Probing disorder in high-pressure cubic tin (IV) oxide: a combined X-ray diffraction and absorption study

2019 ◽  
Vol 26 (4) ◽  
pp. 1245-1252 ◽  
Author(s):  
Daniel Sneed ◽  
John S. C. Kearney ◽  
Dean Smith ◽  
Jesse S. Smith ◽  
Changyong Park ◽  
...  
Keyword(s):  
High Pressure ◽  
Laser Heating ◽  
High Pressures ◽  
Transparent Conducting Oxide ◽  
Large Degree ◽  
X Ray Diffraction ◽  
Quality Of Data ◽  
X Ray ◽  
Direct Laser ◽  
Gap Opening

The transparent conducting oxide, SnO2, is a promising optoelectronic material with predicted tailorable properties via pressure-mediated band gap opening. While such electronic properties are typically modeled assuming perfect crystallinity, disordering of the O sublattice under pressure is qualitatively known. Here a quantitative approach is thus employed, combining extended X-ray absorption fine-structure (EXAFS) spectroscopy with X-ray diffraction, to probe the extent of Sn—O bond anharmonicities in the high-pressure cubic (Pa\bar{3}) SnO2 – formed as a single phase and annealed by CO2 laser heating to 2648 ± 41 K at 44.5 GPa. This combinational study reveals and quantifies a large degree of disordering in the O sublattice, while the Sn lattice remains ordered. Moreover, this study describes implementation of direct laser heating of non-metallic samples by CO2 laser alongside EXAFS, and the high quality of data which may be achieved at high pressures in a diamond anvil cell when appropriate thermal annealing is applied.

Monoclinic FeO at high pressures

2008 ◽  
Vol 223 (7/2008) ◽  
Author(s):  
Innokenty Kantor ◽  
Alexander Kurnosov ◽  
Catherine McCammon ◽  
Leonid Dubrovinsky
Keyword(s):  
High Pressure ◽  
Iron Oxide ◽  
Single Crystal ◽  
Diffraction Study ◽  
High Pressures ◽  
X Ray Diffraction ◽  
X Ray

AbstractA high-pressure quasi-single crystal X-ray diffraction study of a synthetic iron oxide Fe

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

Formation of two crystal modifications of Fe7C3−x at 5.5 GPa

2019 ◽  
Vol 52 (6) ◽  
pp. 1378-1384
Author(s):  
Sergey Gromilov ◽  
Anatoly Chepurov ◽  
Valeri Sonin ◽  
Egor Zhimulev ◽  
Aleksandr Sukhikh ◽  
...  
Keyword(s):  
High Pressure ◽  
High Pressures ◽  
Experimental Studies ◽  
X Ray Diffraction ◽  
High Iron Content ◽  
X Ray ◽  
High Pressure High Temperature ◽  
Micro Analysis ◽  
Crystal Modifications ◽  
High Pressure Apparatus

The Fe–C system, which is widely used to grow commercial high-pressure–high-temperature diamond monocrystals, is rather complicated due to the formation of carbides. The carbide Fe3C is a normal run product, but the pressure at which Fe7C3 carbide becomes stable is a subject of discussion. This paper demonstrates the synthesis of Fe7C3 carbide and its detailed study using single-crystal and powder X-ray diffraction, as well as electron probe micro-analysis and scanning electron microscopy. The experiments were performed using a multiple-anvil high-pressure apparatus of `split-sphere' (BARS) type at a pressure of 5.5 GPa and a temperature of 1623 K. Our results show that in the Fe–C system, in addition to diamond, a phase that corresponds to the Fe7C3 carbide was synthesized. This means that both carbides (Fe7C3 and Fe3C) are stable at 5.5 GPa. Two crystal phases are described, Fe14C6 and Fe28C12−x . Fe14C6 is based on the well known rhombic structure of Fe7C3, while Fe28C12−x has a different packing order of Fe6C polyhedrons. The results obtained in this study should be taken into account when synthesizing and growing diamond at high pressures and temperatures in metal–carbon systems with a high iron content, as well as when conducting experimental studies on the synthesis of diamond directly from carbide.

