| Records |
| Author |
Rodr |
| Title |
Role of anisotropy in the vortex lattice of superconductors high-Q oscillator measurements in 2H-NbSe2 and La1.825Sr0.075CuO4 |
Type |
Journal Article |
| Year |
1994 |
Publication |
Physica C: Superconductivity and its applications |
Abbreviated Journal |
Phys C Supercond Appl |
| Volume |
229 |
Issue |
1-2 |
Pages |
59-64 |
| Keywords |
Anisotropy; Copper oxides; High temperature superconductors; Lanthanum compounds; Magnetic field effects; Niobium compounds; Oscillators (mechanical); Phase transitions; Superconductivity; Thickness measurement; Angular dependence; Ginzburg Landau theory; Pinning; Crystal lattices |
| Abstract |
Measurement of the response of the flux-line lattice in NbSe2 and La1.825Sr0.075CuO4 show important differences between these two materials. In particular, we have studied the magnetic-field and angular dependence of the response of a high-Q mechanical oscillator in fields of up to 1 T. The features seen in NbSe2 seem to be well explained in terms of a change in the pinning regime, usually termed the “peak effect” in the critical current, using the collective-pinning model of Larkin and Ovchivnikov within Ginzburg-Landau anisotropic theory. On the other hand the behavior found in the high-Tc material LSCO seems to fall naturally into a description which takes into account the possibility of phase transitions in the vortex lattice and the quasi-two-dimensional character of the superconductivity. |
| Address |
AT and T Bell Laboratories, Murray hill, NJ 07974, USA |
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09214534 (ISSN) |
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Cited By (since 1996): 2; Export Date: 28 April 2009; Source: Scopus; CODEN: PHYCE; Language of Original Document: English; Correspondence Address: Luzuriaga, J.; Comisi |
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| Call Number |
BT @ luzuriag @ |
Serial |
520 |
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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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ISI:A1991FA71400006 |
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no |
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BT @ hernan @ |
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256 |
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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. |
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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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BT @ osquigui @ |
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409 |
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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. |
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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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BT @ osquigui @ |
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413 |
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| Author |
Watt |
| Title |
Photoinduced changes in Raman spectra of YBa2Cu3O6.4 films |
Type |
Journal Article |
| Year |
1994 |
Publication |
Journal of Superconductivity |
Abbreviated Journal |
J Supercond |
| Volume |
7 |
Issue |
1 |
Pages |
131-136 |
| Keywords |
Electronic Raman scattering; oxygen ordering; photoinduced superconductivity; two-magnon scattering; Copper oxides; Radiation effects; Raman spectroscopy; Superconducting films; Superconductivity; Oxide superconductors; Photoinduced effects; Yttrium barium cuprates; High temperature superconductors |
| Abstract |
The evolution of Raman spectra with illumination has been studied in YBa2Cu3O6.4 films at temperatures between 5-300 K. Low laser power has always been used to avoid local overheating, which was controlled by measuring the local temperature by the Stokes/anti-Stokes ratio. Three important photoinduced effects have been found: (i) the enhancement of the intensity of the observed phonon modes: (Cu(2) at 141 cm-1, O(2)-O(3) at 338 cm-1, and O(4) at 488 cm-1), which may be related to the ordering of oxygen vacancies, (ii) the increase of the electronic scattering background for low Raman frequencies ?, which is in agreement with the enhancement of the static conductivity ?(??0) after illumination, and (iii) the suppression of the intensity of the two-magnon band, which may be caused by the increase of charge carriers due to photodoping. |
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Laboratorium voor Vaste Stof-Fysika en Magnetisme, KU Leuven, Leuven, B-3001, Belgium |
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Kluwer Academic Publishers-Plenum Publishers |
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08961107 (ISSN) |
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Cited By (since 1996): 11; Export Date: 17 April 2009; Source: Scopus; CODEN: JOUSE; doi: 10.1007/BF00730383; Language of Original Document: English; Correspondence Address: Watt |
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BT @ osquigui @ |
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396 |
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