Phase Transitions and Ion Conductivity in NASICON-Type Compounds Li1±XZr2-XMX(PO4)3, M = Ta, Nb, Y, Sc, In

2006 ◽  
Vol 249 ◽  
pp. 255-262 ◽  
Author(s):  
I.A. Stenina ◽  
M.N. Kislitsyn ◽  
I.Yu. Pinus ◽  
S.M. Haile ◽  
Andrew B. Yaroslavtsev
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Ionic Conductivity ◽  
Impedance Spectroscopy ◽  
Rhombohedral Phase ◽  
Nasicon Structure ◽  
X Ray ◽  
7Li Nmr ◽  
Zirconium Phosphates ◽  
Lithium Zirconium

Ionic conductivity and phase transitions of lithium-zirconium phosphates, Li1±XZr2- XMX(PO4)3 (M = Ta, Nb, Y, Sc, In), with NASICON structure were studied using X-ray powder diffraction, calorimetry, 31P and 7Li NMR and impedance spectroscopy. Triclinic-rhombohedral phase transition in these materials occurs in a wide temperature range at coexistence of both phases. Unusual change of LiZr2(PO4)3 lattice parameters with temperature increase was found. During heating of this compound parameter “a” significantly decreases.

scholarly journals Ionic Conductivity and Phase Transition Behaviour in 4AgI-(1-)-2CuI System

2008 ◽  
Vol 2008 ◽  
pp. 1-4 ◽  
Author(s):  
Mohammed Hassan ◽  
Rfi Rafiuddin
Keyword(s):  
Phase Transition ◽  
Ionic Conductivity ◽  
Binary System ◽  
High Temperature Phase ◽  
Temperature Phase ◽  
Conductivity Measurements ◽  
Temperature Dependent ◽  
X Ray ◽  
Dsc Curves ◽  
Transition Behaviour

Samples of general formula 4AgI-(1-)-2CuI, , have been prepared and investigated by XRD, DSC, and temperature-dependent conductivity studies. X-ray diffractograms showed the presence of binary system consisting of AgI and in the sample . Cu-substituted samples showed very similar diffractograms to that of the pure compound which indicates that no effect for the substitution on the nature of the binary system. DSC curves showed the presence of phase transition whose temperature increased with ratio in the system. Ionic conductivity measurements confirmed the occurrence of the phase transition and showed that the high temperature phase is superionic conducting, whose conductivity increases with the increasing amount in the system.

Structural-phase transition in (Cu2Te)2−x(ZnTe)x at high temperature

2021 ◽  
pp. 2150113
Author(s):  
H. B. Gasimov ◽  
R. M. Rzayev
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
High Temperature ◽  
Single Crystals ◽  
Structural Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Range ◽  
Xrd Study ◽  
Xrd Method

Cu2Te single crystal was grown by the Bridgman method. X-ray diffraction (XRD) study of Cu2Te single crystals in the temperature range of 293–893 K was performed and possible phase transitions in the mentioned range of temperature have been investigated. (Cu2Te)[Formula: see text](ZnTe)[Formula: see text] single crystals also were grown with [Formula: see text], 0.05, 0.10 concentrations and structural properties of the obtained single crystals were investigated by the XRD method in the temperature range 293–893 K. Lattice parameters and possible phase transitions in the mention temperature range were determined for (Cu2Te)[Formula: see text](ZnTe)[Formula: see text] single crystals for [Formula: see text], 0.05, 0.10 concentrations.

Phase transitions in ReO3studied by high-pressure X-ray diffraction

2000 ◽  
Vol 33 (2) ◽  
pp. 279-284 ◽  
Author(s):  
J.-E. Jørgensen ◽  
J. Staun Olsen ◽  
L. Gerward
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
Powder Diffraction ◽  
Ambient Pressure ◽  
Rhombohedral Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oxygen Ions ◽  
Pressure Phase ◽  
Related Phase

ReO3has been studied at pressures up to 52 GPa by X-ray powder diffraction. The previously observed cubicIm3¯ high-pressure phase was shown to transform to a monoclinic MnF3-related phase at about 3 GPa. All patterns recorded above 12 GPa could be indexed on rhombohedral cells. The compressibility was observed to decrease abruptly at 38 GPa. It is therefore proposed that the oxygen ions are hexagonally close packed above this pressure, giving rise to two rhombohedral phases labelled I and II. The zero-pressure bulk moduliBoof the observed phases were determined and the rhombohedral phase II was found to have an extremely large value of 617 (10) GPa. It was found that ReO3transforms back to thePm3¯mphase found at ambient pressure.

