scholarly journals Room-temperature oxygen vacancy migration induced reversible phase transformation during the anelastic deformation in CuO

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lei Li ◽  
Guoxujia Chen ◽  
He Zheng ◽  
Weiwei Meng ◽  
Shuangfeng Jia ◽  
...  
Keyword(s):  
High Temperature ◽  
Oxygen Vacancy ◽  
Room Temperature ◽  
High Temperature Superconductivity ◽  
Experimental Investigations ◽  
Solid State Chemistry ◽  
Vacancy Migration ◽  
Scientific Disciplines ◽  
Anelastic Deformation ◽  
Reversible Phase

AbstractFrom the mechanical perspectives, the influence of point defects is generally considered at high temperature, especially when the creep deformation dominates. Here, we show the stress-induced reversible oxygen vacancy migration in CuO nanowires at room temperature, causing the unanticipated anelastic deformation. The anelastic strain is associated with the nucleation of oxygen-deficient CuOx phase, which gradually transforms back to CuO after stress releasing, leading to the gradual recovery of the nanowire shape. Detailed analysis reveals an oxygen deficient metastable CuOx phase that has been overlooked in the literatures. Both theoretical and experimental investigations faithfully predict the oxygen vacancy diffusion pathways in CuO. Our finding facilitates a better understanding of the complicated mechanical behaviors in materials, which could also be relevant across multiple scientific disciplines, such as high-temperature superconductivity and solid-state chemistry in Cu-O compounds, etc.

Controlling the Reactivity of C60: A Theoretical Analysis of the Electronic States Modulated by Substitutional Chemistry

1994 ◽  
Vol 359 ◽  
Author(s):  
S.-H. Wang ◽  
M. Kashani ◽  
S. Jansen
Keyword(s):  
High Temperature ◽  
Theoretical Analysis ◽  
High Temperature Superconductivity ◽  
Electronic States ◽  
Experimental Investigations ◽  
Cluster Stability ◽  
Simple Substitution ◽  
Doped Materials ◽  
Multiple Species

ABSTRACTThe availability of large amounts of Buckminsterfullerene has allowed a plethora of experimental investigations on fullerenes. The chemical and physical studies have focussed on synthesis, isomerism, magnetism, spectroscopy and high temperature superconductivity in doped materials. The chemical reactivities of fullerenes have been defined and most of the studies are dominated by C60 isomers. Some of the observed activities of fullerenes parlled those of alkeies. In our previous studies, the reactivity of the 6-6' bond with respect to eco- addition was described. Current studies have exploited the olefinic nature of the 6-6' bond and analyzed the effect of the addition on cluster stability and frontier character. In this work, we describe the mechanisms of simple substitution and analyze stability and orbital effects for the addition chemistry of C60 with multiple species. Evolving changes in orbital frontier character are analyzed with respect to site directed chemistry exhibited by C60.

scholarly journals ELECTRON–PHONON INTERACTIONS CAUSE HTSC

2001 ◽  
Vol 15 (24n25) ◽  
pp. 3153-3155 ◽  
Author(s):  
J. C. PHILLIPS
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
High Temperature Superconductivity ◽  
Temperature Conductivity ◽  
Room Temperature Conductivity ◽  
Light Pulses ◽  
Pressure Changes

What is the microscopic interaction responsible for high temperature superconductivity (HTSC)? Here data on temporal relaxation of T c and the room temperature conductivity in YBa2Cu3O 6+x after abrupt alteration by light pulses or pressure changes are analyzed. The analysis proves, independently of microscopic details, that only electron–phonon interactions can cause HTSC in the cuprates; all other dynamical interactions are excluded by experiment.

scholarly journals Application of Water Fracturing in Geothermal Energy Mining: Insights from Experimental Investigations

Energies ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 2138 ◽  
Author(s):  
Zhihong Lei ◽  
Yanjun Zhang ◽  
Zhongjun Hu ◽  
Liangzhen Li ◽  
Senqi Zhang ◽  
...  
Keyword(s):  
High Temperature ◽  
Hydraulic Fracturing ◽  
Room Temperature ◽  
Injection Rate ◽  
Rock Properties ◽  
Experimental Investigations ◽  
Residual Pressure ◽  
Crack Network ◽  
High Injection ◽  
Injection Rates