scholarly journals Study on the High-Pressure Behavior of Goethite up to 32 GPa Using X-Ray Diffraction, Raman, and Electrical Impedance Spectroscopy

Minerals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 99 ◽  
Author(s):  
Ruilian Tang ◽  
Jiuhua Chen ◽  
Qiaoshi Zeng ◽  
Yan Li ◽  
Xue Liang ◽  
...  
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Impedance Spectroscopy ◽  
Electrical Impedance ◽  
High Pressures ◽  
Structural Phase ◽  
Second Order ◽  
Electrical Impedance Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray

Goethite is a major iron-bearing sedimentary mineral on Earth. In this study, we conducted in situ high-pressure x-ray diffraction, Raman, and electrical impedance spectroscopy measurements of goethite using a diamond anvil cell (DAC) at room temperature and high pressures up to 32 GPa. We observed feature changes in both the Raman spectra and electrical resistance at about 5 and 11 GPa. However, the x-ray diffraction patterns show no structural phase transition in the entire pressure range of the study. The derived pressure-volume (P-V) data show a smooth compression curve with no clear evidence of any second-order phase transition. Fitting the volumetric data to the second-order Birch–Murnaghan equation of state yields V0 = 138.9 ± 0.5 Å3 and K0 = 126 ± 5 GPa.

Structural stability of WS2 under high pressure

2014 ◽  
Vol 28 (25) ◽  
pp. 1450168 ◽  
Author(s):  
Nirup Bandaru ◽  
Ravhi S. Kumar ◽  
Jason Baker ◽  
Oliver Tschauner ◽  
Thomas Hartmann ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
High Temperature ◽  
Structural Changes ◽  
High Pressures ◽  
Structural Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diamond Anvil ◽  
Heating Up

Structural behavior of bulk WS 2 under high pressure was investigated using synchrotron X-ray diffraction and diamond anvil cell up to 52 GPa along with high temperature X-ray diffraction and high pressure Raman spectroscopy analysis. The high pressure results obtained from X-ray diffraction and Raman analysis did not show any pressure induced structural phase transformations up to 52 GPa. The high temperature results show that the WS 2 crystal structure is stable upon heating up to 600°C. Furthermore, the powder X-ray diffraction obtained on shock subjected WS 2 to high pressures up to 10 GPa also did not reveal any structural changes. Our results suggest that even though WS 2 is less compressible than the isostructural MoS 2, its crystal structure is stable under static and dynamic compressions up to the experimental limit.

scholarly journals The solvothermal synthesis of γ-AlOOH nanoflakes and their compression behaviors under high pressures

RSC Advances ◽  
2017 ◽  
Vol 7 (9) ◽  
pp. 4904-4911 ◽  
Author(s):  
Xudong Zhou ◽  
Jian Zhang ◽  
Yanmei Ma ◽  
Hui Tian ◽  
Yue Wang ◽  
...  
Keyword(s):  
High Pressure ◽  
Synchrotron Radiation ◽  
Solvothermal Synthesis ◽  
High Pressures ◽  
X Ray Diffraction ◽  
X Ray ◽  
Radiation Angle

The compression behaviors of γ-AlOOH nanoflakes were investigated via in situ high pressure synchrotron radiation angle dispersive X-ray diffraction techniques.

X-ray diffraction investigations of CaF2 at high pressure

1992 ◽  
Vol 25 (5) ◽  
pp. 578-581 ◽  
Author(s):  
L. Gerward ◽  
J. S. Olsen ◽  
S. Steenstrup ◽  
M. Malinowski ◽  
S. Åsbrink ◽  
...  
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Synchrotron Radiation ◽  
High Pressures ◽  
Low Pressure ◽  
Single Crystal Sample ◽  
X Ray Diffraction ◽  
Crystal Sample ◽  
X Ray ◽  
Pressure Phase

Synchrotron-radiation X-ray diffraction studies of CaF2 at high pressures have been performed on a powder sample up to 45 GPa and on a single-crystal sample up to 9.4 GPa. The bulk modulus of the low-pressure phase was determined to be B 0 = 87 (5) GPa. A phase transition was observed at about 9.5 GPa. The transition is accompanied by a volume contraction of 11%. The high-pressure phase is orthorhombic PbCl2 type (space group Pbnm). The sample only partially reverts to the low-pressure phase upon release of pressure.

