scholarly journals The superconducting transition and mixed state of YBa2Cu3O6.95: an undergraduate experiment

2021 ◽  
Author(s):  
Zhongda Huang ◽  
Yihang Tong ◽  
Jake Bobowski
Keyword(s):  
Magnetic Susceptibility ◽  
Single Crystal ◽  
Mixed State ◽  
High Temperature Superconductors ◽  
Polycrystalline Sample ◽  
Single Crystal Sample ◽  
Base Temperature ◽  
Superconducting Transition ◽  
Temperature Drift ◽  
Crystal Sample

Abstract We describe a simple AC susceptometer built in-house that can be used to make high-resolution measurements of the magnetic susceptibility of high-temperature superconductors in an undergraduate physics lab. Our system, cooled using liquid nitrogen, can reach a base temperature of 77 K. Our apparatus does not require gas handling systems or PID temperature controllers. Instead, it makes use of a thermal circuit that is designed to allow the sample to cool on a time scale that is suitable for an undergraduate lab. Furthermore, the temperature drift rate at the superconducting transition temperature T c is low enough to allow for precise measurements of the complex magnetic susceptibility through T c, even for single-crystal samples with exceedingly sharp superconducting transitions. Using an electromagnet, we were able to apply static magnetic fields up to 63 mT at the sample site. By measuring the change in susceptibility as a function of the strength of an applied of static magnetic field, we were able to estimate the lower critical field H c1 of a single-crystal sample of optimally-doped YBa2Cu3O6.95 at 77 K. We also investigated the mixed state of a sintered polycrystalline sample of YBa2Cu3O6+y .

Stability of High-Spin State of Iron in β-NaFeO2

2020 ◽  
Vol 855 ◽  
pp. 177-182
Author(s):  
Mochammad Yan Pandu Akbar ◽  
Rieko Ishii ◽  
Agustinus Agung Nugroho
Keyword(s):  
Single Crystal ◽  
High Spin ◽  
Spin State ◽  
High Spin State ◽  
Polycrystalline Sample ◽  
Single Crystal Sample ◽  
Structural Refinement ◽  
Crystal Sample ◽  
The Stability ◽  
Crystal Volume

We investigated the stability of the high-spin state of the iron β-NaFeO2 based on the structural refinement. The oxidation of the Fe2+ ion in the as-synthesized sample is evidenced by its green color. Due to its sensitivity in air and CO2, this compound will decompose into a reddish Fe3+ state. The smaller crystal volume of the decomposed compound is mainly related to the shorter ionic radius of the high-spin state Fe3+ and this result will be compared to the single crystal sample. In contrast to the polycrystalline sample, the decomposition single crystal sample only taking place on the surface of the as-grown crystal.

scholarly journals Stability and equation of state of face-centered cubic and hexagonal close packed phases of argon under pressure

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Agnès Dewaele ◽  
Angelika D. Rosa ◽  
Nicolas Guignot ◽  
Denis Andrault ◽  
João Elias F. S. Rodrigues ◽  
...  
Keyword(s):  
Equation Of State ◽  
Single Crystal ◽  
Single Crystal Sample ◽  
Moderate Pressure ◽  
Face Centered Cubic ◽  
Experimental Conditions ◽  
Crystal Sample ◽  
Hexagonal Close Packed ◽  
Face Centered ◽  
Fcc Phase

AbstractThe compression of argon is measured between 10 K and 296 K up to 20 GPa and and up to 114 GPa at 296 K in diamond anvil cells. Three samples conditioning are used: (1) single crystal sample directly compressed between the anvils, (2) powder sample directly compressed between the anvils, (3) single crystal sample compressed in a pressure medium. A partial transformation of the face-centered cubic (fcc) phase to a hexagonal close-packed (hcp) structure is observed above 4.2–13 GPa. Hcp phase forms through stacking faults in fcc-Ar and its amount depends on pressurizing conditions and starting fcc-Ar microstructure. The quasi-hydrostatic equation of state of the fcc phase is well described by a quasi-harmonic Mie–Grüneisen–Debye formalism, with the following 0 K parameters for Rydberg-Vinet equation: $$V_0$$ V 0 = 38.0 Å$$^3$$ 3 /at, $$K_0$$ K 0 = 2.65 GPa, $$K'_0$$ K 0 ′ = 7.423. Under the current experimental conditions, non-hydrostaticity affects measured P–V points mostly at moderate pressure ($$\le$$ ≤ 20 GPa).

