scholarly journals Oscillating paramagnetic Meissner effect and Berezinskii–Kosterlitz–Thouless transition in Bi2Sr2CaCu2O8+δ monolayer

2022 ◽  
Author(s):  
S. Y. Wang ◽  
Yijun Yu ◽  
Jinxiang Hao ◽  
Yang Feng ◽  
Jinjiang Zhu ◽  
...  
Keyword(s):  
High Sensitivity ◽  
Interlayer Coupling ◽  
Meissner Effect ◽  
Coulomb Gas ◽  
Zero Field ◽  
2D System ◽  
Small Fields ◽  
High Transition ◽  
Bkt Transition ◽  
Scanning Squid

Abstract Monolayers of a prototypical cuprate high transition-temperature (TC) superconductor Bi2Sr2CaCu2O8+δ (Bi2212) was recently found to show TC and other electronic properties similar to those of the bulk. The robustness of superconductivity in an ideal two-dimensional (2D) system was an intriguing fact that defied the Mermin-Wagner theorem. Here, we took advantage of the high sensitivity of scanning SQUID susceptometry to image the phase stiffness throughout the phase transition of Bi2212 in the 2D limit. We found susceptibility oscillated with flux between diamagnetism and paramagnetism in a Fraunhofer-like pattern up till TC. The temperature and sample size-dependence of the modulation period agreed well with our Coulomb gas analogy of a finite 2D system based on Berezinskii–Kosterlitz–Thouless (BKT) transition. In the multilayers, the susceptibility oscillation differed in a small temperature regime below TC in consistent with a dimensional-crossover led by interlayer coupling. Serving as strong evidence of BKT transition in the bulk, there appeared a sharp superfluid density jump at zero-field and paramagnetism at small fields just below TC. These results unified the phase transitions from the monolayer Bi2212 to the bulk as BKT transition with finite interlayer coupling. This elucidating picture favored the pre-formed pairs scenario for the underdoped cuprates regardless of lattice dimensionality.

scholarly journals Electronic Optical Sky Surveys

1998 ◽  
Vol 179 ◽  
pp. 49-55
Author(s):  
T.A. McKay
Keyword(s):  
Dynamic Range ◽  
Large Fraction ◽  
High Sensitivity ◽  
High Dynamic Range ◽  
Low Noise ◽  
Computer Hardware ◽  
Optical Detectors ◽  
Small Fields ◽  
Technical Advances ◽  
High Dynamic

The introduction of of Charge Coupled Devices (CCDs) in the middle 1970s provided astronomy with nearly perfect (linear, high-sensitivity, low-noise, high dynamic-range, digital) optical detectors. Unfortunately, restrictions imposed by CCD production and cost has typically limited their use to observations of relatively small fields. Recently a combination of technical advances have made practical the application of CCDs to survey science. CCD mosaic cameras, which help overcome the size restrictions imposed by CCD manufacture, allow electronic access to a larger fraction of the available focal plane. Multi-fiber spectrographs, which couple the low-noise, high QE performance of CCDs with the ability to observe spectra for many objects at once, have improved the spectroscopic efficiency of telescopes by factors approaching half a million. An improved understanding of image distortion gives us telescopes on which we expect sub-arcsecond images a large fraction of the time. Finally, and perhaps most important, the performance of computer hardware continues to advance, to the point where analysis of multi-terabyte datasets, while still daunting, is at least conceivable.

Time Domain Zero Field NMR and NQR

1986 ◽  
Vol 41 (1-2) ◽  
pp. 440-444 ◽  
Author(s):  
A. Bielecki ◽  
D. B. Zax ◽  
A. M. Thayer ◽  
J. M. Millar ◽  
A. Pines
Keyword(s):  
Time Domain ◽  
Relaxation Times ◽  
Low Frequency ◽  
High Sensitivity ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Zero Field ◽  
Spin Lattice ◽  
Field Cycling ◽  
The Time Domain

Field cycling methods are described for the time domain measurement of nuclear quadrupolar and dipolar spectra in zero applied field. Since these techniques do not involve irradiation in zero field, they offer significant advantages in terms of resolution, sensitivity at low frequency, and the accessible range of spin lattice relaxation times. Sample data are shown which illustrate the high sensitivity and resolution attainable. Comparison is made to other field cycling methods, and an outline of basic instrumental requirements is given.

