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Author Gao, Z.X.; Heyvaert, I.; Wuyts, B.; Osquiguil, E.; Haesendonck, C.V.; Bruynseraede, Y.
Title Evidence for a “brick wall” microstructure in epitaxial YBa 2Cu3Ox films Type Journal Article
Year 1994 Publication Applied Physics Letters Abbreviated Journal
Volume 65 Issue 6 Pages 770-772
Keywords
Abstract We have measured the in-plane (ab plane) critical current density J c in sputtered, c-axis oriented YBa2Cu3O x films as a function of the oxygen content x. The important reduction of Jc with decreasing x can be explained in terms of a “brick wall” microstructure, where the critical current density is dominated by the coupling strength (along the c axis) between the superconducting CuO 2 planes. Scanning tunneling microscopy images of the film surfaces are consistent with the presence of the brick wall structure, which apparently results from the overlap between terraces belonging to adjacent spiral-shaped islands.
Address Laboratorium voor Vaste-Stoffysica en Magnetisme, Katholieke Universiteit Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium
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ISSN 00036951 (ISSN) ISBN Medium
Area Expedition Conference
Notes Export Date: 17 April 2009; Source: Scopus; doi: 10.1063/1.112225; Language of Original Document: English; Correspondence Address: Gao, Z.X.; Laboratorium voor Vaste-Stoffysica en Magnetisme; Katholieke Universiteit Leuven; Celestijnenlaan 200D B-3001 Leuven, Belgium Approved no
Call Number (up) BT @ osquigui @ Serial 391
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Author Wuyts, B.; Maenhoudt, M.; Libbrecht, S.; Gao, Z.X.; Osquiguil, E.; Moshchalkov, V.V.; Bruynseraede, Y.
Title Linear relation between the Hall angle slope and the carrier density in YBa2Cu3Ox films Type Journal Article
Year 1994 Publication Physica C: Superconductivity and its applications Abbreviated Journal Phys C Supercond Appl
Volume 235-240 Issue PART 2 Pages 1369-1370
Keywords
Abstract A universal relation cot?H??{variant}/RHB = ?T2 + C for the Hall angle ?H has been experimentally observed served in a wide variety of high-Tc systems. In contrast to the linear temperature dependence of the resistivity ?{variant} or the inverse Hall coefficient R-1H, the T2-dependence of cot?H remains valid in under- and overdoped systems. We present a systematic study of cot?H(T) in oxygen deficient epitaxial YBa2Cu3Ox thin films. We find evidence for a linear relation between ?, the slope of cot?H versus T2, and the carrier concentration. Moreover, we find a steep increase in the intercept C = cot?H (T = 0) below x ? 6.6.
Address Laboratorium voor Vaste-Stoffysika en Magnetisme, Katholieke Universiteit Leuven Celestijnenlaan 200D, B-3001 Leuven, Belgium
Corporate Author Thesis
Publisher Place of Publication Editor
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Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 09214534 (ISSN) ISBN Medium
Area Expedition Conference
Notes Export Date: 17 April 2009; Source: Scopus; CODEN: PHYCE; Language of Original Document: English; Correspondence Address: Wuyts, B.; Laboratorium voor Vaste-Stoffysika en Magnetisme; Katholieke Universiteit Leuven Celestijnenlaan 200D B-3001 Leuven, Belgium Approved no
Call Number (up) BT @ osquigui @ Serial 392
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Author van Dalen, A.J.J.; Griessen, R.; Libbrecht, S.; Osquiguil, E.; Bruynseraede, Y.
Title Observation of quantum creep in oxygen deficient YBa2Cu3O7-? at fields up to 7 T Type Journal Article
Year 1994 Publication Physica C: Superconductivity and its applications Abbreviated Journal Phys C Supercond Appl
Volume 235-240 Issue PART 5 Pages 2959-2960
Keywords
Abstract Superconducting current densities js and dynamic relaxation rates Q ? d ln js/d ln (dBe/dt) in an oxygen deficient YBa2Cu3O7-? epitaxial film were measured as a function of temperature (1.5K < T < Tirr) in magnetic fields up to 7 T by means of high sensitivity capacitance torquemeters. Below 5 K, the relaxation rate remains high and does not extrapolate to Q = 0 at T = 0K. This is associated to the quantum tunneling of vortices through the energy barrier separating two adjacent vortex configurations. In the case of ohmic dissipation the quantum creep rate is proportional to the normal state resistivity ?{variant}n(0) at T = 0 K. In order to check this theoretical prediction we measured Q as a function of the oxygen content of the sample. The quantum creep rate increases systematically with increasing ?{variant}n(0). However, Q remains finite even when ?{variant}n = 0.
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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: van Dalen, A.J.J.; Faculty of Physics and Astronomy; Free University 1081 HV Amsterdam, Netherlands Approved no
Call Number (up) BT @ osquigui @ Serial 393
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Author Libbrecht, S.; Osquiguil, E.; Bruynseraede, Y.