Extending the temperature sensing range using Eu3+ luminescence up to 865 K in a single crystal of EuPO4

2019 ◽  
Vol 21 (29) ◽  
pp. 16329-16336 ◽  
Author(s):  
Suchinder K. Sharma ◽  
Thomas Köhler ◽  
Jan Beyer ◽  
Margret Fuchs ◽  
Richard Gloaguen ◽  
...  
Keyword(s):  
Single Crystal ◽  
Temperature Sensing ◽  
Single Crystal Sample ◽  
Coupling Scheme ◽  
Excitation Wavelength ◽  
Crystal Sample ◽  
Sensing Range

Extending the temperature sensing range up to 865 K using an appropriate choice of excitation wavelength and coupling scheme in a single crystal sample of EuPO4.

Origin of Paramagnetic Defect in Single Crystal and Ceramic B4C

1987 ◽  
Vol 97 ◽  
Author(s):  
E. L. Venturini ◽  
D. Emin ◽  
T. L. Aselage
Keyword(s):  
Single Crystal ◽  
Angular Dependence ◽  
Esr Spectra ◽  
Single Crystal Sample ◽  
Paramagnetic Defect ◽  
Crystal Sample ◽  
Spin Resonance ◽  
Integrated Intensity ◽  
Increasing Temperature ◽  
Positively Charged

ABSTRACTWe compare electron spin resonance (ESR) spectra of B4C samples made by three methods. The samples are 1) two ceramics made by hot-pressing boron and carbon powders, 2) a polycrystal made by carbothermic reduction, and 3) a single crystal grown from a palladium metal melt. All samples show remarkably similar spectra between 2 and 100 K. In particular, all samples show a single Lorentzian absorption, a linewidth that decreases with increasing temperature, and an inverse temperature dependence of the integrated intensity. The integrated intensity of the paramagnetic spin signal corresponds to a density of 2×1019/cm2 localized spins. Having a single crystal sample enables us to meaningfully measure the angular dependence of the ESR linewidth. This angular dependence is consistent with the paramagetic centers being unpaired electrons centered on the central carbon atoms of positively charged C-C-C intericosahedral chains. These chains appear to replace 0.5 % of the positively charged C-B-C intericosahedral chains which occur in B4C.

A Fundamental Model of Aluminum Single Crystal Behavior with Physical Description of Kinematic Work Hardening

2007 ◽  
Vol 550 ◽  
pp. 577-582 ◽  
Author(s):  
Afaf Saai ◽  
Laurent Tabourot ◽  
Christophe Déprés ◽  
Herve Louche
Keyword(s):  
Single Crystal ◽  
Work Hardening ◽  
Single Crystal Sample ◽  
Large Strains ◽  
Shear Stresses ◽  
State Variables ◽  
Aluminum Single Crystal ◽  
Crystal Sample ◽  
Hardening Mechanism ◽  
Fundamental Model

In this paper, we present a fundamental model of FCC single crystal behaviour at room temperature: this model includes kinematic work hardening derived from the elementary description of the collective dislocations density evolution during cyclic loading. This kinematic work hardening is then coupled with the isotropic work hardening mechanism. Using this original model, a simulation of a tensile test on a single crystal sample is carried out in the case of an initial crystal orientation that promotes single glide even at rather large strains. The evolution of resolved shear stresses on the primary and secondary slip systems are interpreted by means of the interaction between the evolution of isotropic and kinematic work hardening variables. The evolution of the model state-variables including applied resolved shear strain, dislocation densities, and critical shear stresses are represented as functions of the evolution of crystalline orientation during plastic deformation.