A Computer-controlled, Fully Automatic NMR/NQR Double Resonance Spectrometer

1992 ◽  
Vol 47 (1-2) ◽  
pp. 395-400 ◽  
Author(s):  
Feng Zhenye ◽  
Edwin A. C Lücken ◽  
Jacques Diolot
Keyword(s):  
High Field ◽  
Double Resonance ◽  
Low Frequency ◽  
High Sensitivity ◽  
Automatic Tuning ◽  
Zero Field ◽  
Field Region ◽  
Fully Automatic ◽  
Computer Controlled ◽  
Frequency Power

AbstractA completely automatic computer-controlled NMR/NQR double resonance spectrometer is described. It features automatic tuning of the low, variable frequency power amplifier, thus permitting untended use over long periods, with high sensitivity and signal reproducibility. The sample is transferred between the low-frequency, zero-field region and the high-field region using compressed air and the possibility of switching on a field of several tens of gauss during the transfer of the sample is also included

Transport and Meissner Effect Studies for YBa2(Cuy1−xZnx)3O7

1987 ◽  
Vol 99 ◽  
Author(s):  
S. H. Bloom ◽  
M. V. Kuric ◽  
Y. S. Yao ◽  
R. P. Guertin ◽  
D. Nichols ◽  
...  
Keyword(s):  
Electrical Resistance ◽  
Single Phase ◽  
High Sensitivity ◽  
Meissner Effect ◽  
Critical Value ◽  
Temperature Dependent ◽  
Metallic Behavior ◽  
Low Field ◽  
Normal Transition ◽  
Support Evidence

ABSTRACTSingle phase orthorhombic YBa2(Cuy1−xZnx)3O7 samples were formed for 0<x<0.16. The high T superconductivityXfor x=6 (T =90 K) is rapidly depressed with increasing x, and is quenched for x>0.08. Low field (<100 G) cooled magnetization studies show that the superconducting component decreases as x approaches the critical value for suppression of superconductivity, and this is supported by high resolution specific heat measurements in the vicinity of T. Temperature dependent electrical resistivity studies for x<0.08 show metallic behavior; for x>0.10 semiconducting behavior. The electrical resistance was studied at high quasihydrostatic pressures also, and for x=0.08 showed that T is depressed with increasing pressure: T → 0 K for P >10 GPa. This is in°contrast to YBa2(Cuy1−xZnx)3O7 where dT /dP>0. The data support evidence for the high sensitivity to chemical and ice perturbations of the physical properties of samples near the superconducting-normal transition region.

Superplastic Deformation of YBa2Cu3O7−x in a Superplastic Metal Matrix

1990 ◽  
Vol 196 ◽  
Author(s):  
J. Emilio Moreno ◽  
G. Torres-Villasefor
Keyword(s):  
Grain Boundaries ◽  
Room Temperature ◽  
Meissner Effect ◽  
Grain Boundary Sliding ◽  
New Class ◽  
Fine Grain ◽  
The Matrix ◽  
High Transition ◽  
Boundary Sliding ◽  
Zn Alloy

ABSTRACTThe new class of high-transition-temperature ceramic superconductors (e.g. Y-Ba-Cu-O) show a fine grain size polycrystalline structure, similar to that shown by the superplastic metals. The material behaves in a brittle manner with a strain to fracture below 0.5 % at room temperature. One of the reasons for this mechanical behavior is that the grain boundaries are easily separated when a stress is applied. It was found in this work that a deformation of the superconductor ceramic (scc) in superplastic metal (spin) matrix reduces the separation of the grain boundaries in such materials so that they can be deformed at room temperature. The spin matrixes used in this work were Zn-Cd, Bi-Sn and Cd-Sn. It was found that the highest the yield point of the matrix the highest the deformation induced in the scc. The Cd-Zn alloy was the most effective in avoiding the separation of the grain boundaries during the deformation of a composite formed by a cylinder of scc embedded in a spin matrix. Meissner effect was observed in the scc, after more than 160 % of plastic deformation. SEM observations show that deformation takes place by grain boundary sliding and some grain refinement was observed.

scholarly journals MAGNETOTRANSPORT IN DILUTE 2D SI-MOSFET SYSTEM

2004 ◽  
Vol 18 (27n29) ◽  
pp. 3609-3612 ◽  
Author(s):  
M. V. CHEREMISIN
Keyword(s):  
Magnetic Field ◽  
Hall Effect ◽  
Quantum Hall Effect ◽  
Quantum Hall ◽  
Field Configuration ◽  
Zero Field ◽  
Magnetic Field Configuration ◽  
Valley Splitting ◽  
2D System ◽  
Shubnikov De Haas Oscillations

The beating pattern of Shubnikov-de Haas oscillations is reproduced in crossed magnetic field configuration and in presence of zero-field valley splitting in Si -MOSFET 2D system. The features of Quantum Hall Effect in extremely dilute 2D system are discussed.

