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Author (up) Esquinazi, P.; Luzuriaga, J.
Title Annealing effects on the sound velocity and internal friction in the superconducting and normal states of the Cu30Zr70 amorphous alloy Type Journal Article
Year 1988 Publication Physical Review B Abbreviated Journal
Volume 37 Issue 13 Pages 7819-7831
Keywords Zr70Cu30
Abstract By means of the vibrating-reed technique we have measured the evolution upon low-temperature annealing of the internal friction Q-1 and sound velocity v of the Cu30Zr70 amorphous alloy between 0.1 and 10 K. With an applied magnetic field of 5.6 T we measured also the normal-state behavior of both properties. Upon annealing, the internal friction and the slope of the logarithmic temperature dependence of v in the superconducting state decrease, in agreement with the standard tunneling model. Our results indicate that with thermal treatments, the coupling constant between tunneling systems (TSs) and phonons decreases, and the density of states of the TS remains constant or decreases, at most 25%, in the fully relaxed state, which is in agreement with published specific-heat results in these materials. From our data we conclude that the coupling constant between the TS and phonons should be very sensitive to the relaxed state of the disordered structure. The sound-velocity behavior strongly indicates that relaxation processes up to 10 K involve the interaction with the TS. A well-defined change of slope in v at the superconducting critical temperature Tc is observed in the as-quenched and the first relaxed state, which cannot be explained with the standard tunneling model and the Korringa-like relaxation rate between the TS and electrons. Several features observed in the superconducting and normal states lead to the conclusion that the TS-electron interaction problem remains unsolved.
Address Centro Atómico Bariloche, Instituto Balseiro, 8400 Bariloche, Argentina
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ISSN 01631829 (ISSN) ISBN Medium
Area Expedition Conference
Notes Cited By (since 1996): 9; Export Date: 28 April 2009; Source: Scopus; doi: 10.1103/PhysRevB.37.7819; Language of Original Document: English; Correspondence Address: Esquinazi, P.; Centro Atmico Bariloche; Instituto Balseiro 8400 Bariloche, Argentina Approved no
Call Number BT @ luzuriag @ Serial 494
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Author (up) Esquinazi, P.; Luzuriaga, J.; Durán, C.
Title Vibrating-reed studies of flux pinning in the superconducting metallic glass Zr70Cu30 Type Journal Article
Year 1988 Publication Physical Review B Abbreviated Journal
Volume 37 Issue 7 Pages 3689-3692
Keywords
Abstract With the vibrating-reed technique we have measured the resonance frequency and damping of superconducting ribbons of a Zr70Cu30 amorphous alloy as a function of magnetic field and temperature for different heat treatments of the same sample. Through these measurements we obtain the Labusch parameter in the reduced-field (b) range 5
Address Centro Atomico Bariloche, Instituto Balseiro, 8400 Bariloche, Argentina
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Series Editor Series Title Abbreviated Series Title
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ISSN 01631829 (ISSN) ISBN Medium
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Notes Export Date: 28 April 2009; Source: Scopus; doi: 10.1103/PhysRevB.37.3689; Language of Original Document: English; Correspondence Address: Esquinazi, P.; Centro Atomico Bariloche; Instituto Balseiro 8400 Bariloche, Argentina Approved no
Call Number BT @ luzuriag @ Serial 495
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Author (up) Esquinazi, P.; Luzuriaga, J.; Durán, C.; Esparza, D.A.; D'Ovidio, C.
Title Anomalies in the internal friction and sound velocity in the high-temperature superconductor La1.8Sr0.2CuO4 Type Journal Article
Year 1987 Publication Physical Review B Abbreviated Journal Phys. Rev. B
Volume 36 Issue 4 Pages 2316-2318
Keywords
Abstract The internal friction Q-1 and the Young's-modulus sound velocity vE have been measured in La1.8Sr0.2CuO4 using the vibrating-reed technique. Measurements were performed at a frequency of 700 Hz at temperatures between 0.2 and 100 K. A drastic change of slope in the internal friction versus temperature curve is observed at T=44 K just above the superconducting transition temperature Tc=40 K. A plateau in Q-1 is observed between 44 and 5 K. The sound velocity shows a decrease with decreasing temperature between 100 and 20 K and remains almost constant between 2 and 0.2 K.
Address Centro Atomico Bariloche, Instituto Balseiro, 8400 Bariloche, Argentina
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Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
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ISSN 01631829 (ISSN) ISBN Medium
Area Expedition Conference
Notes Cited By (since 1996): 6; Export Date: 28 April 2009; Source: Scopus; doi: 10.1103/PhysRevB.36.2316; Language of Original Document: English; Correspondence Address: Esquinazi, P.; Centro Atomico Bariloche; Instituto Balseiro 8400 Bariloche, Argentina Approved no
Call Number BT @ luzuriag @ Serial 498
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Author (up) Giordano, J.L.; Luzuriaga, J.; Badía-Majós, A.; Nieva, G.; Ruiz-Tagle, I. A.
Title Magnetization collapse in polycrystalline YBCO under transport current cycles Type Journal Article
Year 2006 Publication Superconducting Science and Technology Abbreviated Journal Supercond. Sci. Technol.
