scholarly journals Possible quantum fluctuations in the vicinity of the quantum critical point of (Sr,Ca)3Ir4Sn13 revealed by high-energy x-ray diffraction

2020 ◽  
Vol 101 (10) ◽  
Author(s):  
L. S. I. Veiga ◽  
J. R. L. Mardegan ◽  
M. v. Zimmermann ◽  
D. T. Maimone ◽  
F. B. Carneiro ◽  
...  
Keyword(s):  
Critical Point ◽  
Quantum Critical Point ◽  
Quantum Fluctuations ◽  
High Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Quantum Critical

Charge redistribution and a shortening of the Fe—As bond at the quantum critical point of SmO1–xFxFeAs

2015 ◽  
Vol 22 (4) ◽  
pp. 1030-1034 ◽  
Author(s):  
Jie Cheng ◽  
Peng Dong ◽  
Wei Xu ◽  
Shengli Liu ◽  
Wangsheng Chu ◽  
...  
Keyword(s):  
Critical Point ◽  
Quantum Critical Point ◽  
Charge Redistribution ◽  
Edge Structure ◽  
X Ray ◽  
Feas Layer ◽  
Shoulder Peak ◽  
Quantum Critical ◽  
X Ray Absorption ◽  
Evident Relationship

Many researchers have pointed out that there is a quantum critical point (QCP) in the F-doped SmOFeAs system. In this paper, the electronic structure and local structure of the superconductive FeAs layer in SmO1–xFxFeAs as a function of the F-doping concentration have been investigated using Fe and AsK-edge X-ray absorption spectroscopy. Experiments performed on the X-ray absorption near-edge structure showed that in the vicinity of the QCP the intensity of the pre-edge feature at the Fe-edge decreases continuously, while there is a striking rise of the shoulder-peak at the As edge, suggesting the occurrence of charge redistribution near the QCP. Further analysis on the AsK-edge extended X-ray absorption fine structure demonstrated that the charge redistribution originates mostly from a shortening of the Fe—As bond at the QCP. An evident relationship between the mysterious QCP and the fundamental Fe—As bond was established, providing new insights on the interplay between QCP, charge dynamics and the local structural Fe—As bond in Fe-based superconductors.

scholarly journals 4f-Derived Fermi Surfaces ofCeRu2(Si1−xGex)2near the Quantum Critical Point: Resonant Soft-X-Ray ARPES Study

2009 ◽  
Vol 102 (21) ◽  
Author(s):  
T. Okane ◽  
T. Ohkochi ◽  
Y. Takeda ◽  
S.-i. Fujimori ◽  
A. Yasui ◽  
...  
Keyword(s):  
Critical Point ◽  
Quantum Critical Point ◽  
Fermi Surfaces ◽  
X Ray ◽  
Quantum Critical

Intermediate-Valence Behavior of YbCu5-xAlxaround Quantum Critical Point Measured by Resonant Inelastic X-ray Scattering at YbL3Absorption Edge

2007 ◽  
Vol 76 (12) ◽  
pp. 124705 ◽  
Author(s):  
Kazuya Yamamoto ◽  
Hitoshi Yamaoka ◽  
Naohito Tsujii ◽  
Aurel Mihai Vlaicu ◽  
Hirofumi Oohashi ◽  
...  
Keyword(s):  
Critical Point ◽  
Quantum Critical Point ◽  
Intermediate Valence ◽  
X Ray ◽  
X Ray Scattering ◽  
Quantum Critical ◽  
Ray Scattering

scholarly journals Evolution of Quantum Fluctuations Near the Quantum Critical Point of the Transverse Field Ising Chain SystemCoNb2O6

2014 ◽  
Vol 4 (3) ◽  
Author(s):  
A. W. Kinross ◽  
M. Fu ◽  
T. J. Munsie ◽  
H. A. Dabkowska ◽  
G. M. Luke ◽  
...  
Keyword(s):  
Critical Point ◽  
Quantum Critical Point ◽  
Transverse Field ◽  
Quantum Fluctuations ◽  
Ising Chain ◽  
Quantum Critical

THE STRAIN QUANTUM CRITICAL POINT FOR SUPERSTRIPES IN THE PHASE DIAGRAM OF ALL CUPRATE PEROVSKITES

2000 ◽  
Vol 14 (29n31) ◽  
pp. 3342-3355 ◽  
Author(s):  
A. BIANCONI ◽  
N. L. SAINI ◽  
S. AGRESTINI ◽  
D. DI CASTRO ◽  
G. BIANCONI
Keyword(s):  
Critical Temperature ◽  
Critical Point ◽  
Quantum Critical Point ◽  
Metallic Phase ◽  
X Ray Diffraction ◽  
Critical Fluctuations ◽  
Local Lattice ◽  
Lattice Distortions ◽  
Quantum Critical ◽  
Function Of Two Variables

