High-pressure experimental study on Rb2S: antifluorite to Ni2In-type phase transitions

2011 ◽  
Vol 67 (2) ◽  
pp. 109-115 ◽  
Author(s):  
David Santamaria-Perez ◽  
Angel Vegas ◽  
Claus Muehle ◽  
Martin Jansen
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
Type Structure ◽  
Gradual Transition ◽  
Structural Behaviour ◽  
Two Phase ◽  
Band Maximum ◽  
X Ray ◽  
Type Phase ◽  
Strong Luminescence

The high-pressure behaviour of dirubidium sulfide, Rb2S, with antifluorite-type structure under room conditions (space group Fm\bar 3 m) has been studied up to 8 GPa at room temperature using angle-dispersive X-ray powder diffraction in a diamond–anvil cell (DAC). X-ray measurements have allowed us to completely characterize two phase transitions upon compression: (i) to an anticotunnite-type structure (Pnma) at some pressure between 1 bar and 0.7 GPa, and (ii) to a Ni2In-type structure (P63/mmc) at 2.6 GPa. A gradual transition from the Pnma to the P63/mmc structures seems to occur between 2.6 and 4.5 GPa. These results are in excellent agreement with previous theoretical predictions. Strong luminescence is observed above 2.6 GPa (band maximum at 703 nm) when the transition to the Ni2In-type phase starts to occur, the band maximum showing a non-linear blue shift with pressure. The observed sequence of phase transitions in Rb2S is discussed in relation to the high-pressure structural behaviour of isomorphic sulfides and the structures are compared with the cationic arrays of their corresponding oxides (e.g. rubidium sulfate, in which the sulfide has been oxidized).

PHASE TRANSITION IN LAYERED PEROVSKITE LIKE MANGANATE Ca3Mn2O7 UNDER HIGH PRESSURE

2001 ◽  
Vol 15 (18) ◽  
pp. 2491-2497 ◽  
Author(s):  
J. L. ZHU ◽  
L. C. CHEN ◽  
R. C. YU ◽  
F. Y. LI ◽  
J. LIU ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Diamond Anvil Cell ◽  
The Other ◽  
Layered Perovskite ◽  
X Ray Diffraction ◽  
Two Phase ◽  
X Ray ◽  
Diamond Anvil

In situ high pressure energy dispersive X-ray diffraction measurements on layered perovskite-like manganate Ca 3 Mn 2 O 7 under pressures up to 35 GPa have been performed by using diamond anvil cell with synchrotron radiation. The results show that the structure of layered perovskite-like manganate Ca 3 Mn 2 O 7 is unstable under pressure due to the easy compression of NaCl-type blocks. The structure of Ca 3 Mn 2 O 7 underwent two phase transitions under pressures in the range of 0~35 GPa. One was at about 1.3 GPa with the crystal structure changing from tetragonal to orthorhombic. The other was at about 9.5 GPa with the crystal structure changing from orthorhombic back to another tetragonal.

scholarly journals A high-pressure single-crystal X-ray study of ZnSiO3 pyroxene: possible phase transitions at 19kbar and 51kbar.

1989 ◽  
Vol 14 (8) ◽  
pp. 383-387 ◽  
Author(s):  
Yasuhiro KUDOH ◽  
Hiroshi TAKEDA ◽  
Haruo OHASHI
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
Single Crystal ◽  
X Ray

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.

High-Pressure-Induced Phase Transitions in Pentaerythritol:  X-ray and Raman Studies

2005 ◽  
Vol 109 (47) ◽  
pp. 22581-22587 ◽  
Author(s):  
Zbigniew A. Dreger ◽  
Yogendra M. Gupta ◽  
Choong-Shik Yoo ◽  
Hyunchae Cynn
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
X Ray

High-Pressure Phase Transitions of Cubic Y 2 O 3 under High Pressures by In-situ Synchrotron X-Ray Diffraction

2019 ◽  
Vol 36 (4) ◽  
pp. 046103 ◽  
Author(s):  
Sheng Jiang ◽  
Jing Liu ◽  
Xiao-Dong Li ◽  
Yan-Chun Li ◽  
Shang-Ming He ◽  
...  
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
High Pressures ◽  
High Pressure Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Pressure Phase

scholarly journals Thermal evolution of the crystal structure and phase transitions of KNbO 3

2018 ◽  
Vol 5 (6) ◽  
pp. 180368 ◽  
Author(s):  
S. L. Skjærvø ◽  
K. Høydalsvik ◽  
A. B. Blichfeld ◽  
M.-A. Einarsrud ◽  
T. Grande
Keyword(s):  
Crystal Structure ◽  
Phase Transitions ◽  
Thermal Evolution ◽  
Dynamical Instability ◽  
X Ray Diffraction ◽  
Two Phase ◽  
X Ray ◽  
Cell Parameters ◽  
First Order ◽  
Heating And Cooling

The thermal evolution of the crystal structure and phase transitions of KNbO 3 were investigated by high-temperature powder X-ray diffraction and Rietveld refinement of the diffraction data. Two phase transitions from orthorhombic ( Amm 2) to tetragonal ( P 4 mm ) and from tetragonal to cubic ( P m 3 ¯ m ) were confirmed, both on heating and cooling. Both phase transitions are first order based on the observed hysteresis. The mixed displacive and order–disorder nature of the tetragonal to cubic transition is argued based on symmetry and apparent divergence of the atomic positions from pseudo-cubic values. The transition between the orthorhombic and tetragonal phase shows no temperature-dependence for atomic positions and only thermal expansion of the unit cell parameters and is thus discussed in relation to a lattice dynamical instability.

High-pressure neutron-diffraction studies of KH2PO4-type phase transitions as Tctends to ok

1991 ◽  
Vol 124 (1) ◽  
pp. 355-360 ◽  
Author(s):  
R. J. Nelmes ◽  
M. I. McMahon ◽  
R. O. Piltz ◽  
N. G. Wright
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
Neutron Diffraction ◽  
Type Phase

A microsecond time resolved x-ray absorption near edge structure synchrotron study of phase transitions in Fe undergoing ramp heating at high pressure

2014 ◽  
Vol 115 (9) ◽  
pp. 093513 ◽  
Author(s):  
C. Marini ◽  
F. Occelli ◽  
O. Mathon ◽  
R. Torchio ◽  
V. Recoules ◽  
...  
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
Time Resolved ◽  
Edge Structure ◽  
X Ray ◽  
X Ray Absorption
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