X-ray Diffraction Topography of BaTiO3at Phase Transition Temperature

2009 ◽  
Vol 48 (9) ◽  
pp. 09KF01 ◽  
Author(s):  
Yasuhiro Yoneda ◽  
Yoshiki Kohmura ◽  
Yoshio Suzuki
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Phase Transition Temperature ◽  
X Ray Diffraction ◽  
X Ray

W-Doped VO2 (M) with Tunable Phase Transition Temperature

2013 ◽  
Vol 320 ◽  
pp. 483-487 ◽  
Author(s):  
Ming Li ◽  
Deng Bing Li ◽  
Jing Pan ◽  
Guang Hai Li
Keyword(s):  
Electron Microscopy ◽  
Phase Transition ◽  
Transition Temperature ◽  
Phase Transition Temperature ◽  
Variable Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Infrared Transmittance ◽  
Transmission Electron ◽  
Potential Applications

W-doped VO2 (B) nanoneedles were successfully synthesized by solgel combing with hydrothermal treatment, in which the polyethylene glycol (PEG) was used as both surfactant and reducing. The metastable VO2 (B) was completely transformed to thermochromic VO2 (M) after annealing at high purity N2 atmosphere. The DSC results exhibit a strong crystallographic transition, and the phase transition temperature of VO2 (M) can be reduced to about 38 °C by W-doping. Field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HR-TEM) were used to characterize the morphology and crystalline structure of the samples. The variable-temperature infrared transmittance spectra of VO2 (M) demonstrate their potential applications in energy saving field.

scholarly journals Tuning Anatase-Rutile Phase Transition Temperature: TiO2/SiO2 Nanoparticles Applied in Dye-Sensitized Solar Cells

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Billy N. Cardoso ◽  
Emerson C. Kohlrausch ◽  
Marina T. Laranjo ◽  
Edilson V. Benvenutti ◽  
Naira M. Balzaretti ◽  
...  
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Surface Area ◽  
Phase Transition Temperature ◽  
Dye Sensitized Solar Cells ◽  
Rutile Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Molar Percent

TiO2/SiO2 nanoparticles with 3, 5, and 10 molar percent of silica, were synthesized by hydrothermal method and characterized by SEM, TEM, N2 adsorption-desorption isotherms, X-ray diffraction, and Raman and UV-Vis spectroscopy. While pristine TiO2 thermally treated at 500°C presents a surface area of 36 m2 g-1 (±10 m2 g-1), TiO2/SiO2 containing 3, 5, and 10 molar percent of silica present surface areas of 93, 124, and 150 m2 g-1 (±10 m2 g-1), respectively. SiO2 is found to form very small amorphous domains well dispersed in the TiO2 matrix. X-ray diffraction and Raman spectroscopy data show that anatase-to-rutile phase transition temperature is delayed by the presence of SiO2, enabling single-anatase phase photoanodes for DSSCs. According to the I×V measurements, photoanodes with 3% of SiO2 result in improved efficiency, which is mainly related to increased surface area and dye loading. In addition, the results suggest a gain in photocurrent related to the passivation of defects by SiO2.

scholarly journals The Effect of Cobalt Doping in Structural Phase Transition of SmFe1-xCoxAsO Measured by Low-temperature X-ray Diffraction

2012 ◽  
Vol 4 (3) ◽  
pp. 541-550 ◽  
Author(s):  
A. Khan ◽  
A. Rahman ◽  
S. Naher ◽  
H. Kaneko ◽  
Y. Yun ◽  
...  
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Phase Transition Temperature ◽  
Structural Phase Transition ◽  
Structural Transition ◽  
Critical Concentration ◽  
Structural Phase ◽  
Parent Compound ◽  
X Ray Diffraction ◽  
X Ray

The parent compound SmFeAsO shows structural phase transition from tetragonal to orthorhombic at the temperature TD = 144 K. In the compound SmFe1-xCoxAsO,  with increasing x the structural transition temperature TD and  SDW TN decreases and reaches 0 K at the critical concentration xc. The X-ray diffraction technique has been used here to study the structural phase transition temperature. It is observed that the (400) peak of the parent compound SmFeAsO splits into two peaks (400) and (040), when the temperature is lower than the structural transition temperature TD. The structural phase transition of Co doped compounds SmFe1-xCoxAsO has also been studied for x = 0, 0.01, 0.025 and 0.075. The phase transition temperature TD for SmFe0.99Co0.01AsO, SmFe0.975Co0.025AsO and SmFe0.925Co0.075AsO are 134 K, 118 K and 4 K, respectively. The phase diagram of TD versus lattice spacing reveals that the structural transition temperature decreases with shrinking lattice constant along c-axis similar to the decrease of the structural phase transition temperature with increasing Co concentration. The phase diagrams of   SmFe1-xCoxAsO and Sm(O1-xFx)FeAs show a similar nature.© 2012 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi: http://dx.doi.org/10.3329/jsr.v4i3.10248 J. Sci. Res. 4 (3), 541-550 (2012)

Investigations on Dielectric phase transition behavior of Pb(Fe0.5-xScx)Nb0.5O3 Multiferroic Ceramics

MRS Advances ◽  
2016 ◽  
Vol 1 (9) ◽  
pp. 585-590
Author(s):  
Bandi Mallesham ◽  
Ranjith Ramadurai
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Phase Transition Temperature ◽  
Essential Feature ◽  
Low Frequency ◽  
Cation Ordering ◽  
X Ray Diffraction ◽  
Dielectric Phase ◽  
Diffraction Patterns ◽  
The Stability

