scholarly journals High‐pressure–low‐temperature apparatus for NMR study of phase transitions

1982 ◽  
Vol 53 (11) ◽  
pp. 1724-1726 ◽  
Author(s):  
Paul J. Schuele ◽  
V. Hugo Schmidt
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
Low Temperature ◽  
Nmr Study

Probing Phase Transitions and Magnetism in Minerals with Neutrons

Elements ◽  
2021 ◽  
Vol 17 (3) ◽  
pp. 181-188 ◽  
Author(s):  
Bryan C. Chakoumakos ◽  
John B. Parise
Keyword(s):  
Magnetic Field ◽  
High Pressure ◽  
Phase Transitions ◽  
Low Temperature ◽  
Structural Phase ◽  
Neutron Sources ◽  
Control Temperature ◽  
Temperature Capability ◽  
Recent Developments ◽  
High Pressure Apparatus

The development of sophisticated sample environments to control temperature, pressure, and magnetic field has grown in parallel with neutron source and instrumentation development. High-pressure apparatus, with high- and low-temperature capability, novel designs for diamond cells, and large volume presses are matched with next-generation neutron sources and moderator designs to provide unprecedented neutron beam brightness. Recent developments in sample environments are expanding the pressure–temperature space accessible to neutron scattering experiments. Researchers are using new capabilities and an increased understanding of the fundamentals of structural and magnetic transitions to explore new territories, including hydrogenous minerals (e.g., ices and hydrates) and magnetic structural phase diagrams.

Influence of the molecular structures on the high-pressure and low-temperature phase transitions of plastic crystals

2003 ◽  
Vol 59 (1) ◽  
pp. 60-71 ◽  
Author(s):  
Markus Wunschel ◽  
Robert E. Dinnebier ◽  
Stefan Carlson ◽  
Piotr Bernatowicz ◽  
Sander van Smaalen
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
Low Temperature ◽  
Room Temperature ◽  
Close Packing ◽  
Molecular Structures ◽  
Temperature Phase ◽  
Plastic Crystals ◽  
First Order ◽  
First Order Phase

The crystal structures of tert-butyl-tris(trimethylsilyl)silane, Si[C(CH_3)_3]_1[Si(CH_3)_3]_3 (Bu1), and di-tert-butyl-bis(trimethylsilyl)silane, Si[C(CH_3)_3]_2[Si(CH_3)_3]_2 (Bu2), at room temperature and at 105 K have been determined by X-ray powder diffraction; the high-pressure behavior for pressures between 0 and 5 GPa is reported. The room-temperature structures have cubic Fm\bar{3}m symmetry (Z = 4) with a = 13.2645 (2) Å, V = 2333.87 (4) Å3 for Bu1 and a = 12.9673 (1) Å, V = 2180.46 (3) Å3 for Bu2. The molecules are arranged in a cubic close packing (c.c.p.) and exhibit at least 48-fold orientational disorder. Upon cooling both compounds undergo a first-order phase transition at temperatures T_c = 230 (5) K (Bu1) and T_c = 250 (5) K (Bu2) into monoclinic structures with space group P2_1/n. The structures at 105 K have a = 17.317 (1), b = 15.598 (1), c = 16.385 (1) Å, \gamma = 109.477 (4)°, V = 4172.7 (8) Å3 and Z = 8 for Bu1and a = 17.0089 (9), b = 15.3159 (8), c = 15.9325 (8) Å, \gamma = 110.343 (3)°, V = 3891.7 (5) Å3 and Z = 8 for Bu2. The severe disorder of the room-temperature phase is significantly decreased and only a two- or threefold rotational disorder of the molecules remains at 105 K. First-order phase transitions have been observed at pressures of 0.13–0.28 GPa for Bu1 and 0.20–0.24 GPa for Bu2. The high-pressure structures are isostructural to the low-temperature structures. The pressure dependencies of the unit-cell volumes were fitted with Vinet equations of state and the bulk moduli were obtained. At still higher pressures further anomalies in the pressure dependencies of the lattice parameters were observed. These anomalies are explained as additional disorder–order phase transitions.

High-pressure, low-temperature studies of phase transitions in SrRuO3 – Absence of volume collapse

2020 ◽  
Vol 287 ◽  
pp. 121360
Author(s):  
Camilla Hjort Kronbo ◽  
Louise Ring Jensen ◽  
Francesca Menescardi ◽  
Davide Ceresoli ◽  
Martin Bremholm
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
Low Temperature ◽  
Volume Collapse

Phase transitions in black phosphorus at low temperature and high pressure

1990 ◽  
Vol 144 (2) ◽  
pp. 102-104 ◽  
Author(s):  
I. Shirotani ◽  
K. Tsuji ◽  
M. Imai ◽  
H. Kawamura ◽  
O. Shimomura ◽  
...  
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
Low Temperature ◽  
Black Phosphorus

Cavity hydration as a gateway to unfolding: An NMR study of hen lysozyme at high pressure and low temperature

2011 ◽  
Vol 156 (1) ◽  
pp. 24-30 ◽  
Author(s):  
Yuji O. Kamatari ◽  
Lorna J. Smith ◽  
Christopher M. Dobson ◽  
Kazuyuki Akasaka
Keyword(s):  
High Pressure ◽  
Low Temperature ◽  
Nmr Study
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