heat as a function of temperature of n-butoxyethanol–water mixture, at the critical concentration obtained by PPE and by ASC calorimetry. [Reprinted with permission from S. Pittois et al., J. Chem. Phys. 121, 1866 (2004). Copyright 2004, American Institute of Physics.]

Image of FIG. 27.
FIG. 27.

Frequency dependence of the real (top) and imaginary (bottom) parts of the square of the thermal effusivity of glycerol at different temperatures. The temperatures are varying, from left to right, from 198 to 238 K in steps of 5 K. The lines are the best Havriliak–Negami fits. [Reprinted with permission from E. H. Bentefour et al., J. Chem. Phys. 120, 3726 (2004). Copyright 2004, American Institute of Physics.]

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2011-12-23
2014-04-19
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752b84549af89a08dbdd7fdb8b9568b5 journal.articlezxybnytfddd
Scitation: Invited Review Article: Photopyroelectric calorimeter for the simultaneous thermal, optical, and structural characterization of samples over phase transitions
http://aip.metastore.ingenta.com/content/aip/journal/rsi/82/12/10.1063/1.3663970
10.1063/1.3663970
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