Title Influence of field inhomogeneity on the magnetization of YBCO films Type Journal Article
Year 1994 Publication Physica C: Superconductivity and its applications Abbreviated Journal Phys C Supercond Appl
Volume 225 Issue 3-4 Pages 337-345
Keywords Magnetization; Superconducting films; SQUID magnetometers; Superconducting ceramics; YBCO superconductors; High temperature superconductors
Abstract DC magnetization data of superconducting thin YBCO films, measured by means of a magnetometer in which the sample is pulled through a set of pick-up coils, are often calculated from pick-up signals which clearly deviate from the ideal response. We show how these signal distortions influence the values obtained for the magnetization, and present a simple model that enables one to simulate the temperature dependence of these distorted pick-up signals, in the case of low-field magnetization measurements. The model is based on the magnetic field inhomogeneity of the magnetometer, in combination with the hysteretic magnetization of the superconducting sample. Optimum values for the model parameters are derived and discussed.
Address Laboratorium voor Vaste Stof-Fysika en Magnetisme, Katholieke Universiteit Leuven, Celestijnenlaan 200 D, B-3001 Leuven, Belgium
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 09214534 (ISSN) ISBN Medium
Area Expedition Conference
Notes Cited By (since 1996): 11; Export Date: 17 April 2009; Source: Scopus; CODEN: PHYCE; Language of Original Document: English; Correspondence Address: Bruynseraede, Y.; Laboratorium voor Vaste Stof-Fysika en Magnetisme; Katholieke Universiteit Leuven; Celestijnenlaan 200 D B-3001 Leuven, Belgium Approved no
Call Number (up) BT @ osquigui @ Serial 394
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Author Wuyts, B.; Osquiguil, E.; Maenhoudt, M.; Libbrecht, S.; Gao, Z.X.; Bruynseraede, Y.
Title Relation between the Hall angle slope and the carrier density in oxygen-depleted YBa2Cu3Ox films Type Journal Article
Year 1994 Publication Physica C: Superconductivity and its applications Abbreviated Journal Phys C Supercond Appl
Volume 222 Issue 3-4 Pages 341-348
Keywords Doping (additives); Electric conductivity; Hall effect; Mathematical models; Thermal effects; Thin films; Transport properties; Yttrium compounds; Carrier density; Hall angle slope; Oxygen content; Zero temperature intercept; Superconducting films
Abstract A detailed study of the Hall angle cot?H in YBa2Cu3Ox epitaxial thin films with various oxygen contents clearly shows the existence of a linear relation between the slope of cot?H versus T2 and the carrier density. The zero-temperature intercept C=cot?H(T=0 K) and the mobility at room temperature change substantially for an oxygen content x?6.6, indicating that both effects are closely related.
Address Laboratorium voor Vaste Stof-Fysika en Magnetisme, Katholieke Universiteit Leuven, Celestijnenlaan 200 D, B-3001 Leuven, Belgium
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
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: Bruynseraede, Y.; Laboratorium voor Vaste Stof-Fysika en Magnetisme; Katholieke Universiteit Leuven; Celestijnenlaan 200 D B-3001 Leuven, Belgium Approved no
Call Number (up) BT @ osquigui @ Serial 395
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Author Lederman, D.; Osquiguil, E.; Nieva, G.; Guimpel, J.; Hasen, J.; Bruynseraede, Y.; Schuller, I.K.
Title Photoinduced enhancement of superconductivity Type Journal Article
Year 1994 Publication Journal of Superconductivity Abbreviated Journal J Supercond
Volume 7 Issue 1 Pages 127-130
Keywords photoconduction; Superconductivity; thin films; Copper oxides; Hall effect; Order disorder transitions; Radiation effects; Superconductivity; X ray analysis; Josephson coupling; Oxide superconductors; Yttrium barium cuprates; High temperature superconductors
Abstract The photoinduced enhancement of superconductivity in RBa2Cu3Ox (R=rare earth or yttrium) and PryR1-yBa2Cu3Ox was explored through temperature-dependent resistivity, Hall coefficient and mobility, and x-ray diffraction measurements. The increases in Tc are enhanced near the metal-insulator transition, although photoinduced changes always exist in oxygendeficient samples. Several explanations, including intergrain Josephson coupling, photoassisted oxygen ordering, and the trapping of photogenerated electrons in oxygen vacancies, are discussed.
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Publisher Kluwer Academic Publishers-Plenum Publishers Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 08961107 (ISSN) ISBN Medium
Area Expedition Conference
Notes Cited By (since 1996): 2; Export Date: 17 April 2009; Source: Scopus; CODEN: JOUSE; doi: 10.1007/BF00730382; Language of Original Document: English; Correspondence Address: Lederman, D.; Physics Department; University of California; San Diego La Jolla, 92093-0319, California, United States Approved no
Call Number (up) BT @ osquigui @ Serial 397
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Author Wuyts, B.; Osquiguil, E.; Maenhoudt, M.; Libbrecht, S.; Gao, Z.X.; Bruynseraede, Y.