Volume 19 Issue 4 Pages 385-391
Keywords
Abstract We report measurements of the hysteretic magnetization of YBCO under superimposed transport current cycles, together with numerical simulations of magnetization and current density profiles in the corresponding parallel configuration. Field cooled (FC) and zero-field-cooled (ZFC) experiments were carried out on polycrystalline YBa2Cu3O7?x cylinders, with both the applied magnetic field and transport current in the axial direction, and the current cycled several times, around and above the dissipative threshold. As in previously reported multicomponent field configuration experiments, the magnetization is seen to collapse to a more stable state both in FC and ZFC, because of the interplay between the shielding and transport currents. The results of our numerical simulations are in good qualitative agreement with the measurements, and the competition between shielding and transport due to vortex-pinning interactions and equilibrium magnetization effects are shown to play an important role in the range of our experiments.
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ISSN 0953-2048 ISBN Medium
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Notes Approved no
Call Number BT @ gnieva @ Serial 467
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Author (up) Giordano, J.L.; Luzuriaga, J.; Ruíz-Tagle,; NIEVA, G.; Badía-Majós,
Title Magnetization measurements of hard superconductors under dissipative transport Type Journal Article
Year 2006 Publication Journal of Physics: Conference Series Abbreviated Journal J. Phys. Conf. Ser.
Volume 43 Issue 1 Pages 663-666
Keywords
Abstract The hysteretic magnetic flux dynamics of ceramic type-II superconductors under superimposed transport current cycles has been investigated. Field cooled and zero field cooled experiments were carried-out on polycrystalline YBa 2Cu3O7-x cylinders by using both temperature and applied field control, to drive the sample into the semi-reversible granular regime. The transport current magnitude was near and above the dissipative threshold. The interplay between shielding and transport due to vortex-pinning interactions, equilibrium magnetization effects, and diamagnetic/paramagnetic relaxation phenomena are shown to play an important role in the range of practical applications.
Address Departamento de F
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Series Editor Series Title Abbreviated Series Title
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ISSN 17426588 (ISSN) ISBN Medium
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Notes Export Date: 28 April 2009; Source: Scopus; Art. No.: 162; doi: 10.1088/1742-6596/43/1/162; Language of Original Document: English; Correspondence Address: Giordano, J.L.; Departamento de Ciencias de la Ingenier Approved no
Call Number BT @ luzuriag @ Serial 471
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Author (up) Godfrin, H.; Luzuriaga, J.; Collin, E.; Guimpel, J. (eds)
Title Frontiers of Low Temperature Physics ULT-2014 Type Conference Volume
Year 2014 Publication Abbreviated Journal
Volume Issue Pages
Keywords
Abstract Abstract book for the Ultra-Low Temperatures conference held at S.C. de Bariloche as a satellite to the LT27.
Address
Corporate Author Thesis
Publisher Place of Publication Editor Godfrin, H.; Luzuriaga, J.; Collin, E.; Guimpel, J.
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Notes Approved no
Call Number BT @ pedrazp @ Serial 799
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Author (up) Herbsommer, J.A.; Correa, V.F.; Nieva, G.; Pastoriza, H.; Luzuriaga, J.
Title Vortex dynamics in Bi2Sr2CaCu2O8+δ single crystals with planar defects Type Journal Article
Year 2001 Publication Solid State Communications Abbreviated Journal Solid State Commun.
Volume 120 Issue 2-3 Pages 59-63
Keywords
Abstract We have studied the effects of c-axis correlated planar defects on the vortex lattice of Bi$2$Sr$2$CaCu$8$ single crystals using Bitter decoration, transverse ac permeability and X-ray measurements. Our results show that the low field low temperature phase coherent vortex lattice exhibits anisotropic pinning in the presence of these planar defects. Frequency dependent ac permeability measurements show that the ordered solid-liquid transition is first order as in samples free of correlated defects. However, the melting point is detected only when the excitation field is along the defects.
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Call Number BT @ hernan @ herbsommer01 Serial 23
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Author (up) Herbsommer, J.A.; Luzuriaga, J.; Cheong, S.-W.
Title Vortex glass melting in single crystal La1.825 Sr0.075CuO4 Type Journal Article
Year 1996 Publication Physica C Abbreviated Journal Physica C
Volume 258 Issue 1-2 Pages 169-174
Keywords Copper compounds; Crystal lattices; Frequency response; Glass; Magnetic field measurement; Magnetic permeability measurement; Melting; Phase diagrams; Single crystals; Temperature; Vortex flow; AC susceptibility; Cuprates; Pinned flux lattice; Oxide superconductors
Abstract The vortex phase diagram in single crystalline La1.85Sr0.075CuO4 has been studied using an AC-susceptibility technique. A peak in the out-of-phase (x?) component of the susceptibility indicates a transition from a pinned flux lattice (FLL) to an unpinned one. This peak is frequency dependent for all the values of the magnetic field measured (0.01 to 4 T), and this, as well as the general behavior found in the cuprates, has prompted us to interpret our data as evidence for a vortex-glass to liquid transition in the FLL. The activation energies obtained can be fitted to a theory developed by Vinokur et al. Measurements with the magnetic field at an angle with the Cu-O planes may also be understood qualitatively within this framework.
