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Author (up) 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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ISSN 00381098 (ISSN) ISBN Medium
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Notes 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 Approved no
Call Number BT @ osquigui @ Serial 414
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Author (up) 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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ISSN 09214534 (ISSN) ISBN Medium
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Notes 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 Approved no
Call Number BT @ osquigui @ Serial 410
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Author (up) 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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ISSN 00381098 (ISSN) ISBN Medium
Area Expedition Conference
Notes Export Date: 17 April 2009; Source: Scopus; CODEN: SSCOA; Language of Original Document: English; Correspondence Address: Esparza, D.A.; Applied Research Department; Centro At Approved no
Call Number BT @ osquigui @ Serial 418
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Author (up) Libbrecht, S.; Osquiguil, E.; Wuyts, B.; Maenhoudt, M.; Gao, Z.X.; Bruynseraede, Y.
Title Effect of room temperature annealing on the properties of oxygen- deficient YBa2Cu3Ox films Type Journal Article
Year 1993 Publication Physica C: Superconductivity and its applications Abbreviated Journal Phys C Supercond Appl
Volume 206 Issue 1-2 Pages 51-58
Keywords Annealing; Ceramic materials; Hall effect; Superconducting films; Yttrium compounds; Critical current density; Oxide superconductors; Yttrium barium copper oxides; High temperature superconductors
Abstract Annealing at room temperature of quenched oxygen-depleted YBa2Cu3Oxn (6.5?xn<6.8) films, produces a clear increase in the critical temperature Tc and current density Jc, while the normal state resistivity ?{variant}xx and Hall coefficient RH decrease as a function of annealing time, indicating an increase in carrier density. The enhancement of the critical current density Jc is more pronounced at high fields and temperatures due to a shift of the irreversibility line, which scales with the increasing Tc. The observed changes are accompanied by corresponding changes in the crystalline structure, which can be related to oxygen ordering effects.
Address Laboratorium voor Vaste Stof-Fysika en Magnetisme, Katholieke Universiteit Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium
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ISSN 09214534 (ISSN) ISBN Medium
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Notes Cited By (since 1996): 11; Export Date: 17 April 2009; Source: Scopus; CODEN: PHYCE; Language of Original Document: English; Correspondence Address: Libbrecht, S.; Laboratorium voor Vaste Stof-Fysika en Magnetisme; Katholieke Universiteit Leuven; Celestijnenlaan 200D B-3001 Leuven, Belgium Approved no
Call Number BT @ osquigui @ Serial 402
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Author (up) Núñez Regueiro, M.; Esquinazi, P.; Izbizky, M.A.; Duran, C.; Castello, D.; Luzuriaga, J.; Nieva, G.
Title Evidence of tunneling systems through thermal and acoustic measurements in ceramic materials Type Journal Article
Year 1988 Publication Physica C: Superconductivity and its applications Abbreviated Journal Physica C
Volume 153-155 Issue PART 2 Pages 1016-1017
Keywords Acoustic Variables Measurement--Wave Velocity; Ceramic Materials--Thermal Conductivity; Europium Barium Copper Oxides; Superconducting Materials
Abstract We have neasured the sound velocity, internal friction, thermal conductivity and specific heat of La-based and (Y/Eu)- based ceramics. The low temperature data can be understood in terms of the Tunneling Model assuming the existence of Tunneling Systems (TS). From these measured properties we obtain values for the parameter C=P?2/?v2, where P is the density of states of TS, ? the coupling constant between phonons and TS, ? the mass density and v the sound velocity close to those obtained for amorphous and “orientational” disordered crystalline materials. Our data would indicate that the TS are intrinsic defects independent of the sample porosity.
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Area Expedition Conference International Conference on High Temperature Superconductors and Materials and Mechanisms of Superconductivity
Notes Export Date: 28 April 2009; Source: Scopus; CODEN: PHYCE; Language of Original Document: English; Correspondence Address: Regueiro, M.N.; Centro At Approved no
Call Number BT @ luzuriag @ Serial 496
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Author (up) 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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ISSN 00381098 (ISSN) ISBN Medium
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Notes Export Date: 17 April 2009; Source: Scopus; CODEN: SSCOA; Language of Original Document: English; Correspondence Address: Osquiguil, E. Approved no
Call Number BT @ osquigui @ Serial 416
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Author (up) Osquiguil, E.; Maenhoudt, M.; Wuyts, B.; Bruynseraede, Y.; Lederman, D.; Nieva, G.; Guimpel, J.; Schuller, I.K.
Title Photoexcitation effects in YBa2Cu3Ox Type Journal Article
Year 1993 Publication Journal of Alloys and Compounds Abbreviated Journal J Alloys Compd
Volume 195 Issue C Pages 667-670
Keywords Barium compounds; Ceramic materials; Copper oxides; High temperature superconductors; Oxides; Photoelectricity; Yttrium compounds; C-axis oriented films; Photoexcitation effects; Photoinduced phenomena; Yttrium barium cuprates; Superconducting films
Abstract We show through photoexcitation experiments carried out on YBa2Cu3Ox c-axis oriented films that photoinduced phenomena are not restricted to insulating samples. Superconducting films with critical temperatures varying between 2 K and 40 K show a clear enhancement of the superconducting transition after illumination. The increase in Tc is accompanied by a corresponding decrease in the resistivity ?, and an increase in the Hall coefficient RH, indicative of an increased carrier density. Furthermore, the carrier mobility is also affected by illumination.
Address Physics Department – 0319, University of California – San Diego, La Jolla, CA 92093-0319, United States
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ISSN 09258388 (ISSN) ISBN Medium
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Notes Cited By (since 1996): 4; Export Date: 17 April 2009; Source: Scopus; CODEN: JALCE; Language of Original Document: English; Correspondence Address: Osquiguil, E.; Laboratorium voor Vaste Stof-Fysika en Magnetisme; Katholieke Universiteit Leuven B-3001 Leuven, Belgium Approved no
Call Number BT @ osquigui @ Serial 401
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Author (up) 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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Notes ISI:A1991FA71400006 Approved no
Call Number BT @ hernan @ Serial 256
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Author (up) 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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ISSN 09214534 (ISSN) ISBN Medium
Area Expedition Conference
Notes 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 Approved no
Call Number BT @ osquigui @ Serial 413
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