The metallic phase in doped cuprate perovskites is determined by both the hope doping δ and the micro-strain ε of the planar Cu-O bond length. The micro-strain ε in the CuO 2 plane has been measured by Cu K-edge EXAFS and x-ray diffraction using synchrotron radiation. The critical micro-strain ε c for the onset of local lattice distortions (LLD) and stripe formation has been determined. The strain quantum critical point (QCP) is found at (ε c ,δ c ). The superconducting critical temperature is measured as a function of two variables T c (ε,δ) and it reaches its maximum at the strain QCP. The superconducting phase occurs in the region of critical fluctuations around this QCP. The critical fluctuations near the strain QCP drives the self-organization of the metallic plane forming a particular superlattice of quantum stripes called "superstripes" that favors the amplification of the superconducting critical temperature.

Characterizations of Synthetic 8mol% YSZ with Comparison to 3mol %YSZ for HT-SOFC

2020 ◽  
Vol 38 (4A) ◽  
pp. 491-500
Author(s):  
Abeer F. Al-Attar ◽  
Saad B. H. Farid ◽  
Fadhil A. Hashim
Keyword(s):  
Ionic Conductivity ◽  
Electrochemical Impedance ◽  
Structural Information ◽  
Impedance Analysis ◽  
High Energy ◽  
Yttria Stabilized Zirconia ◽  
X Ray Diffraction ◽  
Stabilized Zirconia ◽  
Powder Morphology ◽  
X Ray

In this work, Yttria (Y2O3) was successfully doped into tetragonal 3mol% yttria stabilized Zirconia (3YSZ) by high energy-mechanical milling to synthesize 8mol% yttria stabilized Zirconia (8YSZ) used as an electrolyte for high temperature solid oxide fuel cells (HT-SOFC). This work aims to evaluate the densification and ionic conductivity of the sintered electrolytes at 1650°C. The bulk density was measured according to ASTM C373-17. The powder morphology and the microstructure of the sintered electrolytes were analyzed via Field Emission Scanning Electron Microscopy (FESEM). The chemical analysis was obtained with Energy-dispersive X-ray spectroscopy (EDS). Also, X-ray diffraction (XRD) was used to obtain structural information of the starting materials and the sintered electrolytes. The ionic conductivity was obtained through electrochemical impedance spectroscopy (EIS) in the air as a function of temperatures at a frequency range of 100(mHz)-100(kHz). It is found that the 3YSZ has a higher density than the 8YSZ. The impedance analysis showed that the ionic conductivity of the prepared 8YSZ at 800°C is0.906 (S.cm) and it was 0.214(S.cm) of the 3YSZ. Besides, 8YSZ has a lower activation energy 0.774(eV) than that of the 3YSZ 0.901(eV). Thus, the prepared 8YSZ can be nominated as an electrolyte for the HT-SOFC.

scholarly journals In-Situ High-Energy X-ray Diffraction Study of Austenite Decomposition During Rapid Cooling and Isothermal Holding in Two HSLA Steels

2021 ◽  
Vol 52 (5) ◽  
pp. 1812-1825
Author(s):  
Sen Lin ◽  
Ulrika Borggren ◽  
Andreas Stark ◽  
Annika Borgenstam ◽  
Wangzhong Mu ◽  
...  
Keyword(s):  
Isothermal Holding ◽  
Weight Percent ◽  
High Energy ◽  
Decomposition Kinetics ◽  
Bainitic Transformation ◽  
Austenite Decomposition ◽  
X Ray Diffraction ◽  
Rapid Cooling ◽  
X Ray

AbstractIn-situ high-energy X-ray diffraction experiments with high temporal resolution during rapid cooling (280 °C s−1) and isothermal heat treatments (at 450 °C, 500 °C, and 550 °C for 30 minutes) were performed to study austenite decomposition in two commercial high-strength low-alloy steels. The rapid phase transformations occurring in these types of steels are investigated for the first time in-situ, aiding a detailed analysis of the austenite decomposition kinetics. For the low hardenability steel with main composition Fe-0.08C-1.7Mn-0.403Si-0.303Cr in weight percent, austenite decomposition to polygonal ferrite and bainite occurs already during the initial cooling. However, for the high hardenability steel with main composition Fe-0.08C-1.79Mn-0.182Si-0.757Cr-0.094Mo in weight percent, the austenite decomposition kinetics is retarded, chiefly by the Mo addition, and therefore mainly bainitic transformation occurs during isothermal holding; the bainitic transformation rate at the isothermal holding is clearly enhanced by lowered temperature from 550 °C to 500 °C and 450 °C. During prolonged isothermal holding, carbide formation leads to decreased austenite carbon content and promotes continued bainitic ferrite formation. Moreover, at prolonged isothermal holding at higher temperatures some degenerate pearlite form.

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