Low temperature frustrated structural phase transition in single crystal La1.85Sr0.15CuO4

1995 ◽  
Vol 197 (5-6) ◽  
pp. 439-443 ◽  
Author(s):  
Z.J. Yang ◽  
M. Yewondwossen ◽  
R.A. Dunlap ◽  
D.J.W. Geldart ◽  
S.L. Yuan ◽  
...  
Keyword(s):  
Phase Transition ◽  
Low Temperature ◽  
Single Crystal ◽  
Structural Phase Transition ◽  
Structural Phase

Low-Temperature Structure (T = 235 K) and Structural Phase Transition in [(C2H5)4N]2SnCl6

1987 ◽  
Vol 103 (1) ◽  
pp. 73-78 ◽  
Author(s):  
H. Ketata ◽  
M. H. Ben Ghozlen ◽  
A. Daoud ◽  
I. Pabst
Keyword(s):  
Phase Transition ◽  
Low Temperature ◽  
Structural Phase Transition ◽  
Structural Phase ◽  
Temperature Structure

scholarly journals Phase transition and proton ordering at 50 K in 3-(pyridin-4-yl)pentane-2,4-dione

2017 ◽  
Vol 73 (6) ◽  
pp. 1172-1178 ◽  
Author(s):  
Khai-Nghi Truong ◽  
Carina Merkens ◽  
Martin Meven ◽  
Björn Faßbänder ◽  
Richard Dronskowski ◽  
...  
Keyword(s):  
Phase Transition ◽  
Low Temperature ◽  
Single Crystal ◽  
Structural Phase ◽  
Pyridyl Ring ◽  
Temperature Phase ◽  
Crystallographic Axis ◽  
Temperature Phase Transition ◽  
Intramolecular Hydrogen ◽  
Low Temperature Phase

Single-crystal neutron diffraction experiments at 100 and 2.5 K have been performed to determine the structure of 3-(pyridin-4-yl)pentane-2,4-dione (HacacPy) with respect to its protonation pattern and to monitor a low-temperature phase transition. Solid HacacPy exists as the enol tautomer with a short intramolecular hydrogen bond. At 100 K, its donor···acceptor distance is 2.450 (8) Å and the compound adopts space group C2/c, with the N and para-C atoms of the pyridyl ring and the central C of the acetylacetone substituent on the twofold crystallographic axis. As a consequence of the axial symmetry, the bridging hydrogen is disordered over two symmetrically equivalent positions, and the carbon–oxygen bond distances adopt intermediate values between single and double bonds. Upon cooling, a structural phase transition to the t 2 subgroup P\bar 1 occurs; the resulting twins show an ordered acetylacetone moiety. The phase transition is fully reversible but associated with an appreciable hysteresis in the large single crystal under study: transition to the low-temperature phase requires several hours at 2.5 K and heating to 80 K is required to revert the transformation. No significant hysteresis is observed in a powder sample, in agreement with the second-order nature of the phase transition.

Structural phase transition at low temperature in La2−x Sr x CuO4 aroundx=0.12 under magnetic fields

1996 ◽  
Vol 46 (S3) ◽  
pp. 1237-1238 ◽  
Author(s):  
Takao Suzuki ◽  
Kaichiro Chiba ◽  
Takayuki Goto ◽  
Tetsuo Fukase
Keyword(s):  
Phase Transition ◽  
Low Temperature ◽  
Magnetic Fields ◽  
Structural Phase Transition ◽  
Structural Phase

Effects of partial substitution on Tc and low-temperature structural phase transition in La2−xBaxCuO4

1991 ◽  
Vol 185-189 ◽  
pp. 791-792 ◽  
Author(s):  
Yoji Koike ◽  
Tsutomu Kawaguchi ◽  
Syoichi Hosoya ◽  
Naoki Watanabe ◽  
Takahashi Noji ◽  
...  
Keyword(s):  
Phase Transition ◽  
Low Temperature ◽  
Structural Phase Transition ◽  
Structural Phase ◽  
Partial Substitution

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.

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