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

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.

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 Pulsed-laser-deposited AlN films for high-temperature SiC MIS devices

2000 ◽  
Vol 5 (S1) ◽  
pp. 591-597
Author(s):  
R. D. Vispute ◽  
A. Patel ◽  
K. Baynes ◽  
B. Ming ◽  
R. P. Sharma ◽  
...  
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Ohmic Contacts ◽  
Lattice Mismatch ◽  
Pulsed Laser ◽  
Surface Region ◽  
Degree Of Crystallinity ◽  
Ion Channeling ◽  
Cell Height ◽  
Mis Devices

We report on the fabrication of device-quality AlN heterostructures grown on SiC for high-temperature electronic devices. The AlN films were grown by pulsed laser deposition (PLD) at substrate temperatures ranging from 25 °C (room temperature) to 1000 °C. The as-grown films were investigated using x-ray diffraction, Rutherford backscattering specttroscopy, ion channeling, atomic force microscopy, and transmission electron microscopy. The AlN films grown above 700 °C were highly c-axis oriented with rocking curve FWHM of 5 to 6 arc-min. The ion channeling minimum yields near the surface region for the AlN films were ∼2 to 4%, indicating their high degree of crystallinity. TEM studies indicated that AlN films were epitaxial and single crystalline in nature with a large number of stacking faults as a results of lattice mismatch and growth induced defects. The surface roughness for the films was about 0.5 nm, which is close to the unit cell height of the AlN. Epitaxial TiN ohmic contacts were also developed on SiC, GaN, and AlN by in-situ PLD. Epitaxial TiN/AlN/SiC MIS capacitors with gate areas of 4 * 10−4 cm2 were fabricated, and high-temperature current-voltage (I-V) characteristics were studied up to 450 °C. We have measured leakage current densities of low 10−8 A/cm2 at room temperature, and have mid 10−3 A/cm2 at 450°C under a field of 2 MV/cm.

Characterization of pulsed laser deposited Zno-WS2 thin solid film lubricants

1995 ◽  
Vol 53 ◽  
pp. 558-559
Author(s):  
S. D. Walck ◽  
J. S. Zabinski ◽  
N.T. McDevitt ◽  
J. E. Bultman
Keyword(s):  
Thin Films ◽  
High Temperature ◽  
Low Temperatures ◽  
Wear Debris ◽  
Room Temperature ◽  
Pulsed Laser ◽  
Chemical Changes ◽  
Aerospace Applications ◽  
Solid Film

ZnO-WS2 is a potential high temperature solid film lubricant for aerospace applications that exhibits adaptive lubricant behavior. An adaptive lubricant undergoes phase and/or chemical changes in response to thermal, environmental, and tribological conditions; with the resulting phase or wear debris also being lubricious. Pulsed laser deposited (PLD) ZnO-WS2 thin films deposited at room temperature (RT) and wear-tested at room temperature have been shown to have coefficients of friction of 0.04 or less which are comparable to WS2 films, but have much longer wear lives. In the as-deposited state, PLD ZnO-WS2 films are amorphous, but when wear-tested, the phases WS2, WO3, and ZnWO4 are produced. Of these, WS2 is a lubricant phase at low temperatures (⪯ ~450°C) while ZnWO4 is a lubricant phase above about 600°C. The purpose of this work was to characterize the microstructural and chemical changes that occur when the RT-PLD ZnO-WS2 films are heated in air.The RT-PLD ZnO-WS2 films were deposited in a system having a base pressure of 9×l0-7 Pa with a typical pressure during deposition of 6×10-5 Pa.

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.

Pulsed-Laser-Deposited AlN Films for High-Temperature SiC MIS Devices

1999 ◽  
Vol 595 ◽  
Author(s):  
R. D. Vispute ◽  
A. Patel ◽  
K. Baynes ◽  
B. Ming ◽  
R. P. Sharma ◽  
...  
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Ohmic Contacts ◽  
Lattice Mismatch ◽  
Pulsed Laser ◽  
Surface Region ◽  
Degree Of Crystallinity ◽  
Ion Channeling ◽  
Cell Height ◽  
Mis Devices

AbstractWe report on the fabrication of device-quality AlN heterostructures grown on SiC for high-temperature electronic devices. The AlN films were grown by pulsed laser deposition (PLD) at substrate temperatures ranging from 25 °C (room temperature) to 1000 °C. The as-grown films were investigated using x-ray diffraction, Rutherford backscattering specttroscopy, ion channeling, atomic force microscopy, and transmission electron microscopy. The AlN films grown above 700 °C were highly c-axis oriented with rocking curve FWHM of 5 to 6 arc-min. The ion channeling minimum yields near the surface region for the AlN films were ∼2 to 4%, indicating their high degree of crystallinity. TEM studies indicated that AlN films were epitaxial and single crystalline in nature with a large number of stacking faults as a results of lattice mismatch and growth induced defects. The surface roughness for the films was about 0.5 nm, which is close to the unit cell height of the AlN. Epitaxial TiN ohmic contacts were also developed on SiC, GaN, and AlN by in-situ PLD. Epitaxial TiN/AlN/SiC MIS capacitors with gate areas of 4 * 10-4 cm2 were fabricated, and high-temperature current-voltage (I-V) characteristics were studied up to 450 °C. We have measured leakage current densities of low 10-8 A/cm2 at room temperature, and have mid 10-3 A/cm2 at 450°C under a field of 2 MV/cm.

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.

Sign in / Sign up

Export Citation Format

Share Document