The effect of boundary conditions on the superconducting transition critical temperature in superlattices

2001 ◽  
Vol 46 (2) ◽  
pp. 270-271
Author(s):  
I. N. Askerzade
Keyword(s):  
Critical Temperature ◽  
Boundary Conditions ◽  
Superconducting Transition

Scaling of Resistivities in MgB2

2006 ◽  
Vol 47 ◽  
pp. 113-117
Author(s):  
Petr Vašek
Keyword(s):  
Magnetic Field ◽  
Thin Films ◽  
Critical Temperature ◽  
External Magnetic Field ◽  
Transport Current ◽  
Zero Magnetic Field ◽  
Superconducting Transition ◽  
Hall Voltage ◽  
Transition Range ◽  
Width Of Superconducting Transition

Longitudinal and transverse voltages have been measured on thin films of MgB2 with different width of superconducting transition range. The study has been performed in zero and nonzero external magnetic fields. The non-zero transverse voltage has been observed in close vicinity of the critical temperature in zero external magnetic field while far enough from Tc this voltage has been zero. In magnetic field it merges into transverse voltage which is an even function with respect to the direction of the field. Usual Hall voltage starts to appear with increasing magnetic field. At the highest field the even voltage disappears and only the Hall voltage is measurable i.e. the transverse even voltage is suppressed with increasing magnetic field and increasing transport current as well. New scaling between transverse and longitudinal resistivities has been observed in the form ρxy~dρxx/dT . This correlation is valid not only in the zero magnetic field but also in nonzero magnetic field where transverse even voltage can be detected. Several models trying to explain observed results are discussed. The most promising seems to be guided motion of the vortices.

AN ISING INTERFACE BETWEEN TWO WALLS: COMPETITION BETWEEN TWO TENDENCIES

1996 ◽  
Vol 08 (05) ◽  
pp. 669-687 ◽  
Author(s):  
J.L. LEBOWITZ ◽  
A.E. MAZEL ◽  
YU. M. SUHOV
Keyword(s):  
Boundary Condition ◽  
Critical Temperature ◽  
Ising Model ◽  
Boundary Conditions ◽  
Spin System ◽  
Middle Layer ◽  
Bottom Layer ◽  
Ising Spin ◽  
Ising Spin System

We consider a ferromagnetic Ising spin system, consisting of m+1, d-dimensional, layers with “–” boundary condition on the bottom layer and “+” on the top layer. When β is larger than βcr, the inverse critical temperature for the d-dimensional Ising model, the interface generated by the boundary conditions is expected to be halfway between bottom and top, for m odd, and just above or below the middle layer, for m even (each possibility with probability [Formula: see text]). In this paper, we prove the above assertion under the condition that β≥const . m and partly for β>βcr.

MAGNETIC, ELECTRIC AND EQUILIBRIUM PROPERTIES OF YBa2Cu3-x(PO4)xO7-δ HIGH TEMPERATURE SUPERCONDUCTING SYSTEM

2009 ◽  
Vol 23 (06) ◽  
pp. 807-813
Author(s):  
M. A. URIBE LAVERDE ◽  
D. A. LANDÍNEZ TÉLLEZ ◽  
J. ROA-ROJAS
Keyword(s):  
Critical Temperature ◽  
Linear Response ◽  
Carrier Density ◽  
Transfer Model ◽  
Superconducting Transition ◽  
Phosphate Content ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Capacity Measurements ◽  
Charge Transfer Model

The new YBa 2 Cu 3-x( PO 4)x O 7-δ (x = 0; 0.03; 0.06; 0.09; 0.12) superconducting material was synthesized by the standard solid state reaction recipe. X-ray diffraction results show the effective substitution of copper for phosphate and also show no evidence of any impurity related with phosphate content. Resistivity, DC magnetization and heat capacity measurements reveal a superconducting transition for all samples with a maximum critical temperature up to 97 K, corresponding to the x = 0.03 sample. For higher doping values, the critical temperature decreases in an approximately linear response. In agreement with the charge transfer model, the critical temperature decreases with the carrier density. For x = 0.03, the critical temperature shows a rise up due to an approximation to the optimum density which separates over-doped and under-doped regimes. The maximum critical temperature achieved is one of the highest ever seen for the 123-type superconductors.

scholarly journals Response of Critical Temperature of the Superconducting Transition and Energy Gaps of MgB$_2$ to the Hydrostatic Compression

2017 ◽  
Vol 39 (6) ◽  
pp. 719-731
Author(s):  
O. I. D’yachenko ◽  
◽  
V. Yu. Tarenkov ◽  
V. V. Kononenko ◽  
◽  
...  
Keyword(s):  
Critical Temperature ◽  
Hydrostatic Compression ◽  
Superconducting Transition ◽  
Energy Gaps

scholarly journals Квантовый размерный эффект в сверхпроводящих пленках алюминия

2019 ◽  
Vol 61 (9) ◽  
pp. 1609
Author(s):  
К.Ю. Арутюнов ◽  
Е.А. Седов ◽  
И.А. Голоколенов ◽  
В.В. Завьялов ◽  
Г. Константинидис ◽  
...  
Keyword(s):  
Critical Temperature ◽  
Superconducting Transition ◽  
Phonon Interaction ◽  
High Quality ◽  
Aluminum Films ◽  
Noticeable Increase ◽  
Electron Phonon Interaction ◽  
Quantum Size ◽  
Gaas Substrates ◽  
Density Of Electron States

High-quality aluminum films on GaAs substrates were experimentally studied. A noticeable increase in the critical temperature of the superconducting transition with a decrease in the film thickness was found. The effect is interpreted as manifestation of the quantum size effect, which affects both the density of electron states and the electron-phonon interaction.

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