Effect of Eu doping on room temperature phase and phase transition of Sr2SiO4:Eu2+ phosphor synthesized by polymerized complex method

2019 ◽  
Vol 133 ◽  
pp. 135-141 ◽  
Author(s):  
Siti Sarina Binti Nasir ◽  
Kouta Yakura ◽  
Noriyuki Horiuchi ◽  
Masaya Tsuta ◽  
Ariyuki Kato
Keyword(s):  
Phase Transition ◽  
Room Temperature ◽  
Complex Method ◽  
Temperature Phase ◽  
Polymerized Complex Method

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.

scholarly journals 127I NQR and Crystal Structure Studies of [N(CH3)4]2 CdI4

2000 ◽  
Vol 55 (1-2) ◽  
pp. 225-229 ◽  
Author(s):  
Hideta Ishihara ◽  
Keizo Horiuchi ◽  
Thorsten M. Gesing ◽  
Shi-qi Dou ◽  
J.-Christian Buhl ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Order Phase Transition ◽  
Intensity Ratio ◽  
Room Temperature ◽  
Liquid Nitrogen Temperature ◽  
Temperature Phase ◽  
First Order ◽  
First Order Phase Transition ◽  
First Order Phase

The temperature dependence of 127I NQR and DSC as well as the crystal structure at room temperature of the title compound were determined. This compound shows a first-order phase transition of an order-disorder type at 245 K. Eight 127I(v1:m = ±1/2 ↔ ±3/2) NQR lines of 79.57, 81.86, 82.56, 83.36, 84.68, 87.72, 88.34, and 88.86 MHz, and corresponding eight 127I(v2: m = ±3/2 ↔±5/2) NQR lines were observed at liquid nitrogen temperature. Three 127I(υi) NQR lines wfth an intensity ratio of 1:1:2 in the order of decreasing frequency were observed just above the transition point and two NQR lines except for the middle-frequency line disappeared around room temperature. This temperature behavior of NQR lines is very similar to that observed in [N(CH3)4]2Hgl4. Another first-order phase transition takes place at 527 K. The structure of the room-temperature phase was redetermined: orthorhombic, Pnma, Z = 4, a = 1342.8(3), b = 975.7(2), c = 1696.5(3) pm. The NQR result of three lines with an intensity ratio of 1:1:2 is in agreement with this structure. The thermal displacement parameters of atoms in both cations and anions are large.

DC Magnetron Sputtering Deposition of Room-Temperature Phase Transition Vanadium Oxide Film

2014 ◽  
Vol 1053 ◽  
pp. 332-336 ◽  
Author(s):  
Ya Qiao ◽  
Yuan Lu ◽  
Hua Yang ◽  
Yong Shun Ling
Keyword(s):  
Thin Film ◽  
Phase Transition ◽  
Magnetron Sputtering ◽  
Vanadium Oxide ◽  
Room Temperature ◽  
Annealed Film ◽  
Oxide Thin Film ◽  
Temperature Phase ◽  
Dc Magnetron Sputtering ◽  
Main Component

Low valence vanadium oxide thin film was deposited on ordinary glass substrates by direct current (DC) magnetron sputtering from a vanadium metal target. And then it was annealed in an atmosphere of oxygen/argon mixture at the temperature of 450°C for 2hours to obtain VO2thin film possessing the ability of phase transition. The XRD patterns and resistance-temperature (R-T) curves of the film before and after the annealing were given. The results show that: the as-deposited film, whose main component is V2O3, presents no phase transition and its resistance changes from 1.26 kΩ~1.01kΩ while its temperature rising from room temperature to 80°C; the annealed film, whose main component is VO2, presents a phase transition when its temperature rising from room temperature to 80°C and its resistance changes from 10kΩ to 60Ω, more than two orders. And the phase transition temperature of the film deposited is only 30°C.

Phase Transitions and Water Dynamics of [Mn(H2O)6](ClO4 )2 Studied by Differential Scanning Calorimetry and Neutron Scattering Methods

2000 ◽  
Vol 55 (9-10) ◽  
pp. 759-764 ◽  
Author(s):  
E. Mikuli ◽  
A. Migdał-Mikuli ◽  
I. Natkaniec ◽  
J. Mayer
Keyword(s):  
Phase Transition ◽  
Low Temperature ◽  
Neutron Scattering ◽  
Structural Phase Transition ◽  
Room Temperature ◽  
Structural Phase ◽  
Water Dynamics ◽  
Water Molecules ◽  
Temperature Phase ◽  
Solid Phases

