Electronic Phase Transitions in F-electron Metals at High Pressures: Synchrotron X-ray Spectroscopic Studies on GD to 100 GPa

2008 ◽  
Vol 1104 ◽  
Author(s):  
Choong-Shik Yoo ◽  
Brian Maddox ◽  
Valentin Iota
Keyword(s):  
High Pressure ◽  
Electronic Structure ◽  
Phase Transitions ◽  
Electron Correlation ◽  
High Pressures ◽  
Spectroscopic Studies ◽  
Strong Electron ◽  
X Ray ◽  
Volume Collapse ◽  
Highly Correlated

AbstractUnusual phase transitions driven by electron correlation effects occur in many f-electron metals (lanthanides and actinides alike) from localized phases to itinerant phases at high pressures. The dramatic changes in atomic volumes and crystal structures associated with some of these transitions signify equally important changes in the underlying electronic structure of these correlated f-electron metals. Yet, the relationships among the crystal structure, electronic correlation and electronic structure in f-electron metals have not been well understood. In this study, utilizing recent advances in third-generation synchrotron x-ray spectroscopies and high-pressure diamond-anvil cell technologies, we describe the pressure-induced spectral changes across the volume collapse transition in Gd at 60 GPa and well above. The spectral results suggest that the f-electrons of high-pressure Gd phases are highly correlated even at 100 GPa – consistent with the Kondo volume collapse model and the recent experimental evidence of strong electron correlation of α-Ce.

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 X-Ray Diffraction and Electron Microscopy Studies of the Size Effects on Pressure-Induced Phase Transitions in CdS Nanocrystals

MRS Advances ◽  
2020 ◽  
pp. 1-9
Author(s):  
Lingyao Meng ◽  
Hongyou Fan ◽  
J. Matthew Lane ◽  
Luke Baca ◽  
Jackie Tafoya ◽  
...  
Keyword(s):  
Phase Transition ◽  
Particle Size ◽  
High Pressure ◽  
Phase Transitions ◽  
Size Effects ◽  
High Pressures ◽  
Bulk Material ◽  
Cds Nanoparticles ◽  
X Ray ◽  
Potential Applications

Abstract In recent years, investigations of the phase transition behavior of semiconducting nanoparticles under high pressure has attracted increasing attention due to their potential applications in sensors, electronics, and optics. However, current understanding of how the size of nanoparticles influences this pressure-dependent property is somewhat lacking. In particular, phase behaviors of semiconducting CdS nanoparticles under high pressure have not been extensively reported. Therefore, in this work, CdS nanoparticles of different sizes are used as a model system to investigate particle size effects on high-pressure-induced phase transition behaviors. In particular, 7.5, 10.6, and 39.7 nm spherical CdS nanoparticles are synthesized and subjected to controlled high pressures up to 15 GPa in a diamond anvil cell. Analysis of all three nanoparticles using in-situ synchrotron wide-angle X-ray scattering (WAXS) data shows that phase transitions from wurtzite to rocksalt occur at higher pressures than for bulk material. Bulk modulus calculations not only show that the wurtzite CdS nanomaterial is more compressible than rocksalt, but also that the compressibility of CdS nanoparticles depends on their particle size. Furthermore, sintering of spherical nanoparticles into nanorods was observed for the 7.5 nm CdS nanoparticles. Our results provide new insights into the fundamental properties of nanoparticles under high pressure that will inform designs of new nanomaterial structures for emerging applications.

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.

Magnetic Collapse and Insulator-Metal Transitions in Some 3D Metal Oxides Under High Pressures

2006 ◽  
Vol 987 ◽  
Author(s):  
Igor S. Lyubutin ◽  
Alexander G. Gavriliuk ◽  
Viktor Struzhkin
Keyword(s):  
High Pressure ◽  
Metal Oxides ◽  
High Pressures ◽  
Structural Phase ◽  
X Ray Diffraction ◽  
Strong Electron ◽  
X Ray ◽  
Strong Electron Correlations ◽  
Synchrotron Radiation Techniques ◽  
Localized Magnetic Moment

AbstractIn the systems with strong electron correlations, many theories predict the high-pressure-induced dielectric-metal transition, which is followed by collapse of localized magnetic moment and structural phase transition. In this report, summary results of many last experiments on the influence of high pressure on the magnetic and crystal structure as well on the electronic and transport properties of 3d metal oxides is presented. Along with X-ray diffraction, optical absorption, Raman scattering and electroresistivity measurements, several synchrotron radiation techniques have also been applied to perform the high-pressure experiments with compound iron oxides having different crystal structures.

High pressure phase transitions in organic solids II: X-ray diffraction study ofp-dichlorobenzene at high pressures

Pramana ◽  
1986 ◽  
Vol 27 (6) ◽  
pp. 835-839 ◽  
Author(s):  
Hema Sankaran ◽  
Surinder M Sharma ◽  
S K Sikka ◽  
R Chidambaram
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
Diffraction Study ◽  
High Pressures ◽  
High Pressure Phase ◽  
X Ray Diffraction ◽  
Organic Solids ◽  
X Ray ◽  
Pressure Phase

High-pressure crystal chemistry of binary intermetallic compounds

2006 ◽  
Vol 221 (5-7) ◽  
Author(s):  
Roman Demchyna ◽  
Stefano Leoni ◽  
Helge Rosner ◽  
Ulrich Schwarz
Keyword(s):  
High Pressure ◽  
Electronic Structure ◽  
Phase Transitions ◽  
Intermetallic Compound ◽  
Intermetallic Compounds ◽  
High Pressures ◽  
Structural Transformations ◽  
Pressure Effects ◽  
Zintl Phases ◽  
Bonding Properties

AbstractEffects of high pressure on intermetallic compounds are reviewed with regards to structural stability and phase transitions. Changes of bonding properties and electronic structure are examplified by means of the elemental metals caesium and titanium, the latter forming an internal intermetallic compound at high pressures. After a short systematic overview regarding pressure effects, structural transformations in selected classes of intermetallic compounds like Zintl phases and AlB

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

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.

Sign in / Sign up

Export Citation Format

Share Document