Pressure-temperature phase diagram ofLiBH4: Synchrotron x-ray diffraction experiments and theoretical analysis

2008 ◽  
Vol 77 (17) ◽  
Author(s):  
V. Dmitriev ◽  
Y. Filinchuk ◽  
D. Chernyshov ◽  
A. V. Talyzin ◽  
A. ilewski ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Theoretical Analysis ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Phase Diagram

TWO-PHASE NUCLEI IN PARAELECTRIC PHASE OF Pb1-x(Li1/2La1/2)x(Zr1-yTiy)O3 SOLID SOLUTIONS

2001 ◽  
Vol 15 (24n25) ◽  
pp. 3366-3368
Author(s):  
V. L. SOBOLEV ◽  
V. M. ISHCHUK
Keyword(s):  
Phase Transition ◽  
Phase Diagram ◽  
Paraelectric Phase ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
Two Phase ◽  
X Ray ◽  
Ordered Phases ◽  
Ti Content ◽  
Temperature Phase Diagram

The phase transition from the paraelectric phase to ordered phases in Pb1-x(Li1/2La1/2)x(Zr1-yTiy)O3 with compositions close to the ferroelectric - antiferroelectric - paraelectric triple point in the Ti-content - temperature phase diagram is studied. X-ray diffraction is used to identify two - phase (antiferroelectric and ferroelectric) nuclei embeded in a paraelectric matrix. The relation between these two-phase nuclei in paraelectric phase and the diffuseness of the phase transition is discussed.

scholarly journals Low-temperature phase diagram of Fe1+yTe studied using x-ray diffraction

2013 ◽  
Vol 88 (9) ◽  
Author(s):  
Cevriye Koz ◽  
Sahana Rößler ◽  
Alexander A. Tsirlin ◽  
Steffen Wirth ◽  
Ulrich Schwarz
Keyword(s):  
Phase Diagram ◽  
Low Temperature ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Low Temperature Phase ◽  
Temperature Phase Diagram

scholarly journals Pressure–Temperature Phase Diagram of Ta-H System up to 9 GPa and 600 °C

2021 ◽  
Vol 11 (15) ◽  
pp. 6719
Author(s):  
Hiroyuki Saitoh ◽  
Shigeyuki Takagi ◽  
Toyoto Sato ◽  
Shin-ichi Orimo
Keyword(s):  
Phase Diagram ◽  
High Pressure ◽  
Entropy Change ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
Hydrogenation Reactions ◽  
Pressure Synthesis ◽  
Temperature Phase Diagram ◽  
Clapeyron Slope

High-pressure hydrogenation behaviors of pure metals have not been investigated extensively, although intense research of hydrogenation reactions under high pressure has been conducted to find novel functional hydrides. The former provides us with valuable information for the high-pressure synthesis of novel functional hydrides. A pressure–temperature phase diagram of the Ta–H system has been determined using the in situ synchrotron radiation X-ray diffraction technique below 9 GPa and 600 °C in this study. At room temperature, the phase boundary obtained between distorted bcc TaH~1 and hcp TaH~2 was consistent with the previously reported transition pressure. The experimentally obtained Clapeyron slope can be explained via the entropy change caused by hydrogen evolution from TaH~2.

High-temperature phase equilibria in the system Zr–O–N

2006 ◽  
Vol 21 (2) ◽  
pp. 320-328 ◽  
Author(s):  
Alexandre Ermoline ◽  
Mirko Schoenitz ◽  
Edward L. Dreizin
Keyword(s):  
Phase Diagram ◽  
High Temperature ◽  
Invariant Point ◽  
High Temperature Phase ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Comparison Of The Results ◽  
Laser Heated ◽  
Scanning Electron

Powders of Zr, ZrO2, and ZrN were mixed and pressed to produce samples with different bulk stoichiometries in the ternary Zr–O–N systems. The samples were laser heated above melting, maintained at a high temperature, and quenched. The processed samples were cross-sectioned and studied using scanning electron microscopy, energy dispersive x-ray spectroscopy, and x-ray diffraction. The results pointed to the location of the ternary invariant point Liquid + Gas + ZrO2 + ZrN on the high-temperature portion of the Zr–ZrO2–ZrN phase diagram. The ternary liquidus in the Zr–O–N system was further constrained based on the comparison of the results obtained in this work with composition histories of zirconium particles burning in air reported earlier. Elemental analysis of nitrogen-rich inclusions found in the samples showed the existence of an extended compositional range for ternary solid Zr–O–N solutions. X-ray diffraction analysis of the quenched samples indicated that these solutions are likely to be derived from the ZrN phase. A preliminary outline of the subsolidus ternary Zr–ZrO2–ZrN phase diagram is constructed based on these findings and the interpretations of the well-known binary Zr–O and Zr–N phase diagrams.