scholarly journals Phase Transition in Di-oleoylphosphatidylglycerol/Monoolein Membranes due to Interactions of Positively Charged Peptides at their Lipid Membrane-Interface

1970 ◽  
Vol 45 (3) ◽  
pp. 219-224
Author(s):  
Shah Md Masum ◽  
Masahito Yamazaki
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Small Angle ◽  
Lipid Membrane ◽  
Cubic Phase ◽  
Membrane Interface ◽  
X Ray ◽  
X Ray Scattering ◽  
Charged Peptides ◽  
Positively Charged

To elucidate the factors that induce phase transitions in biomembranes due to interactions of proteins/peptides at the lipid membrane-interface, the effects of positively charged peptides on the cubic phase (Q229) of Dioleoylphosphatidylglycerol (DOPG)/Monoolein (MO) membranes were investigated. Small angle X-ray Scattering (SAXS) results revealed that 12 mol% DOPG/88 mol % MO membranes in excess water at 25°C is body centered cubic phase of crystallographic space group Im3m (Q229). In presence of peptide LLKKK, the lattices constant of Q229 phase was gradually decreased with an increase of peptide concentration and a phase transition from cubic (Q229) to cubic (Q224) phase occurred at R=0.080; (R= molar ratio of peptide to lipid). On the other hand the designed peptide WLFLLKKK and antimicrobial peptide Magainin-2 induced lamellar phase (Lα) in the same mixture membranes. These results indicate that the interactions of the these peptides with this mixture membrane are different: LLKKK induces electrostatic attractive interactions and that of WLFLLKKKK and Magainin-2 bound with the lipid membranes induce electrostatic repulsive interaction at the membrane-interface, might be the major factor inducing different phase transitions in 12 mol% DOPG/88mol% MO mixture membranes. Key words: Antimicrobial peptide Magain-2; Dioleoylphosphatidylglycerol; Monoolein; Cubic phases; Small angle X-ray Scattering DOI: 10.3329/bjsir.v45i3.6530Bangladesh J. Sci. Ind. Res. 45(3), 219-224, 2010

X-ray diffraction and Raman study of DL-alanine at high pressure: revision of phase transitions

2012 ◽  
Vol 68 (4) ◽  
pp. 412-423 ◽  
Author(s):  
Nikolay A. Tumanov ◽  
Elena V. Boldyreva
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Structural Phase ◽  
Group Symmetry ◽  
Second Phase ◽  
Structural Phase Transitions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Parameters ◽  
Raman Study

The effect of pressure on DL-alanine has been studied by X-ray powder diffraction (up to 8.3 GPa), single-crystal X-ray diffraction and Raman spectroscopy (up to ∼ 6 GPa). No structural phase transitions have been observed. At ∼ 1.5–2 GPa, cell parameters b and c become accidentally equal to each other, but the space-group symmetry does not change. There is no phase transition between 1.7 and 2.3 GPa, contrary to what has been reported earlier [Belo et al. (2010). Vibr. Spectrosc. 54, 107–111]. The presence of the second phase transition, which was claimed to appear within the pressure range from 6.0 to 7.3 GPa (Belo et al., 2010), is also argued. The changes in the Raman spectra have been shown to be continuous in all the pressure ranges studied.

Stability and Conductivity of Gd2((Mo1/3Mn2/3)xTi1-x)2O7

1997 ◽  
Vol 500 ◽  
Author(s):  
J. J. Sprague ◽  
O. Porat ◽  
H. L. Tuller
Keyword(s):  
Solid State ◽  
Ionic Conductivity ◽  
Impedance Spectroscopy ◽  
Stability Region ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Stability ◽  
Stability Limits ◽  
Composite Solid ◽  
Solid State Electrochemical Device

