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Author  |
Civale, L.; de la Cruz, F.; Luzuriaga, J. | ||||
| Title | Critical temperature and density of states in amorphous Zr70Cu30 | Type | Journal Article | ||
| Year | 1983 | Publication | Solid State Communications | Abbreviated Journal | Solid State Commun. |
| Volume | 48 | Issue | 4 | Pages | 389-391 |
| Keywords | ZIRCONIUM COPPER ALLOYS | ||||
| Abstract | By means of thermal heat treatment of amorphous Zr70Cu30 it is shown that the induced decrease in critical temperature is followed by a reduction in the electronic density of states of the same magnitude as that obtained by changing the Cu concentration. This result indicates that the density of states is the fundamental microscopic parameter determining the superconducting behavior. | ||||
| Address | Centro Atomico Bariloche | ||||
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| ISSN | 00381098 (ISSN) | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Cited By (since 1996): 1; Export Date: 28 April 2009; Source: Scopus; CODEN: SSCOA; Language of Original Document: English; Correspondence Address: Civale, L.; Centro At | Approved | no | ||
| Call Number | BT @ luzuriag @ | Serial | 503 | ||
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| Author |
Civale, L.; Safar, H.; de la Cruz, F. | ||||
| Title | Percolation and glass behavior in ceramic superconductors: oxygen effects | Type | Journal Article | ||
| Year | 1989 | Publication | Modern Physics Letters B | Abbreviated Journal | Mod. Phys. Lett. B |
| Volume | 3 | Issue | 2 | Pages | 173-181 |
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| Abstract | It is shown that small variations of oxygen content in La1.8Sr0.2CuO4−δ can be used to control the reversible and irreversible magnetization temperature dependence of the superconducting state. A grain bond model is appropriate to describe the superconducting response of the ceramics. The study of the temperature dependence of the magnetization and the resistive transition temperature, in a slightly deoxygenated sample, show that the reversible superconducting state is strongly correlated to superconducting percolation. Deoxygenation has been shown to be an excellent technique to study the time evolution of metastable states induced by currents in the bonds and or in the grains. It is shown that superconducting grains are not correlated to ceramic grains. | ||||
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| Notes | Approved | no | |||
| Call Number | BT @ pedrazp @ | Serial | 802 | ||
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| Author |
Correa, V.F.; Herbsommer, J.A.; Kaul, E.E.; de la Cruz, F.; Nieva, G. | ||||
| Title | Order-disorder transition and the zero-dimensional vortex pinning regime in Bi2Sr2CaCu2O8+delta | Type | Journal Article | ||
| Year | 2001 | Publication | PHYSICAL REVIEW B | Abbreviated Journal | |
| Volume | 63 | Issue | 9 | Pages | 092502 |
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| Abstract | We make a comparative study between the ab plane's dc critical current and the ac transverse magnetic permeability μ(perpendicular to) in the Campbell limit for optimally doped and overdoped Bi2Sr2CaCu2O8+delta samples. We focus attention on the low-temperature region [T/T-c(0) < 0.25], where the transition to the zero-dimensional Larkin limit is detected by the critical current as well as by a rapid change of the Labusch parameter with temperature. The order-disorder transition, characterized by the second peak in magnetization, disappears in the presence of this zero-dimensional pinning regime. | ||||
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| ISSN | 0163-1829 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | ISI:000167312000016 | Approved | no | ||
| Call Number | BT @ hernan @ | Serial | 218 | ||
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| Author |
Correa, V.F.; Herbsommer, J.A.; Kaul, E.E.; de la Cruz, F.; Nieva, G. | ||||
| Title | Onset of the 0-dimensional vortex pinning behavior in the optimally doped and overdoped Bi2Sr2CaCu2O8+delta system | Type | Journal Article | ||
| Year | 2000 | Publication | PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS | Abbreviated Journal | |
| Volume | 341 | Issue | Pages | 1285-1286 | |
