Records |
Author |
Esparza, D.A.; D'Ovidio, C.A.; Guimpel, J.; Osquiguil, E.; Civale, L.; de la Cruz, F. |
Title |
The granular nature of bulk superconductivity at 40K in La1.8Sr0.2CuO4 |
Type |
Journal Article |
Year  |
1987 |
Publication |
Solid State Communications |
Abbreviated Journal |
Solid State Commun. |
Volume |
63 |
Issue |
2 |
Pages |
137-140 |
Keywords |
CERAMIC MATERIALS; GRANULAR MATERIALS; LANTHANUM COMPOUNDS – Electric Conductivity; CRITICAL FIELDS; HIGH TEMPERATURE SUPERCONDUCTOR; MAGNETIC FLUX EXPULSION; TEMPERATURE DEPENDENCE; SUPERCONDUCTING MATERIALS |
Abstract |
We have measured the electrical resistivity, magnetic flux expulsion and critical fields of the new high temperature superconductor La1.8Sr0.2CuO4 after different heat treatments. Our data show that the complete flux expulsion in these samples is consistent with the presence of shielding currents induced in multiple connected structures. The magnetization measurements indicate that the lowest field where flux penetrates into the sample should not be taken to be the bulk Hcl. It is shown that the absolute value of the electrical resistivity and its temperature dependence are not correlated with the superconducting critical field and temperature. We discuss the behaviour of the superconducting parameters and their relation with the electrical resistivity. |
Address |
Basic Research Department, Centro At |
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00381098 (ISSN) |
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Export Date: 17 April 2009; Source: Scopus; CODEN: SSCOA; Language of Original Document: English; Correspondence Address: Esparza, D.A.; Applied Research Department; Centro At |
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no |
Call Number |
BT @ osquigui @ |
Serial |
418 |
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Author |
Núñez Regueiro, M.; Esquinazi, P.; Izbizky, M.A.; Durán, C.; Castello, D.; Luzuriaga, J. |
Title |
Tunneling systems in high temperature superconductors |
Type |
Journal Article |
Year  |
1988 |
Publication |
Annales de Physique |
Abbreviated Journal |
Ann. Phys. Fr. |
Volume |
13 |
Issue |
5 |
Pages |
401-406 |
Keywords |
acoustic wave absorption; acoustic wave velocity; barium compounds; high temperature superconductors; lanthanum compounds; rare earth compounds; strontium compounds; superconductive tunnelling; thermal conductivity of solids; tunnelling systems; high temperature superconductors; thermal conductivity; sound attenuation; sound velocity; model; low temperature specific heat; La Sr Cu O |
Abstract |
We have measured the thermal conductivity, sound attenuation and relative variation of sound velocity of compounds of the La-Sr-Cu-O and RBa2Cu3O7 families, where R is a rare-earth. We have found that all these properties can be quantitatively correlated within a tunneling system model similar to that used in amorphous materials. This interpretation would naturally explain the anomalous linear term of the low temperature specific heat observed in these materials. |
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ISSN |
0003-4169 |
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ISI:A1988Q715000009 |
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no |
Call Number |
BT @ hernan @ |
Serial |
264 |
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Author |
Osquiguil, E.; Decca, R.; Nieva, G.; Civale, L.; de la Cruz, F. |
Title |
La1.80 Sr0.20 CuO4-delta a clean limit superconductor |
Type |
Journal Article |
Year  |
1988 |
Publication |
Solid State Communications |
Abbreviated Journal |
Solid State Commun. |
Volume |
65 |
Issue |
6 |
Pages |
491-494 |
Keywords |
CERAMIC MATERIALS; LANTHANUM COMPOUNDS – Electric Conductivity; CERAMIC SUPERCONDUCTORS; CLEAN LIMIT SUPERCONDUCTOR; HIGH-TEMPERATURE SUPERCONDUCTORS; OXYGEN CONCENTRATION; SUPERCONDUCTING MATERIALS |
Abstract |
The electrical resistivity of the superconductor La1.80Sr0.20Cu04-? has been measured in a wide range of temperatures as a function of oxygen and vacuum heat treatments. The resistivity changes reversibly orders of magnitude with oxygen concentration. There is no sign of saturation at high temperatures, even for samples where the resistivity is increased by heat treatment in vacuum. Using the experimental data and general arguments it is concluded that the ceramic superconductors are high ? materials in the clean limit. |
Address |
Instituto Balseiro 8400 Bariloche, R.N., Argentina# # Comisi |
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00381098 (ISSN) |
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Export Date: 17 April 2009; Source: Scopus; CODEN: SSCOA; Language of Original Document: English; Correspondence Address: Osquiguil, E. |
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no |
Call Number |
BT @ osquigui @ |
Serial |
416 |
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Author |
Decca, R.; Osquiguil, E.; de la Cruz, F.; D'Ovidio, C.; Malachevski, M.T.; Esparza, D. |
Title |
Non linear temperature dependence of the resistivity of LaSrCuO: Effects of Sr content |
Type |
Journal Article |
Year  |
1989 |
Publication |
Solid State Communications |
Abbreviated Journal |
Solid State Commun. |
Volume |
69 |
Issue |
4 |
Pages |
355-357 |
Keywords |