ABSTRACTPhase pure Pb[(Fe0.5-xScx)Nb0.5]O3 [x = 0 to 0.5] multiferroic relaxors have been synthesized to study the effect of Sc on dielectric phase tansition. Rietveld refinement of x-ray diffraction patterns confirm that the structure transforms from monoclinic (Cm) to rhomobohedral (R3m) at x = 0.3. Absence of low frequency dielectric response in compositions with low Sc content attributed to interfacial polarizabilty arising due to differences in conductivities of grain and grain boundary. Moreover, value of diffusivity parameter (γ) of high of Sc content compositions is near to 2, confirms relaxor charactertistic of these compositions. However, an essential feature of relaxors i.e., frequency dependent dielectric permittivity as a function of temperature is observed only in x = 0.5 composition [Pb(Sc0.5Nb0.5)O3 (PSN)]. In addition, ferroelectric phase transition temperature (Tmax) increases initially at lower Sc content (upto x ≤ 0.25), and further drops beyond x ≥ 0.3. Such behavior of Tmax in these compositions is due to the onset of B'-B" local cation ordering at x = 0.3. High temperature Raman spectra of Pb(Sc0.5Nb0.5)O3 (x = 0.5) confirm the stability of cation ordering in compositions with high Sc content well above the phase transition temperature.

Study on the Microstructure and Storage Heat Performance of Mg-25Al-15Zn-xCu Alloys

2015 ◽  
Vol 1120-1121 ◽  
pp. 1104-1108
Author(s):  
Hong Yan Wen ◽  
Xiao Ming Fan ◽  
Xiao Min Cheng
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Phase Change ◽  
Latent Heat ◽  
Phase Transition Temperature ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Optical Microstructure ◽  
Solid Solution Matrix ◽  
And Storage

With the help of optical microstructure(OM), X-ray diffraction(XRD) and differential scanning calorimetry(DSC), the microstructure and storage heat performance of Mg-based phase change thermal storage alloys were investigated.The results show that the microstructure of Mg-25Al-15Zn-xCu (x=0, 2%, 8% and 14%, respectivly) alloys are mainly composed of primary crystal α (Mg) solid solution matrix, β-Mg17Al12, CuZn, MgAl2Cu and Mg32(Al,Zn)49 phases. The phase transition temperature of Mg-25Al-15Zn and Mg-25Al-15Zn-8Cu alloys ​​are 412.1 °C and 405.9 °C respectively; and phase change latent heat values of that were 175.4 J/g and 209.3 J/g. The addition of Cu led to the formation of new phase, reducing the phase transition temperature and increasing the value of phase change latent heat.

X-Ray Diffraction Study of the Phase Transition of the ${\rm Si}(111)(\sqrt{3} \times \sqrt{3})\mbox{-Ag}$ Surface

2003 ◽  
Vol 10 (02n03) ◽  
pp. 519-524 ◽  
Author(s):  
Toshio Takahashi ◽  
Hiroo Tajiri ◽  
Kazushi Sumitani ◽  
Koichi Akimoto ◽  
Hiroshi Sugiyama ◽  
...  
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Low Temperatures ◽  
Diffuse Scattering ◽  
Room Temperature ◽  
Bragg Reflection ◽  
Grazing Incidence ◽  
X Ray Diffraction ◽  
X Ray ◽  
Displacive Phase Transition

The structure of the [Formula: see text] surface was studied at both room temperature and a low temperature of 50 K using grazing incidence X-ray diffraction. At low temperatures diffuse scattering was observed in addition to Bragg reflection. Least squares analyses for Bragg reflections using anisotropic Debye–Waller factors show that the structure at 50 K is consistent with an inequivalent triangle (IET) model, while the structure at room temperature is explained by a honeycomb-chained triangle (HCT) model with strong anisotropic Debye–Waller factors. From the temperature dependence of diffuse scattering, the phase transition temperature Tc and critical exponent β were determined to be about 150 K and 0.27. Some Bragg intensities showed discontinuous changes in their first derivatives at Tc. The results favor a displacive phase transition rather than an order–disorder one.

X-ray structure analyses of chloranil above and below phase transition temperature

1997 ◽  
Vol 58 (9) ◽  
pp. 1375-1381 ◽  
Author(s):  
Y. Kubozono ◽  
T. Yoshida ◽  
H. Maeda ◽  
S. Kashino ◽  
H. Terauchi ◽  
...  
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Phase Transition Temperature ◽  
X Ray

Growth, crystalline quality and transition variation of ternary Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 ferroelectric crystals

2013 ◽  
Vol 03 (01) ◽  
pp. 1350003
Author(s):  
Linghang Wang ◽  
Zhuo Xu ◽  
Zhenrong Li ◽  
Yuhui Wan ◽  
Junjie Gao ◽  
...  
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Defect Density ◽  
Growth Direction ◽  
Middle Part ◽  
Rhombohedral Structure ◽  
Bulk Crystals ◽  
X Ray Diffraction ◽  
Rocking Curve ◽  
X Ray

Bulk crystals of high Curie temperature (TC)24 Pb ( In 1/2 Nb 1/2) O 3–43 Pb ( Mg 1/3 Nb 2/3) O 3–33 PbTiO 3 (24PIN–43PMN–33PT) with 55 mm in diameter and 130 mm in length were reproducibly grown by the bottom-seeded Bridgman method. The X-ray diffraction (XRD) spectrum indicated that the as-grown crystal was a single phase with rhombohedral structure at room temperature, the domain morphology and the phase transition sequence of R → T →C were observed, the full width at half maximum (FWHM) of X-ray rocking curve of (002) face was about 0.77°, and the defect density was inferred to 2.56 × 1010cm-2. The measured density of the as-grown crystals was very close to the theoretical one. Variation of the transition temperature of the as-grown crystals along the growth direction revealed that T C increased linearly along the growth direction and rhombohedral to tetrahedral phase transition temperature (T RT ) gradually decreased in the middle part of the ingot.

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