Electrical Resistivity of Three Polymorphs of Basi2 and P-T Phase Diagram

1995 ◽  
Vol 402 ◽  
Author(s):  
M. Imai ◽  
T. Hirano
Keyword(s):  
Phase Diagram ◽  
Electrical Resistivity ◽  
High Pressures ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Resistivity Measurements ◽  
Type Semiconductor ◽  
T Phase

AbstractThis paper reports a pressure-temperature phase diagram for BaSi2 and evaluates the electrical resistivity of orthorhombic, cubic and trigonal BaSi2. In-situ X-ray diffraction measurements revealed the transition sequence of cubic and trigonal BaSi2 from orthorhombic BaSi2 at high pressures and high temperatures. The electrical resistivity measurements of three polymorphs show that the electrical properties depend on the crystal structure: orthorhombic BaSi2is an n-type semiconductor as previously reported; cubic BaSi2is an n-type semiconductor; trigonal BaSi2is a hole metal that shows superconductivity with an onset temperature of 6.8K.

The pressure-temperature phase diagram of URu2Si2 under hydrostatic conditions

2010 ◽  
Vol 1264 ◽  
Author(s):  
Nicholas Patrick Butch ◽  
Jason R. Jeffries ◽  
William J. Evans ◽  
Song Xue J. Chi ◽  
Juscelino B. Leao ◽  
...  
Keyword(s):  
Heavy Fermion ◽  
Applied Pressure ◽  
Temperature Limit ◽  
Temperature Phase ◽  
Zero Temperature ◽  
Antiferromagnetic Transition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hidden Order ◽  
Temperature Phase Diagram

AbstractThe pressure dependence of the hidden order phase of the heavy fermion superconductor URu2Si2 has been a subject of intense research since shortly after the discovery of the compound decades ago. Applied pressure increases the critical temperature of the paramagnetic / hidden order transition and brings about a transition to long-range antiferromagnetism. The reported pressures and temperatures of these phase boundaries vary between studies: 4 – 7 kbar at low temperature and 12 – 15 kbar at high temperature. We review experimental evidence that the measured values of pressure and temperature are very sensitive to the chosen pressure transmitting medium. Recent x-ray diffraction measurements suggest that the relative position of the silicon atom in the unit cell is changing as a function of pressure. Recent neutron diffraction measurements show that the zero-temperature limit of the hidden order / antiferromagnetic transition occurs at pressures greater than 7.5 kbar.

Electron Microscope study of commensurate-incommensurate phase transition in BaZnGeO4

1990 ◽  
Vol 48 (4) ◽  
pp. 172-173
Author(s):  
Naoki Yamamoto ◽  
Makoto Kikuchi ◽  
Tooru Atake ◽  
Akihiro Hamano ◽  
Yasutoshi Saito
Keyword(s):  
Phase Transition ◽  
Electron Microscope Study ◽  
Room Temperature ◽  
Hexagonal Lattice ◽  
Ferroelectric Materials ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Periodic Arrays ◽  
Modulation Wave Vector

BaZnGeO4 undergoes many phase transitions from I to V phase. The highest temperature phase I has a BaAl2O4 type structure with a hexagonal lattice. Recent X-ray diffraction study showed that the incommensurate (IC) lattice modulation appears along the c axis in the III and IV phases with a period of about 4c, and a commensurate (C) phase with a modulated period of 4c exists between the III and IV phases in the narrow temperature region (—58°C to —47°C on cooling), called the III' phase. The modulations in the IC phases are considered displacive type, but the detailed structures have not been studied. It is also not clear whether the modulation changes into periodic arrays of discommensurations (DC’s) near the III-III' and IV-V phase transition temperature as found in the ferroelectric materials such as Rb2ZnCl4.At room temperature (III phase) satellite reflections were seen around the fundamental reflections in a diffraction pattern (Fig.1) and they aligned along a certain direction deviated from the c* direction, which indicates that the modulation wave vector q tilts from the c* axis. The tilt angle is about 2 degree at room temperature and depends on temperature.

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