Ceramic Materials; Lanthanum Compounds--Electric Conductivity; Superconductivity; Ceramic Superconductors; Superconducting Materials |
Abstract |
The linear temperature dependence of the electrical resistivity has been taken to be one of the characteristic features of the ceramic superconductors. Measurements of the electrical resistance of the LaSrCuO system in a wide temperature range show that the previous statement is only an approximation valid for some values of the Sr concentration. |
Address |
Applied Research Department, Centro At'omico Bariloche |
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00381098 (ISSN) |
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Cited By (since 1996): 2; Export Date: 17 April 2009; Source: Scopus; CODEN: SSCOA; Language of Original Document: English; Correspondence Address: Decca, R.; Basic Research Department; Centro At |
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no |
Call Number |
BT @ osquigui @ |
Serial |
414 |
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Author |
Rodriguez, E.; Luzuriaga, J.; Núñez Regueiro, M.; Fainstein, C. |
Title |
Low temperature internal friction peak in high Tc superconductors |
Type |
Journal Article |
Year  |
1991 |
Publication |
Solid State Communications |
Abbreviated Journal |
Solid State Commun. |
Volume |
77 |
Issue |
10 |
Pages |
777-780 |
Keywords |
Ceramic Materials; Oxides – Acoustic Properties; Yttrium Compounds – Acoustic Properties; Acoustic Variables Measurement; Attenuation Peak; Calcium Compounds; Low Temperature Internal Friction Peak; Strontium Compounds; Thermally Activated Relaxation Behavior; High Temperature Superconductors |
Abstract |
We measure the internal friction Q-1 in YBa2Cu3O7-x and Bi2Sr2CaCu2O8+x samples. At temperatures near 35 K for KHz frequencies we observe an attenuation peak. In the case of YBa2Cu3O7-x, assuming a thermally activated relaxation behaviour, we are able to show that it corresponds to the same process as other peaks observed at higher frequencies. For Bi2Sr2CaCu2O8+x this is not the case, and the origin of the peak, found in all the measured samples, remains unknown. |
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0038-1098 |
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Notes |
ISI:A1991FA71400006 |
Approved |
no |
Call Number |
BT @ hernan @ |
Serial |
256 |
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Author |
Dhalle, M.; Boon, W.; Osquiguil, E.; Van Haesendonck, C.; Bruynseraede, Y.; Kwarciak, J.; Van Der Biest, O. |
Title |
Correlation between critical current and resistivity in YBa2Cu3O7 |
Type |
Journal Article |
Year  |
1991 |
Publication |
Physica C: Superconductivity and its applications |
Abbreviated Journal |
Phys C Supercond Appl |
Volume |
185-189 |
Issue |
PART 4 |
Pages |
2447-2448 |
Keywords |
Ceramic Materials; Yttrium Compounds--Electric Conductivity; Critical Currents; Oxide Superconductors; Yttrium Barium Copper Oxides; High Temperature Superconductors |
Abstract |
Critical current versus temperature measurements were carried out in ceramic YBa2Cu3O7 samples. The samples were all prepared using the same sintering procedure, but starting from powders obtained by different wet and dry methods. All samples showed a linear Jc vs. T behaviour, typical of Josephson weak-link coupling, with a slope that depends on the preparation method. Using the Ambegaokar-Baratoff relation for Jc, the difference in slopes can be attributed to a change in the characteristic value of the junction resistance. This value turns out to be clearly correlated with the resistivity in the normal state. |
Address |
Department of Metallurgy and Materials Engineering, Katholieke Universiteit Leuven, de Croylaan 2, B-3001 Leuven, Belgium |
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09214534 (ISSN) |
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Export Date: 17 April 2009; Source: Scopus; CODEN: PHYCE; Language of Original Document: English; Correspondence Address: Dhalle, M.; Laboratorium voor Vaste Stof-Fysika en Magnetisme; Katholieke Universiteit Leuven; Celestijnenlaan 200D B-3001 Leuven, Belgium |
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no |
Call Number |
BT @ osquigui @ |
Serial |
410 |
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Author |
Vanacken, J.; Osquiguil, E.; Bruynseraede, Y. |
Title |
Irreversibility line and critical currents in oxygen deficient YBa2Cu3Ox ceramics |
Type |
Journal Article |
Year  |
1991 |
Publication |
Physica C: Superconductivity and its applications |
Abbreviated Journal |
Phys C Supercond Appl |
Volume |
183 |
Issue |
1-3 |
Pages |
163-166 |
Keywords |
Ceramic Materials; Crystals; Oxygen; Yttrium Compounds; Critical Currents; Oxide Superconductors; Yttrium Barium Copper Oxides; High Temperature Superconductors |
Abstract |
The influence of oxygen concentration on the irreversibility line and critical current of polycrystalline YBa2Cu3Ox was determined using field and zero-field cooled magnetic measurements and magnetic hysteresis data. Although the field dependence of Tirr(H) is unchanged, the irreversibility line shifts to lower temperatures for decreasing oxygen content and the critical current density is strongly reduced. |
Address |
Laboratorium voor Vaste Stof-Fysika en Magnetisme, Katholieke Universiteit Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium |
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09214534 (ISSN) |
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Cited By (since 1996): 8; Export Date: 17 April 2009; Source: Scopus; CODEN: PHYCE; Language of Original Document: English; Correspondence Address: Vanacken, J.; Laboratorium voor Vaste Stof-Fysika en Magnetisme; Katholieke Universiteit Leuven; Celestijnenlaan 200D 3001 Leuven, Belgium |
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no |
Call Number |
BT @ osquigui @ |
Serial |
413 |
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Author |
Nakamura, O.; Chan, I.; Guimpel, J.; Schuller, I. |
Title |
New buffer layer for high?temperature superconducting ceramics on sapphire: LaBa2Cu3Oy/Ag bilayers |
Type |
Journal Article |
Year  |
1991 |
Publication |
Applied Physics Letters |
Abbreviated Journal |
Appl. Phys. Lett. |
Volume |
59 |
Issue |
10 |
Pages |
1245 |
Keywords |
Superconducting Films; Fabrication; High?Tc Superconductors; Lanthanum Oxides; Barium Oxides; Copper Oxides; Silver; Superconducting Junctions; Superconductivity; Dysprosium Oxides; Sputtering; Sapphire; Crystal Structure; Crystal Growth; Very High Temperature |
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Aip |
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no |
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BT @ jguimpel @ |
Serial |
611 |
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Author |
Vanacken, J.; Libbrecht, S.; Maenhoudt, M.; Van Haesendonck, C.; Osquiguil, E.; Bruynseraede, Y. |
Title |
The magnetic moment relaxation in oxygen-deficient YBa2Cu3Ox |
Type |
Journal Article |
Year  |
1992 |
Publication |
Physica C: Superconductivity and its applications |
Abbreviated Journal |
Phys C Supercond Appl |
Volume |
197 |
Issue |
1-2 |
Pages |
9-14 |
Keywords |
Magnetic Measurements – Relaxation; Oxygen – Concentration; Relaxation Processes – High Temperature Effects; Relaxation Processes – Magnetic Field Effects; Magnetic Moment Relaxation; Oxygen Deficiency; Yttrium Barium Copper Oxides; High Temperature Superconductors |
Abstract |
The magnetic moment relaxation in polycrystalline YBa2Cu3Oxmaterial has been studied using zero-field-cooled measurements. The temperature dependence of the relaxation rate shows a field-dependent maximum. When the oxygen content is reduced, the maximum shifts towards lower temperatures. This shift is directly related to a decrease of the intragrain critical current density in the oxygen-deficient material, inducing a decrease of the field H* for complete flux penetration. The characteristic activation energies for depinning in the oxygen-deficient material are below 20 meV. |
Address |
Laboratorium voor Vaste Stof-Fysika en Magnetisme, Katholieke Universiteit Leuven, Celestijnenlaan 200 D, B-3001 Leuven, Belgium |
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09214534 (ISSN) |
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Export Date: 17 April 2009; Source: Scopus; CODEN: PHYCE; Language of Original Document: English; Correspondence Address: Vanacken, J.; Laboratorium voor Vaste Stof-Fysika en Magnetisme; Katholieke Universiteit Leuven; Celestijnenlaan 200 D B-3001 Leuven, Belgium |
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no |
Call Number |
BT @ osquigui @ |
Serial |
409 |
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Author |
Luzuriaga, J.; Andre, M.-O.; Benoit, W. |
Title |
Frequency and amplitude response of the flux-line lattice to mechanical perturbation in ceramic YBa2Cu3O7 |
Type |
Journal Article |
Year  |
1992 |
Publication |
Physica C: Superconductivity and its applications |
Abbreviated Journal |
Phys C Supercond Appl |
Volume |
201 |
Issue |
3-4 |
Pages |
257-262 |
Keywords |
Copper oxides; Crystal lattices; Frequency response; Internal friction; Lattice vibrations; Magnetic fields; Mathematical models; Mechanical properties; Pendulums; Rheology; Thermal effects; Torque; Yttrium compounds; Amplitude response; Ceramic yttrium barium copper oxides; Extended dry friction model; Flux line lattices; Forced pendulum; Frequency independent dissipation peak; Mechanical response; Thermal activation; High temperature superconductors |
Abstract |
The mechanical response of the flux-line lattice has been measured with a low-frequency forced pendulum in ceramic YBa2Cu3O7. A dissipation peak observed in temperature sweeps is frequency-independent between 1 mHz and 5 Hz. Dissipation depends strongly on applied torque, and for fixed temperatures this dependence is well fitted by a rheological model of extended dry friction. If the model is extended to take account of thermal activation, however, it does not agree with the measured frequency independence, which is hard to explain within simple models of thermal activation. |
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Institut de G |
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09214534 (ISSN) |
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Export Date: 28 April 2009; Source: Scopus; CODEN: PHYCE; Language of Original Document: English; Correspondence Address: Luzuriaga, J.; Institut de G |
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BT @ luzuriag @ |
Serial |
487 |
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