Currently, water fracturing under deep geothermal conditions remains poorly understood because the reservoir rocks are usually high-strength crystalline rocks characterized by high temperatures. The aim of this study is to investigate the effects of rock properties, injection rates, and temperatures on hydraulic fracturing behavior and the induced crack characteristics through experimental investigations. A series of hydraulic fracturing experiments was conducted on two Indosinian granite types to investigate the differences in hydraulic fracturing behavior caused by rock properties. Among others, six samples were tested under a room-temperature condition at different injection rates from 1 to 30 mL/min to clarify the effect of the injection rate and three samples were tested under a high-temperature condition (150 °C) to simulate specific geothermal environments. The results indicated that granites with different rock properties have different injection rate thresholds. When the injection rate is below the threshold, the injection pressure finally reached a constant value without fracturing. For rocks with the same properties, the temperature effect can lead to a high injection rate threshold due to the occurrence of thermally-induced cracks. The number of acoustic emission events recorded during the room-temperature experiments increased linearly with increasing injection rate, while high-temperature tests increased sharply. The investigation results imply that a complex hydraulically-induced crack network is expected to be achieved in geothermal reservoirs by a high injection rate or high temperature differences (between injected fluid and rock). Additionally, the characteristics of the hydraulically-induced cracks were investigated by cutting through the sample blocks and measuring the residual pressure. The results indicated that the induced crack aperture can maintain a fluid conductivity of 0.1–0.8 mm/s at a closure pressure of 12 MPa.

Induction of high-temperature superconductivity in pulsed laser ablated La2CuO4thin films by room temperature chemical oxidation

1997 ◽  
Vol 9 (10) ◽  
pp. 823-826 ◽  
Author(s):  
Simon T. Lees ◽  
Peter P. Edwards ◽  
Ian Gameson ◽  
Martin O. Jones ◽  
Marcin Slaski ◽  
...  
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
High Temperature Superconductivity ◽  
Pulsed Laser ◽  
Chemical Oxidation

Itinerant Vibrons and High-Temperature Superconductivity*

2000 ◽  
Vol 658 ◽  
Author(s):  
John B. Goodenough
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
High Temperature Superconductivity ◽  
Phase Segregation ◽  
Optical Mode ◽  
Temperature Changes ◽  
Critical Composition ◽  
Underdoped Region ◽  
Small Polarons ◽  
Electronic Behavior

ABSTRACTThe La2−xSrxCuO4 phase diagram is interpreted within the framework of a transition from localized to itinerant electronic behavior. In the underdoped region 0 < x < 0.1, holes in the x2 – y2 band are not small polarons; each occupies a mobile correlation bag of 5 to 6 copper centers at temperatures T > TF, a spinodal phase segregation into the parent antiferromagnetic phase and a polaron liquid is accomplished below TF by cooperative oxygen displacements. In the overdoped compositions > x > 0.25, holes are excluded from strong-correlation fluctuations within a Fermi liquid. In the intermediate range 0.1 < x < 0.25, the polaron liquid formed below room temperature changes character with increasing x and decreasing T. In the polaron liquid, mobile two-hole bags of four copper centers order with decreasing temperature into alternate CuO-Cu rows of a superconductive CuO2 sheet at a critical composition xc ≍ 1/6. It is argued that hybridization of itinerant electrons with optical-mode phonons propagating along the Cu-O-Cu rows produces heavy electrons responsible for high-temperature superconductivity.

High-temperature superconductivity in tetragonal perovskite structures: Is oxygen-vacancy order important?

1988 ◽  
Vol 60 (14) ◽  
pp. 1446-1449 ◽  
Author(s):  
Gang Xiao ◽  
M. Z. Cieplak ◽  
A. Gavrin ◽  
F. H. Streitz ◽  
A. Bakhshai ◽  
...  
Keyword(s):  
High Temperature ◽  
Oxygen Vacancy ◽  
High Temperature Superconductivity

scholarly journals The Needle in the Haystack for Theory of High Temperature Superconductivity: Negative Nuclear Magnetic Moments

2018 ◽  
Author(s):  
Reginald Little
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Cooper Pair ◽  
High Temperature Superconductivity ◽  
Magnetic Moments ◽  
High Energy ◽  
Cooper Pairs ◽  
Nuclear Magnetic Moments ◽  
Relativistic Scattering ◽  
Nuclear Magnetic

This work outlines a theory for explaining high temperature superconductivity on the basis of relativistic scattering of Cooper pairs via beyond room temperature conditions causing high energy relativistic scattering of Cooper pairs with nuclei having positive and negative nuclear magnetic moments for fractionally reversibly fissing and fusing the nuclei for manifesting in the electronic lattice for altered quantum fields for more tightly binding the Cooper pair beyond the conventional critical temperature 40K limit for superconductivity beyond room temperature.

scholarly journals The Needle in the Haystack for Theory of High Temperature Superconductivity: Negative Nuclear Magnetic Moments

2018 ◽  
Author(s):  
Reginald Little
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Cooper Pair ◽  
High Temperature Superconductivity ◽  
Magnetic Moments ◽  
High Energy ◽  
Cooper Pairs ◽  
Nuclear Magnetic Moments ◽  
Relativistic Scattering ◽  
Nuclear Magnetic

This work outlines a theory for explaining high temperature superconductivity on the basis of relativistic scattering of Cooper pairs via beyond room temperature conditions causing high energy relativistic scattering of Cooper pairs with nuclei having positive and negative nuclear magnetic moments for fractionally reversibly fissing and fusing the nuclei for manifesting in the electronic lattice for altered quantum fields for more tightly binding the Cooper pair beyond the conventional critical temperature 40K limit for superconductivity beyond room temperature.

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