Title Influence of the oxygen content on the normal-state Hall angle in YBa2Cu3Oxn films Type Journal Article
Year 1993 Publication Physical Review B Abbreviated Journal
Volume 47 Issue 9 Pages 5512-5515
Keywords
Abstract We report on measurements of in-plane resistivity ?ab(T) and Hall coefficient RH(T) in c-axis-oriented oxygen-deficient YBa2Cu3Oxn thin films. Independent of the changes induced in RH(T) and ?ab(T) by the oxygen depletion, a quadratic temperature dependence is observed for the Hall angle ?H. The slope of cot?H versus T2 decreases as the oxygen content xn is reduced and saturates in the Tc(xn)=60 K plateau region. The results are discussed in the framework of the two-dimensional Luttinger liquid theory as proposed by Anderson.
Address Laboratorium Voor Vaste Stof-Fysika en Magnetisme, Katholieke Universiteit Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium
Corporate Author Thesis
Publisher Place of Publication Editor
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Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 01631829 (ISSN) ISBN Medium
Area Expedition Conference
Notes Cited By (since 1996): 27; Export Date: 17 April 2009; Source: Scopus; doi: 10.1103/PhysRevB.47.5512; Language of Original Document: English; Correspondence Address: Wuyts, B.; Laboratorium Voor Vaste Stof-Fysika en Magnetisme; Katholieke Universiteit Leuven; Celestijnenlaan 200D B-3001 Leuven, Belgium Approved no
Call Number (up) BT @ osquigui @ Serial 398
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Author Osquiguil, E.; Gao, Z.X.; Maenhoudt, M.; Wuyts, B.; Libbrecht, S.; Bruynseraede, Y.
Title YBa2Cu3Ox: A natural multilayer system with tunable anisotropy Type Journal Article
Year 1993 Publication Journal of Physics: Condensed Matter Abbreviated Journal
Volume 5 Issue 33 A Pages
Keywords
Abstract The authors report on magnetoresistivity rho ab( theta ,H,T) measurements below Tc in YBa2Cu3Oxn films with differing oxygen content x. The observed variations in the angular and field dependence of rho ab with reduced x indicate a gradual dimensional crossover from an anisotropic 3D to a quasi-2D behaviour. The increasing anisotropy is related to a decrease of the coupling between the Cu2O2 bilayers when oxygen is removed from the Cu1Ox chain-planes.
Address Lab. voor Vaste Stof-Fysika en Magnetisme, Katholieke Univ. Leuven, Belgium
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Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 09538984 (ISSN) ISBN Medium
Area Expedition Conference
Notes Cited By (since 1996): 1; Export Date: 17 April 2009; Source: Scopus; Art. No.: 145; doi: 10.1088/0953-8984/5/33A/145; Language of Original Document: English; Correspondence Address: Osquiguil, E.; Lab. voor Vaste Stof-Fysika en Magnetisme; Katholieke Univ. LeuvenBelgium Approved no
Call Number (up) BT @ osquigui @ Serial 399
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Author Gao, Z.X.; Osquiguil, E.; Maenhoudt, M.; Wuyts, B.; Libbrecht, S.; Bruynseraede, Y.
Title 3D-2D dimensional crossover in YBa2Cu3O7 films Type Journal Article
Year 1993 Publication Physical Review Letters Abbreviated Journal
Volume 71 Issue 19 Pages 3210-3213
Keywords
Abstract We show that, in fully oxidized YBa2Cu3O7 c-axis oriented films, the changes induced in the angular and field dependence of the magnetoresistivity ?ab by increasing the temperature towards Tc are similar to those caused by a lowering in oxygen content. This remarkable behavior can be interpreted as due to a crossover from a three-dimensional to a two-dimensional system as T approaches Tc. Moreover, our critical current data mimic the behavior observed by Qi Li et al. in YBa2Cu3O7/(PrxY1-x)Ba2Cu3O7 multilayers, suggesting the possibility that chain planes are superconducting.
Address Laboratorium Voor Vaste Stof-Fysika en Magnetisme, Katholieke Universiteit Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium
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Series Volume Series Issue Edition
ISSN 00319007 (ISSN) ISBN Medium
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Notes Cited By (since 1996): 7; Export Date: 17 April 2009; Source: Scopus; doi: 10.1103/PhysRevLett.71.3210; Language of Original Document: English; Correspondence Address: Gao, Z.X.; Laboratorium Voor Vaste Stof-Fysika en Magnetisme; Katholieke Universiteit Leuven; Celestijnenlaan 200D B-3001 Leuven, Belgium Approved no
Call Number (up) BT @ osquigui @ Serial 400
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Author 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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Publisher Place of Publication Editor
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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 (up) BT @ osquigui @ Serial 401
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