SUBMILLIMETER CONDUCTIVITY AND DIELECTRIC CONSTANT OF La1.8Sr0.2CuO4 CERAMIC

1987 ◽  
Vol 01 (03n04) ◽  
pp. 867-870 ◽  
Author(s):  
B.P. Gorshunov ◽  
Yu. G. Goncharov ◽  
G.V. Kozlov ◽  
A.M. Prokhorov ◽  
A.S. Prokhorov ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Temperature Dependence ◽  
Dielectric Function ◽  
Energy Gap ◽  
Temperature Behavior ◽  
Backward Wave Oscillator ◽  
Temperature Range ◽  
Wave Oscillator ◽  
Temperature Dependence Of Conductivity ◽  
Superconducting Energy Gap

The temperature dependence of conductivity and dielectric function of the superconducting La1.8Sr0.2CuO4 ceramic is measured using backward-wave oscillator technique at the frequency 15 cm −1 and in the temperature range 5–300K. The temperature behavior of the parameters is found to be close to the classical one at frequencies lower than superconducting energy gap.

A Tunneling Study of Superconducting YBa2 Cu3Oy By Contact Junctions At 77 K

1987 ◽  
Vol 99 ◽  
Author(s):  
H. Enomoto ◽  
K. Gotoh ◽  
K. Iida ◽  
Y. Takano ◽  
N. Mori ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Electronic Structures ◽  
Energy Gap ◽  
High Tc ◽  
Bcs Model ◽  
High Tc Superconductor ◽  
Derivative Analysis ◽  
Superconducting Energy Gap

ABSTRACTGiaever tunneling measurements have been applied to investigate the electronic structures of the high Tc superconductor YB2Cu3Oy near Tc. The superconducting energy gap of 17 meV was observed in V-dl/dv curve at 77 K. In the light of BCS model, 2Δ0Δ/kBTc was estimated as 3.3. Several dip structures were observed in the bias region up to 0.5 eV in V-dl/dV curve, using the 3rd derivative analysis. Through the temperature dependence, these structures were found to be associated with the superconductivity.

Superconductivity of very thin aluminium films

1968 ◽  
Vol 46 (9) ◽  
pp. 1129-1132 ◽  
Author(s):  
D. G. Walmsley ◽  
C. K. Campbell ◽  
R. C. Dynes
Keyword(s):  
Transition Temperature ◽  
Temperature Dependence ◽  
Crystallite Size ◽  
Energy Gap ◽  
Superconducting Energy Gap

This note presents the results of superconductive tunneling measurements which show that very thin (50–100 Å) aluminium films exhibit a unique superconducting energy gap. The temperature dependence of this gap is BCS-like, and the ratio of the gap magnitude—as extrapolated to T = 0 °K (2Δ(0))—to the observed transition temperature, Tc, remains close to the usual BCS value of 3.52 k. The effect of crystallite size on deviations from BCS results is also discussed in relation to experimental observations.

SOME PHONON EFFECTS IN SUPERCONDUCTING TUNNEL JUNCTIONS

1965 ◽  
Vol 43 (4) ◽  
pp. 557-562 ◽  
Author(s):  
J. G. Adler ◽  
J. S. Rogers ◽  
S. B. Woods
Keyword(s):  
Temperature Dependence ◽  
Phonon Spectrum ◽  
Energy Gap ◽  
Tunnel Junctions ◽  
Phonon Energy ◽  
Superconducting Tunnel Junctions ◽  
Tunnel Current ◽  
Broad Group ◽  
Superconducting Energy Gap ◽  
Phonon Structure

Tunneling measurements have been made on junctions consisting of aluminium separated from a second metal by aluminium oxide insulating layers. When the second metal was lead, tin, or indium, the effect of its phonon spectrum on the tunnel current was observed. Results with indium indicate that there is a broad group of phonons at an energy of 5 millivolts and another group at an energy of 13 millivolts in the indium phonon spectrum. The end point of the spectrum is at 14.8 ± 0.1 millivolts. Evidence is presented for a relationship between the strength of the phonon structure, the phonon energy, and the width of the superconducting energy gap from measurements on lead, tin, and indium. Measurements of the temperature dependence of the phonon structure in lead and indium are also reported.

TEMPERATURE DEPENDENCE OF GAP RELATED STRUCTURES IN YBa2Cu3O7-δ BREAK JUNCTIONS

2000 ◽  
Vol 14 (25n27) ◽  
pp. 3080-3085 ◽  
Author(s):  
F. GIUBILEO ◽  
F. BOBBA ◽  
A. M. CUCOLO ◽  
A. I. AKIMENKO
Keyword(s):  
Temperature Dependence ◽  
Energy Gap ◽  
Tunneling Current ◽  
Tunnel Barrier ◽  
Break Junction ◽  
Break Junctions ◽  
High Oxygen Pressure ◽  
Superconducting Energy Gap ◽  
Helium Gas ◽  
State Resistance

We have applied the break junction technique to highly epitaxial c-axis oriented YBaCuO thin films with T c (ρ=0)=91 K deposited on (001) SrTiO 3 or LaAlO 3 substrates by a high oxygen pressure d.c. sputtering technique. The film thickness was about 1500 Å and a photolithographic process was used to reduce to 100 μm the junction width across the fracture. By this procedure, tunable resistance break junctions with tunneling current favored along the ab-planes have been realized. The junctions were formed at low temperatures with freshly fractured surfaces and an inert tunnel barrier was created by helium gas or liquid. A good stability was obtained with the normal-state resistance R N changing about 15% in the temperature range between 4.2 K and 100 K. We have measured the temperature dependence of the conductance maxima that are related to superconducting energy gap at the Fermi level.

Temperature dependence of the superconducting energy gap of Pb

1966 ◽  
Vol 4 (1) ◽  
pp. 59-63 ◽  
Author(s):  
R.F. Gasparovic ◽  
B.N. Taylor ◽  
R.E. Eck
Keyword(s):  
Temperature Dependence ◽  
Energy Gap ◽  
Superconducting Energy Gap
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