ABSTRACTA composite solid state electrochemical device, with (Gd1-xCax)2Ti2O7 serving as the electrolyte and Gd2(Ti1-xMox)2O7 (GT-Mo) as the anode has recently been proposed. The latter exhibits high levels of mixed conduction under reducing atmospheres, but decomposes at high Po2. We have recently succeeded in extending the stability limits of the GT-Mo to higher Po2 with the addition of Mn. In this study, we report on the conductivity and stability of Gd2((Mo13Mn2/3)xTi1-x)207 (GMMT) as a function of Po2, T, and composition utilizing impedance spectroscopy and x-ray diffraction. The addition of Mn extends the stability region of the material to Po2 = 1 atm with little change in the magnitude of the conductivity. Defect models explaining the dependence of the conductivity on oxygen partial pressure are presented. Preliminary results from the use of an electronic blocking sandwich cell used to isolate the ionic conductivity of GMMT are also presented.

Properties of New Superionic Compounds (NH4)6LiZr4-nHfnF23 (n=1, 3)

2018 ◽  
Vol 386 ◽  
pp. 305-308
Author(s):  
Anatoly Podgorbunsky ◽  
Tamara Antokhina ◽  
Sergey V. Gnedenkov
Keyword(s):  
Phase Transitions ◽  
Charge Transfer ◽  
Ionic Conductivity ◽  
Impedance Spectroscopy ◽  
Activation Energies ◽  
High Ionic Conductivity

The phase transitions and conductivity of novel compounds (NH4)6LiZr4-nHfnF23 (n = 1, 3) were studied by DSC and impedance spectroscopy. The structure and the activation energies of the charge transfer in these compounds were estimated. The high ionic conductivity of these fluorocomplexes reaches 10-2 S/cm at 453 K.

Investigation of Phase Transitions in Stacked GeTe/SnTe and Ge2Se3/SnTe Chalcogenide Films

2011 ◽  
Vol 687 ◽  
pp. 677-683 ◽  
Author(s):  
Fei Ming Bai ◽  
Huai Wu Zhang ◽  
Surendra Gupta ◽  
Santosh Kurinec
Keyword(s):  
Phase Transition ◽  
Solid Solution ◽  
Phase Transitions ◽  
Phase Change Memory ◽  
Thin Layers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Area Detector ◽  
Memory Applications ◽  
Change Memory

Phase transitions in stacked GeTe/SnTe and Ge2Se3/SnTe thin layers for potential phase-change memory applications have been investigated by X-ray diffraction using an area detector system and by scanning electron microscopy. The as-deposited underlying GeTe or Ge2Se3 layer is amorphous, whereas the top SnTe layer is crystalline. In GeTe/SnTe stack, the crystallization of GeTe phase occurs near 170°C, and upon further heating, GeTe phase disappears, followed by the formation of rocksalt-structured GexSn1-xTe solid solution. In Ge2Se3/SnTe stack, the phase transition starts with the separation of SnSe phase due to the migration of Sn ions into the Ge2Se3 layer. The migration of Sn ions and the formation of SnSe are believed to facilitate the crystallization of Ge2Se3 solid solution at ~360°C, which is much lower than the crystallization temperature of Ge2Se3, therefore consuming less power during the phase transition.

OBSERVATION OF PHASE TRANSITIONS AT THE (100) SURFACE OF Al-3 at.% Ag

1995 ◽  
Vol 02 (02) ◽  
pp. 141-145 ◽  
Author(s):  
E. WETLI ◽  
M. HOCHSTRASSER ◽  
D. PESCIA ◽  
M. ERBUDAK
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Photoelectron Spectroscopy ◽  
Short Range ◽  
Short Range Order ◽  
Elevated Temperatures ◽  
X Ray ◽  
First Order ◽  
First Order Phase Transition ◽  
First Order Phase

In the bulk binary alloy Al-3 at.% Ag , Ag 2 Al precipitates are formed below 410°C which are reversibly dissolved at elevated temperatures. We have followed this phase transition at a (100) surface as a function of temperature by monitoring the bandwidth of the Ag 4d states in X-ray photoelectron spectroscopy. Since the bandwidth measures the coordination number of the emitting atoms, it directly reveals the short-range order of the Ag atoms at the surface. The measurements show that the dissolution of the Ag -rich clusters starts at temperatures at least 100 K below the bulk transition, and the observed hysteresis behavior is indicative of a first-order phase transition at the surface.

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