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| Abstract | We report results of transverse AC magnetic permeability in the linear regime and DC magnetization loops for optimally doped and oxygen overdoped samples of Bi2Sr2CaCu2O8+delta The data cover the low temperature (T < 25K) and low held (H-a < 1000 Oe) region of the magnetic (H-a-T) phase diagram. In optimally doped as well as in overdoped samples a crossover to a O-dimensional pinning regime (Larkin length, L-C(C), shorter than the inter-plane CuO2 distance) is observed at a characteristic temperature Too for all investigated fields. The order-disorder transition, identified by the second peak in magnetization and a non monotonous field dependence of the AC penetration depth, is quenched below T-0D. | ||||
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| Series Volume | Series Issue | Edition | |||
| ISSN | 0921-4534 | ISBN | Medium | ||
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| Notes | ISI:000165855700242 | Approved | no | ||
| Call Number | BT @ hernan @ | Serial | 221 | ||
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| Author |
Correa, V.F.; Nieva, G.; de la Cruz, F. | ||||
| Title | Vortex softening: Origin of the second peak effect in Bi2Sr2CaCu2O8+delta | Type | Journal Article | ||
| Year | 2001 | Publication | PHYSICAL REVIEW LETTERS | Abbreviated Journal | |
| Volume | 87 | Issue | 5 | Pages | 057003 |
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| Abstract | Magnetic hysteresis and transverse ac permeability measurements in Bi2Sr2CaCu2O8+delta allow a comparative analysis of the critical current with the elastic response of vortex structures, in equilibrium with their pinning potential, in the field and temperature region where the second peak is detected. This study provides strong evidence that the second peak has its origin in changes of the elastic equilibrium properties of the vortex structures. | ||||
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| ISSN | 0031-9007 | ISBN | Medium | ||
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| Notes | ISI:000170212200049 | Approved | no | ||
| Call Number | BT @ hernan @ | Serial | 215 | ||
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| Author |
Correa, V.F.; Nieva, G.; Pastoriza, H.; de la Cruz, F. | ||||
| Title | The true pinning force range in Bi2Sr2CaCu2O8 single crystals at low temperatures | Type | Journal Article | ||
| Year | 2004 | Publication | Physica C | Abbreviated Journal | |
| Volume | 408-410 | Issue | Pages | 531-532 | |
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| Abstract | We study the effective profile of the pinning potential well in Bi$2$Sr$2$CaCu$_2$O8+δ single crystals using transverse ac magnetic susceptibility. The results show that the harmonic approximation for the potential well (linear regime) is valid up to vortex displacements $r\simeqξ$, where ξ, is the coherence length. In spite of this, it is necessary to induce displacements of the vortex structure much larger than ξ to depin it from its potential. This is shown to take place even in the single vortex limit. | ||||
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| Notes | Approved | no | |||
| Call Number | BT @ hernan @ correa04 | Serial | 9 | ||
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| Author |
Cotignola, J.M.; de la Cruz, F.; de la Cruz, M.E.; Platzeck, R.P. | ||||
| Title | Thermal Conductivity of Polycrystalline Zinc below 1 K | Type | Journal Article | ||
| Year | 1967 | Publication | Review of Scientific Instruments | Abbreviated Journal | |
| Volume | 38 | Issue | 1 | Pages | 87-92 |
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| Abstract | Measurements of the thermal conductivity of samples of polycrystalline zinc of thickness 0.1 mm have been carried out between 0.12 and 0.9°K in the normal as well as in the superconducting state to investigate the usefulness of zinc as a thermal switch. The conductivity in the normal state shows a linear dependence on temperature. In the superconducting state it shows a behavior typical of electronic conductivity down to the lowest temperature measured. By applying a magnetic field between 40 and 5000 Oe, magnetoresistivity was also investigated and a strong dependence of thermal conductivity on field was found. Electrical resistivity measurements were performed in magnetic fields at liquid 4He temperatures. The resistivity was found to be independent of temperature for fields up to 9000 Oe. The effect of solder joints using Cd, Sn, In, Zn, and Wood's metal was also investigated, Cd giving the least resistance. The measurements show that zinc should be a useful thermal switch for temperatures below 0.1 and 0.2°K, though effect of a magnetic field on the normal conductivity must be carefully considered. | ||||