Address AT and T Bell Laboratories, Murray Hill, NJ, United States
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ISSN 09214534 (ISSN) ISBN Medium
Area Expedition Conference
Notes Cited By (since 1996): 2; Export Date: 28 April 2009; Source: Scopus; CODEN: PHYCE; doi: 10.1016/0921-4534(95)00812-8; Language of Original Document: English; Correspondence Address: Luzuriaga, J.; Centro At Approved no
Call Number BT @ luzuriag @ Serial 483
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Author (up) Herbsommer, J.A.; Luzuriaga, J.; Civale, L.; Nieva, G.; Pasquini, G.; Lanza, H.; Levy, P.
Title Angular variation of pinning near the irreversibility temperature in single crystal Y Ba2Cu3O7-? with splayed columnar defects Type Journal Article
Year 1998 Publication Physica C Abbreviated Journal Physica C
Volume 304 Issue 1-2 Pages 112-118
Keywords Columnar defects; Critical current density; Flux pinning; Pinning force; Anisotropy; Critical current density (superconductivity); Crystal defects; Single crystals; Columnar defects; Flux pinning; Yttrium barium copper oxides
Abstract We have studied vortex pinning through ac susceptibility measurements in single crystals of YBCO with columnar defects (CDs). The CDs have 0, 10 and 20 splay angle and average direction 108 off the c-axis. By studying the angular variation we can compensate for the anisotropy and effects of twins, etc. Using a simple expression we can obtain the angular spread when the field direction is outside the splay angle. An increase of pinning when the field direction is inside

the angle defined by the CDs can be attributed to vortex entanglement due to the splay and the suppression of the sliding of double kinks.
Address Departamento de F
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ISSN 09214534 (ISSN) ISBN Medium
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Notes Cited By (since 1996): 10; Export Date: 28 April 2009; Source: Scopus; CODEN: PHYCE; Language of Original Document: English; Correspondence Address: Herbsommer, J.A.; Ctro. Atom. Bariloche Inst. Balseiro; CNEA and UNC 8400 Bariloche, Argentina; References: Civale, L., Marwick, A.D., Worthington, T.K., Kirk, M.A., Thompson, J.R., Krusin-Elbaum, L., Sun, Y., Holtzberg, F., (1991) Phys. Rev. Lett., 67, p. 648; Hwa, T., Doussal, P.L., Nelson, D.R., Vinokur, V.M., (1993) Phys. Rev. Lett., 71, p. 3545; Civale, L., Krusin-Elbaum, L., Thompson, J.R., Wheeler, R., Marwick, A.D., Kirk, M.A., Sun, Y.R., (1994) Phys. Rev. B, 50, p. 4102; Krusin-Elbaum, L., Thompson, J.R., Wheeler, R., Marwick, A.D., Li, C., Patel, S., Shaw, D.T., Ullmann, J., (1994) Appl. Phys. Lett., 64, p. 3331; Hardy, V., Whal, A., Hebert, S., Ruyler, A., Provost, J., Groult, D., Simon, C., (1996) Phys. Rev. B, 54, p. 656; Hardy, V., Ruyter, A., Whal, A., Maignan, A., Groult, D., Provost, J., Simon, C., Noel, H., (1996) Physica C, 257, p. 16; Krusin-Elbaum, L., Marwick, A.D., Wheeler, R., Feild, C., Vinokur, V.M., Leaf, G.K., Palumbo, M., (1996) Phys. Rev. Lett., 76, p. 2563; Prozorov, R., Konczykowski, M., Schmidt, B., Yeshurun, Y., Shaulov, A., Villard, C., Koren, G., (1996) Phys. Rev. B, 54, p. 15530; De La Cruz, F., L Approved no
Call Number BT @ luzuriag @ Serial 517
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Author (up) Herbsommer, J.A.; Nieva, G.; Luzuriaga, J.
Title Reproducibility of the disordered vortex structure in twinned single crystals of YBCO Type Journal Article
Year 2000 Publication Physica C Abbreviated Journal Physica C
Volume 341 Issue Pages 1087-1088
Keywords
Abstract Bitter decorations of the vortices in twinned single crystal YBCO have been obtained to study the disordered structure formed on successive cooldowns of the sample under the same conditions of field and temperature. Between succesive decorations, the iron dots could be removed completely, giving a surface clean enough for further decoration. It was found that successive realizations of the disordered vortex state were very similar at long range, and differed mostly on short scales, compared to the average vortex separation. We have quantified the correlation between successive structures, and double sided decorations have been also performed to compare with the extent of spatial correlation in the applied field direction. The coincidence of the position of the vortices in successive realizations of the structure, is unexpected, and indicates an unusual behavior for a glassy system. Our technique makes it possible to image the position of the vortices in detail and repeatedly, providing us with a model amorphous system in which to study the reproducibility of the disordered structure.
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ISSN 0921-4534 ISBN Medium
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Notes ISI:000165855700143 Approved no
Call Number BT @ hernan @ Serial 220
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