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E. Paumier

Bio: E. Paumier is an academic researcher. The author has contributed to research in topics: Irradiation & Flux pumping. The author has an hindex of 2, co-authored 2 publications receiving 39 citations.

Papers
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Journal ArticleDOI
TL;DR: In this paper, single crystals of YBa2Cu3O7−δ were irradiated at 95 K by 5.6 GeV Xe ions and the evolutions of the superconducting resistive curves were determined in situ as a function of ion fluences.
Abstract: Single crystals of YBa2Cu3O7−δ were irradiated at 95 K by 5.6 GeV Xe ions and the evolutions of the superconducting resistive curves - measured parallel and perpendicular to the c axis - were determined in situ as a function of ion fluences. We find that ϱc and ϱab increase linearly with the fluence and even tend to saturate for the highest fluences. This behaviour strongly differs from that found for sintered samples irradiated under the same conditions for which a quasi-exponential increase of resistance was observed. Nevertheless our results confirm that energy deposition by electronic excitation plays a role in defect creation as previously reported in Xe irradiated sintered samples.

34 citations

Journal ArticleDOI
TL;DR: In this paper, the effects of high energy ions in superconductor YBa2Cu3O7 were investigated and the results showed that high energy ion irradiation effects can be significant.
Abstract: (1993). Irradiation effects of high energy ions in superconductor YBa2Cu3O7. Radiation Effects and Defects in Solids: Vol. 126, No. 1-4, pp. 155-158.

5 citations


Cited by
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Journal ArticleDOI
L Civale1
TL;DR: In this article, the influence of the angular dispersion (splay) of the tracks on vortex pinning and creep is discussed, and measurements of the temperature, field and defect density dependence of the persistent currents and their time relaxation in YBCO are presented.
Abstract: Columnar defects introduced by irradiation with very energetic heavy ions are the most effective pinning centres for flux lines in high-temperature superconductors. This correlated disorder generates large increases in the critical current densities and expansion of the irreversible regime in and the various Bi- and Tl-based compounds. In single crystals and thin films, the pinning enhancement is strongly angular-dependent, and maximizes when the applied magnetic field is parallel to the amorphous latent tracks. In contrast, in the much more anisotropic Bi- and Tl- based materials this unidirectional anisotropy is very small due to the quasi two-dimensional character of the vortices. Some of the extensive experimental studies on this topic are reviewed. Measurements of the temperature, field and defect density dependence of the persistent currents and their time relaxation in YBCO are presented. The analysis of these results based on recent theoretical models permits the identification of various pinning and creep regimes. Studies in other compounds, including technologically relevant Bi-based tapes, are summarized. The influence of the angular dispersion (splay) of the tracks on vortex pinning and creep is discussed.

183 citations

Journal ArticleDOI
TL;DR: In this paper, a Monte Carlo method is used to describe event by event the interactions of the projectile with the target electrons as well as the evolution of the electronic subsystem of the target.
Abstract: In this paper the swift heavy ion interactions with condensed matter are studied from the point of view of the modifications induced in the electronic subsystem of the target. A Monte Carlo method is used to describe event by event the interactions of the projectile with the target electrons as well as the evolution of the electronic subsystem. The validity of the method and the results are discussed. This detailed picture of the excited target could be used for further explanations and calculations of the damage creation by electronic excitation. We have focused our attention on two materials whose electronic properties are different: graphite and quartz. For both materials a quantitative analysis of the energy deposition mechanism is given.

128 citations

Journal ArticleDOI
TL;DR: In this article, the state of the art of nanometric amorphization of oxide materials induced by dense electronic excitation following the slowing down of a swift heavy ion was presented and the correlation between the nanometeric observations and the chemical and physical properties of the irradiated materials was described.
Abstract: The state of art of nanometric amorphisation of oxide materials induced by dense electronic excitation following the slowing down of swift heavy ion will be presented. After a description of experimental observations and quantifications of the nanometric amorphisation, it will be shown that the electronic collisions regime is very efficient to induce the phase transformations. The correlation between the nanometeric observations and the chemical and physical properties of the irradiated materials will be described.

64 citations

Journal ArticleDOI
E. H. Brandt1
01 Apr 1992-EPL
TL;DR: In type-II superconductors the pinning force which determines the critical current density Jc, and the pining energy U which determines thermally activated depinning, in principle are different quantities.
Abstract: In type-II superconductors the pinning force which determines the critical current density Jc, and the pinning energy U which determines thermally activated depinning, in principle are different quantities. Long pinning channels generated by high-energy heavy-ion irradiation, in YBCO can enhance both Jc and U, but in the strongly layered BSCCO they may enhance Jc without enhancing U, since the pancake vortices in the layers depin individually. This is the reason why in BSCCO flux creep is large down to rather low temperatures.

41 citations

Journal ArticleDOI
TL;DR: In this article, Tl-based superconducting copper oxides were irradiated at 140 K by 3.6 GeV Xe ions and the resistance measured in situ as a function of the fluence.
Abstract: Tl-based superconducting copper oxides Tl 2 Ba 2 CaCu 2 O 8 , TlBa 2 Ca 2 Cu 3 O 9 and Tl 2 Ba 2 Ca 2 Cu 3 O 10 were irradiated at 140 K by 3.6 GeV Xe ions and the resistance measured in situ as a function of the fluence. The results confirm that electronic stopping of GeV heavy ions plays a major role in the defect creation mechanism. Critical current densities were obtained from magnetization measurements on samples irradiated by 5.8 GeV Xe ions at fluences up to 2x10 12 cm -2 and magnetic field orientations parallel and normal to the heavy ions tracks. Large enhancements of flux pinning and J c are observed, in particular at low fluences, without significant change of the T c 's.

36 citations