Size- and morphology-dependent structural transformations in anatase TiO2 nanowires under high pressures

2015 ◽  
Vol 93 (2) ◽  
pp. 165-172 ◽  
Author(s):  
Zhaohui Dong ◽  
Yang Song
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
High Pressures ◽  
Anatase Phase ◽  
X Ray Diffraction ◽  
Bulk Materials ◽  
Tio2 Nanowires ◽  
X Ray ◽  
Different Dimensions ◽  
Size And Morphology

Titanium dioxide (TiO2) nanowires with two different dimensions (i.e., <100 nm and ∼200 nm in diameter) were synthesized and studied under high pressure up to 37 GPa by Raman spectroscopy and synchrotron X-ray diffraction. Direct anatase to baddeleyite phase transitions were observed in both samples upon compression, but with different onset pressures. The observed phase transitions are in contrast to bulk TiO2, where the anatase phase transforms to α-PbO2 phase and then the baddeleyite phase. Compressibility of the anatase and baddeleyite phases was found different than both nanocrystals and the corresponding bulk materials. Our comparative study demonstrated not only that the morphology of TiO2 nanowire substantially influences the high pressure behaviors, but dimensions play a determining role in terms of transformation pressures, phase stability regions, and compressibility.

X-ray diffraction study of HgBa2CuO4+δ at high pressures

1997 ◽  
Vol 12 (2) ◽  
pp. 106-112
Author(s):  
Eduardo J. Gonzalez ◽  
Winnie Wong-Ng ◽  
Gasper J. Piermarini ◽  
Christian Wolters ◽  
Justin Schwartz
Keyword(s):  
High Pressure ◽  
Bulk Modulus ◽  
Pressure Range ◽  
High Pressures ◽  
Anisotropy Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Anisotropic Elastic ◽  
High Pressure Study

An in situ high pressure study using energy dispersive X-ray diffraction has been carried out on the polycrystalline high-Tc superconductor, HgBa2CuO4+δ (Hg-1201), to study its phase stability under pressure and also to measure its compressibility and bulk modulus. No evidence of pressure-induced polymorphism was found in the pressure range investigated, i.e., from 0.1 MPa (1 atm) to 5 GPa. The compound exhibited anisotropic elastic properties. The axial compressibility along the c axis was measured to be (3.96±0.35)×10−3GPa−1 and along the a axis (3.42±0.13)×10−3GPa−1, corresponding to an anisotropy ratio of 1.16±0.11. The bulk modulus was determined to be (94.7±4.2) GPa and, assuming a Poisson's ratio of 0.2, Young's modulus was estimated to be (170±8) GPa.

scholarly journals High Pressure Diffraction for the Geosciences at the Advanced Light Source

2014 ◽  
Vol 70 (a1) ◽  
pp. C1097-C1097
Author(s):  
Christine Beavers ◽  
Jason Knight ◽  
Bora Kalkan ◽  
Jinyuan Yan ◽  
Alastair MacDowell ◽  
...  
Keyword(s):  
High Pressure ◽  
Light Source ◽  
High Pressures ◽  
X Rays ◽  
X Ray Diffraction ◽  
User Friendliness ◽  
X Ray ◽  
Advanced Light Source ◽  
Diamond Anvil ◽  
Multiple Detectors

The Advanced Light Source, in concert with COMPRES, supports a superconducting bending magnet beamline devoted to extreme conditions diffraction. This facility, beamline 12.2.2, is aimed at the geoscience community, but is available to any who desire high pressures, high temperatures and hard X-rays. The latest development has been integrating single crystal x-ray diffraction for diamond anvil cells into the existing suite of high pressure powder diffraction and amorphous scattering techniques. Multiple heating techniques are available to the user, as well as multiple detectors, which can be chosen to best suit the sample. The current staff are dedicated to improving the user friendliness of the beamline; a difficult experiment need not to be further complicated by a difficult beamline. Beamline infrastructure, including recent advances and improvements, will be discussed.

Sign in / Sign up

Export Citation Format

Share Document