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We demonstrate that ferromagnets are effective artificial pinning centers for the enhancement of critical current (J/sub c/) in multifilamentary superconducting wires. We have analyzed theoretically the proximity effect due to the FM pins near the final size of several nanometers and determined that one should achieve a large pinning force by such centers(More)
We made thin film multilayers of NbTi and Nb (d/sub NbTi/=20 nm and d/sub Nb//spl ap/3-9 nm). Samples were characterized by electrical transport measurements between 4.2 K and T/sub c/, in magnetic fields up to 6 T. We present J/sub c/ as a function of the device geometry and orientation of the field. For some multilayers, J/sub c/ had a large peak whose(More)
Several small billets with NbTi binary and Nb 25 wt.% Ta 45 wt.% Ti ternary alloy filaments were made and fabricated into fine wire after subjecting the alloys to different treatment conditions. J/sub c/ results at 4.2 K and 1.8 K from binary and ternary materials, which were prepared under the identical conditions, are compared. The results of an alpha -Ti(More)
Low temperature superconductors containing artificial pinning centers (APC) in NbTi have shown critical current densities (below 4 T) substantially higher than metallurgically fabricated and optimized NbTi superconductors. Peak current densities are achieved when the pinning center spacing is matched to the spacing of the flux line lattice (FLL) at field of(More)
We made thin film multilayers of Nb/sub 0.37/Ti/sub 0.63//Nb and Nb/sub 0.37/Ti/sub 0.63//Ti (d/sub NiTi/=14-27 nm and d/sub N/=4-11 nm) to examine geometries and materials relevant to flux pinning in commercial NbTi conductors. Samples were characterized by transport measurements between 4.2 K and T/sub c/, in magnetic fields nearly parallel to the layers,(More)
The polyphenols are part of the composition of many foods, it is known the inhibitory effect of tea and coffee through the tannins on iron intestinal absorption; the "yerba mate" (Ilex Paraguarensis) is a beverage widely used in South America, that has a high content of a polyphenol named chlorogenic acid. The present work shows the effect of this substance(More)
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