0000000000280169
AUTHOR
Paolo Mele
Origin of the fast magnetization relaxation at low temperatures in HTS with strong pinning
The temperature T variation of the normalized magnetization relaxation rate S in high-temperature superconductors (HTS) with strong vortex pinning exhibits a maximum in the low-T range. This was reported for various HTS, and the origin of the faster relaxation at low T appearing in standard magnetization relaxation measurements was usually related to specific pinning properties of the investigated specimens. Since the observed behaviour seems to be characteristic to all HTS with enhanced pinning (generated by random and/or correlated disorder), we show that the S(T) maximum can be explained in terms of classic collective vortex creep. The influence of thermo-magnetic instabilities in the lo…
Magnetization relaxation in YBCO films with improved supercurrent transport properties
The relaxation of the irreversible magnetization in optimally doped YBCO films with natural and artificial pinning centres was measured in zero-field cooling conditions using SQUID magnetometry. The external magnetic field H was oriented along the c axis. An appropriate method for the determination of the characteristic vortex pinning energy from the normalized vortex-creep activation energy is discussed. This is based on the existence of a crossover elastic (collective) vortex creep at low temperatures T – plastic vortex creep at high T, caused by the T dependent macroscopic currents induced in the sample during magnetization measurements.
Inhibition of the detrimental double vortex-kink formation in thick YBa2Cu3O7films with BaZrO3nanorods
We investigated the temperature (T) variation of the normalized magnetization relaxation rate S and of the corresponding normalized vortex-creep activation energy U* = T/S for YBa2Cu3O7 films containing BaZrO3 nanorods, with the external magnetic field H oriented perpendicular to the film surface. It was found that by increasing the film thickness and using nanodot decorated substrates the high-T S(T) maximum appearing at low H is substituted by a minimum in S(T). As revealed by the analysis of the current density dependence of U*, this behaviour is due to the inhibition of vortex excitations involving double vortex-kinks and superkinks formation in the investigated thick films, owing to th…
Sull’importanza di essere estremi : esercizi di utopie praticabili
"Per Fare un Tavolo. Arte e territorio" è un evento ideato da Bianco-Valente e Pasquale Campanella nell'ambito del Padiglione Italia alla 17ª Mostra Internazionale di Architettura della Biennale di Venezia e parte integrante del progetto A Cielo Aperto, le cui attività sono sostenute dall'Associazione Culturale Vincenzo De Luca, nel Comune di Latronico. I contributi presenti nella pubblicazione provengono da personalità afferenti a diversi ambiti disciplinari, sono un approfondimento sulle tematiche delle aree interne e degli sviluppi delle pratiche artistiche legate al territorio, per definire il ruolo "pubblico" dell'arte, degli artisti e delle comunità.