| Address | Centro Atómico Bariloche – Instituto Balseiro | ||||
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| Publisher | AIP | Place of Publication | Editor | ||
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| Notes | Approved | no | |||
| Call Number | BT @ pedrazp @ cotignola:87 | Serial | 533 | ||
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| Author |
de la Cruz, F. | ||||
| Title | Structural relaxation: low temperature properties | Type | Conference Article | ||
| Year | 1984 | Publication | Abbreviated Journal | ||
| Volume | Issue | Pages | 269 | ||
| Keywords | ALLOY SYSTEMS, AMORPHOUS STATE, COPPER ALLOYS, SUPERCONDUCTING COMPOSITES, TEMPERATURE DEPENDENCE, ZIRCONIUM BASE ALLOYS | ||||
| Abstract | We discuss the changes in transport and superconducting properties of amorphous Zr70Cu30, induced by thermal relaxation The experimental results are used to investigate the relation between the microscopic parameters and the observed physical properties It is shown that the density of eletronic states determines the shift Tc as well as the variation of the electrical resistivity It is necessary to assume strong hybridization between s and d bands to understand the eletrodynamic response of the superconductor (Author) |
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| Publisher | Place of Publication | Brazil | Editor | ||
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| Series Editor | Series Title | Abbreviated Series Title | Proceedings of the Latin American Symposium of Physics of Amorphous Systems – v1 | ||
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| Notes | Approved | no | |||
| Call Number | BT @ pedrazp @ | Serial | 813 | ||
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| Author |
de la Cruz, F.; López, D.; Nieva, G. | ||||
| Title | Thermally induced change in the vortex dimensionality of YBa2Cu3O7 single crystals | Type | Journal Article | ||
| Year | 1994 | Publication | Philosophical Magazine Part B | Abbreviated Journal | Philos. Mag. B |
| Volume | 70 | Issue | 3 | Pages | 773 - 786 |
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| Abstract | Transport measurements in YBa2Cu3O7 single crystals using a modification of the d.c. flux transformer configuration are reported. We show that, for applied magnetic fields in the crystallographic c direction, the vortex correlation length in this direction is reduced to values smaller than the thickness of the sample. The reduction can be induced either by thermal disorder (linear response) or by flux cutting after the vortices reach a critical velocity (nonlinear response). The results show that, in the transition from a vortex-glass state to a vortex-liquid state, the vortices are effectively three dimensional in character. A two-dimensional regime is induced at higher temperatures well inside the reversibility region. | ||||
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| Notes | Approved | no | |||
| Call Number | BT @ gnieva @ | Serial | 456 | ||
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| Author |
de la Cruz, F.; Bressan, O.J. | ||||
| Title | Sensitive Hot Wire Level Detector for Cryogenic Liquids | Type | Journal Article | ||
| Year | 1969 | Publication | Review of Scientific Instruments | Abbreviated Journal | Rev. Sci. Instrum. |
| Volume | 40 | Issue | 3 | Pages | 483-486 |
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| Abstract | A very simple and highly sensitive ``hot wire'' type level detector to be used with cryogenic liquids is described. The hot filament is made of tungsten wire of about 4 µ diam. The tests on the sensor were made moving the filament in and out of the quiescent surfaces of liquid helium and nitrogen. The results showed 0.006 mm sensitivity in the determination of liquid helium level and 0.002 mm sensitivity in the case of liquid nitrogen level. The sensor is assembled in such a way that it can be used without special precautions during indefinite periods of time. For the case when the full capabilities of the sensor are not necessary, a simple circuit is presented. | ||||
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| Notes | Approved | no | |||
| Call Number | BT @ pedrazp @ | Serial | 549 | ||
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