Atomic Registry at the Pt-Si Interface Studied by Transmission Channeling RBS

1986 ◽  
Vol 77 ◽  
Author(s):  
John R. Abelson ◽  
Thomas W. Sigmon
Keyword(s):  
Single Crystal ◽  
Volume Effect ◽  
Single Crystal Sample ◽  
Single Crystal Substrate ◽  
Crystal Sample ◽  
Internal Interface ◽  
Ion Channeling ◽  
Rutherford Scattering ◽  
Crystal Substrate ◽  
Cleaning Procedures

ABSTRACTTransmission channeling Rutherford scattering of MeV ions is one of the only techniques which can probe the atomic registry at a “buried” internal interface between a thin film and single-crystal substrate. Interfacial intermixing, dislocations, and reconstruction can be observed at concentrations above ∼ 3×1015 atoms/cm. The physical basis for this measurement is the “flux-peaking” effect, which is well known in conventional ion channeling as a method to determine the lattice location of dilute impurities. Transmission channeling is conceptually similar, but the scattering arises from the interface at the exit side of a thin single crystal sample rather than from a volume effect.In this work, we apply transmission channeling to measure the low temperature intermixing between Pt and Si. In a previous study, we suggested that a disordered interface forms prior to crystalline suicide formation. The present results are a quantitative measurement of the area density of Si which intermixes with Pt at 150°C. Experiments are performed using 80A Pt layers e-béam deposited onto 1–2μm thick single crystals of Si(100) and (111) following various interfacial cleaning procedures. We find that >1×1016 Si atoms/cm2 are displaced from their lattice sites after Pt deposition, increasing to ∼2×1016/cm2 upon annealing to 150°C. The room temperature intermixing of >6 monolayers of Si is large, but not inconsistent with existing studies of the Pt - Si reaction. The transmission channeling measurement includes any Si segregated at grain boundaries or the free surface as well as the interface. No systematic differences are observed as a function of substrate orientation or cleaning procedure.

The effect of diffraction by the diamonds of a diamond-anvil cell on single-crystal sample intensities

1990 ◽  
Vol 23 (5) ◽  
pp. 392-396 ◽  
Author(s):  
J. S. Loveday ◽  
M. I. McMahon ◽  
R. J. Nelmes
Keyword(s):  
High Pressure ◽  
Single Crystal ◽  
Diamond Anvil Cell ◽  
Structural Information ◽  
Wavelength Dependence ◽  
Single Crystal Sample ◽  
Data Sets ◽  
Crystal Sample ◽  
Diamond Anvil ◽  
Integrated Intensities

The integrated intensities measured in X-ray single-crystal high-pressure structural studies using a diamond-anvil cell are shown to be reduced substantially when the diamonds diffract at the same setting as the sample – by as much as 50% in some cases. The pressure and wavelength dependence of this process have been studied and also the effect of changing the beam divergence by the use of a synchrotron beam. The consequences for the accuracy of structural information derived from data sets collected at high pressure are considered and a data-collection strategy for detecting and avoiding the effects of diamond diffraction is proposed.

Magnetoacoustic oscillations and the stress dependence of the Fermi surface of tungsten

1976 ◽  
Vol 54 (12) ◽  
pp. 1234-1239 ◽  
Author(s):  
D. J. Stanley ◽  
J. M. Perz ◽  
H. -P. Au
Keyword(s):  
Fermi Surface ◽  
Elastic Constant ◽  
Single Crystal ◽  
Cross Sections ◽  
Single Crystal Sample ◽  
Stress Dependence ◽  
Crystal Sample ◽  
Quantum Oscillations ◽  
Strain Dependence ◽  
First Time

The absolute amplitudes of quantum oscillations in magnetostriction and the elastic constant, c11, have been measured simultaneously, for the first time, in a single crystal sample of tungsten. They are combined to give the strain dependence of the Fermi surface cross sections normal to [100] of the ball and ellipsoid surfaces. Comparison with values measured in another type of uniaxial experiment and with pressure derivatives indicates that the results are consistent, and that the method is feasible, although less convenient than other possible measurements giving the same information.

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