Abstract DSC measurements performed at 95 -290 K have shown that [Mn(H 2 O) 6 ](CIO 4) 2 possesses, besides a high-temperature phase, existing above 323 K, four low-temperature solid phases. The inelastic incoherent neutron scattering (IINS) spectra and neutron powder diffraction (NPD) pat-terns registered at 20 -290 K have supported the DSC results and provided evidence that the investigated substance possesses even more than five solid phases. The IINS spectra have shown that in the room-temperature phase, water molecules perform fast stochastic reorientation at the picosecond scale. The orientational disorder characteristic for the room-temperature phase can be easily overcooled and frozen. Even by relatively slow cooling at ca. 40 K/hour a metastable, orientational (protonic) glass phase is formed below ca. 160 K. Below ca. 100 K, a structural phase transition was observed by the NPD, however the IINS spectra indicate existence of the pure ordered low-temperature phase only after annealing the sample for a few hours at 100 K. On heating, a structural phase transition takes place at ca. 120 K, and at ca. 225 K water molecules begin fast reorientation.

scholarly journals Room Temperature Phase Transition in Methylammonium Lead Iodide Perovskite Thin Films Induced by Hydrohalic Acid Additives

ChemSusChem ◽  
2016 ◽  
Vol 9 (18) ◽  
pp. 2656-2665 ◽  
Author(s):  
Chan Myae Myae Soe ◽  
Constantinos C. Stoumpos ◽  
Boris Harutyunyan ◽  
Eric F. Manley ◽  
Lin X. Chen ◽  
...  
Keyword(s):  
Thin Films ◽  
Phase Transition ◽  
Room Temperature ◽  
Temperature Phase ◽  
Lead Iodide ◽  
Temperature Phase Transition ◽  
Methylammonium Lead Iodide ◽  
Hydrohalic Acid

Kristallstruktur und thermische Phasenumwandlung von Tetramethylammoniumcyanid, (CH3)4N+CN- / Crystal Structure and Thermal Phase Transition of Tetramethylammonium Cyanide, (CH3)4N+CN-

1999 ◽  
Vol 54 (3) ◽  
pp. 372-376 ◽  
Author(s):  
Andreas Komath ◽  
Oliver Blecher
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Room Temperature ◽  
Temperature Phase ◽  
Cyanide Ion ◽  
Space Group ◽  
Disorder Transition ◽  
Thermal Phase Transition ◽  
Cell Dimensions ◽  
Thermal Phase

Tetramethylammonium cyanide crystallizes in the tetragonal space group P4/nmm, Z = 2, with cell dimensions a = 773.6(1), c = 546.8(1) pm. The cyanide ion is disordered in the plane perpendicular to the c-axis indicating a rotation. The room temperature phase undergoes a thermal phase transition at -59.9°C probably caused by an order-disorder transition of the cyanide ion.

scholarly journals Combinatorial discovery of small-molecule 1,2,3-triazolium ionic liquids exhibiting lower critical solution temperature phase transition

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yen-Ho Chu ◽  
Mou-Fu Cheng ◽  
Yung-Hsin Chiang
Keyword(s):  
Phase Transition ◽  
Ionic Liquid ◽  
Ionic Liquids ◽  
Phase Transitions ◽  
Small Molecule ◽  
Room Temperature ◽  
Solution Temperature ◽  
Temperature Phase ◽  
Critical Solution Temperature ◽  
True Value

Abstract Both lower and upper critical solution temperature (LCST and UCST) systems are two typical phase behaviors of thermoresponsive materials with solvents, in which LCST is far less common than UCST. Recent studies on ionic liquids carrying LCST phase transitions have predominantly focused on quaternary ammonium- and phosphonium-based ionic salts. Based on the 1,2,3-triazole core structure assemblable by azide-alkyne cycloaddition click reaction, this work reports the combinatorial synthesis of 1,3,4-trialkylated 1,2,3-triazolium ionic liquids in three libraries with a total of 160 ionic liquids and demonstrates, for the first time, their values in temperature-switchable phase transition with water. In this work, the successful discovery of a new thermoresponsive ionic liquid b26, based on the structure-and-phase separation study of b8 and b9, perfectly exemplified the true value of the tunability of ionic liquid fine structures. For all 160 ionic liquids synthesized, 155 are liquid at room temperature and 22 room-temperature ionic liquids were found to exhibit thermoresponsive phase transitions having low Tc values in water. To the best of our knowledge, this comprehensive study is the first report of small-molecule 1,2,3-triazolium ionic liquids that exhibit LCST property in water.

Room-temperature phase transition in Rb2CoCl4. heat capacity measurements

1986 ◽  
Vol 95 (2) ◽  
pp. K101-K103 ◽  
Author(s):  
P. Vaněk ◽  
B. Březina ◽  
M. Havránková ◽  
J. Biroš
Keyword(s):  
Phase Transition ◽  
Heat Capacity ◽  
Room Temperature ◽  
Temperature Phase ◽  
Temperature Phase Transition ◽  
Heat Capacity Measurements
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