Fabrication of high Tc Superconducting Films with Diffusion Barriers

1987 ◽  
Vol 99 ◽  
Author(s):  
C. T. Ghien ◽  
Gang Xiao ◽  
M. Z. Cieplak ◽  
A. Bakhshai ◽  
A. Gavrin ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Meissner Effect ◽  
Superconducting Films ◽  
Diffusion Barriers ◽  
Buffer Layers ◽  
High Temperature Annealing ◽  
Superconducting Properties ◽  
High Tc ◽  
Effective Current ◽  
High Transition

Superconducting YBa2Cu3O; thin films have been prepared by magnetron sputtering onto [100] single crystal MgO with and without an Au buffer layer. All samples show high transition temperatures (82–87 K). The use of an Au buffer layer significantly improves the superconducting properties, particularly the Meissner effect and critical current density (3.3×106A/cm2 at 2 K and 3.5×104A/cm2 at T=77 K). The Au buffer layers remain metallic after high temperature annealing in an oxygen atmosphere, and may thus serve as effective current shunts.

Magnetic Field Sensing with Atomic Scale Defects in SiC Devices

2016 ◽  
Vol 858 ◽  
pp. 265-268 ◽  
Author(s):  
Corey J. Cochrane ◽  
Jordana Blacksberg ◽  
Patrick M. Lenahan ◽  
Mark A. Anders
Keyword(s):  
Magnetic Field ◽  
Semiconductor Industry ◽  
High Sensitivity ◽  
Field Measurements ◽  
Wide Bandgap ◽  
Atomic Scale ◽  
Zero Magnetic Field ◽  
Zero Field ◽  
Field Sensing ◽  
Magnetic Field Sensing

Silicon carbide (SiC) is well known by the semiconductor industry to have significant potential for electronics used in high temperature environments due to its wide bandgap. It is not so well-known, however, that SiC also has great potential in the area of magnetic field sensing. Using the recently demonstrated zero-field spin dependent recombination (SDR) phenomenon that naturally arises in SiC based devices, near-zero magnetic field measurements can be made with moderately high sensitivity.

Lattice statistics in a magnetic field, I. A two-dimensional super-exchange antiferromagnet

1960 ◽  
Vol 254 (1276) ◽  
pp. 66-85 ◽  
Keyword(s):  
Magnetic Field ◽  
Critical Point ◽  
Continuous Functions ◽  
Square Lattice ◽  
Lattice Statistics ◽  
Zero Field ◽  
Two Dimensional ◽  
Small Fields ◽  
Arbitrary Magnetic Field ◽  
Ising Spins

The partition function of a two-dimensional ` super-exchange ’ antiferromagnet in an arbitrary magnetic field is derived rigorously. The model is a decorated square lattice in which magnetic Ising spins on the bonds are coupled together via non-magnetic Ising spins on the vertices. By use of the decoration transformation all the thermodynamic and magnetic properties of the model are derived from Onsager’s solution for the standard square lattice in zero field. The transition temperature T t (H) is a single-valued, decreasing function of the field H . The energy and the magnetization are continuous functions of T for all magnetic fields; but the specific heat and the temperature gradient of the magnetization become infinite as — In | T — T t |. The initial ( H = 0) susceptibility is a continuous and smoothly varying function of T with a maximum 40 % above the critical point; but ∂x/∂ T becomes infinite at T = T c . In a non-vanishing field the susceptibility has a logarithmic infinity at T = T t . For small fields the behaviour near the critical point is given by X ≈ ( N μ/ kT ) {2—√2— D ( T—T c ) ln ∣ T — T c ∣ — D´H 2 ln ∣ T — T c ∣}, where D and D' are constants.

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