0000000000976176
AUTHOR
C. Cirillo
Superconducting nanowire quantum interference device based on Nb ultrathin films deposited on self-assembled porous Si templates
Magnetoresistance oscillations were observed on networks of superconducting ultrathin Nb nanowires presenting evidences of either thermal or quantum activated phase slips. The magnetic transport data, discussed in the framework of different scenarios, reveal that the system behaves coherently in the temperature range where the contribution of the fluctuations is important.
Interface Transparency of Nb/Pd Layered Systems
We have investigated, in the framework of proximity effect theory, the interface transparency T of superconducting/normal metal layered systems which consist of Nb and high paramagnetic Pd deposited by dc magnetron sputtering. The obtained T value is relatively high, as expected by theoretical arguments. This leads to a large value of the ratio $d_{s}^{cr}/ \xi_{s}$ although Pd does not exhibit any magnetic ordering.
Nonlinear current-voltage characteristics due to quantum tunneling of phase slips in superconducting Nb nanowire networks
We report on the transport properties of an array of N about 30 interconnected Nb nanowires, grown by sputtering on robust porous Si substrates. The analyzed system exhibits a broad resistive transition in zero magnetic field, H, and highly nonlinear V(I) characteristics as a function of H which can be both consistently described by quantum tunneling of phase slips.
Superconducting properties of Nb thin films deposited on porous silicon templates
Porous silicon, obtained by electrochemical etching, has been used as a substrate for the growth of nanoperforated Nb thin films. The films, deposited by UHV magnetron sputtering on the porous Si substrates, inherited their structure made of holes of 5 or 10 nm diameter and of 10 to 40 nm spacing, which provide an artificial pinning structure. The superconducting properties were investigated by transport measurements performed in the presence of magnetic field for different film thickness and substrates with different interpore spacing. Perpendicular upper critical fields measurements present peculiar features such as a change in the H_c2(T) curvature and oscillations in the field dependenc…
Intercultural education in italy. Cultural identity, educational emergency and teaching strategies: a mathematics laboratory
The research about the intercultural phenomenon in Italy increased with the growing phenomenon of migration, highlighting the problem of cultural diversity and social policies. "The encounter with the diversity should not be suffered, either tolerated, or rejected it should be accepted as survival strategy" (Callari Galli, 2000). This should go beyond the logic of the social emergency and the perception that people have of the problem. The school has, in this process, a key role. The goal of a good educa-tional project is to understand that the intercultural requires continual reference to the concrete experi-ences of the people Theoretical assumptions of the project are the concepts of “in…
Scelta varietale nei distretti tradizionali e nuovi areali
Tonda di Giffoni, Tonda Gentile Romana e Tonda Gentile Trilobata: il panorama varietale italiano è piuttosto ristretto e anche le nuove aree in cui il nocciolo è in espansione puntano sulle cultivar tradizionali più apprezzate dall’industria. Ma dopo l’esperienza positiva della Tonda Francescana® alcune isolate iniziative di miglioramento genetico puntano ad ampliare la piattaforma varietale e clonale
Controllable morphology of flux avalanches in microstructured superconductors
The morphology of abrupt bursts of magnetic flux into superconducting films with engineered periodic pinning centers (antidots) has been investigated. Guided flux avalanches of thermomagnetic origin develop a tree-like structure, with the main trunk perpendicular to the borders of the sample, while secondary branches follow well-defi ned directions determined by the geometrical details of the underlying periodic pinning landscape. Strikingly, we demonstrate that in a superconductor with relatively weak random pinning, the morphology of such flux avalanches can be fully controlled by proper combinations of lattice symmetry and antidot geometry. Moreover, the resulting flux patterns can be re…