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| Format: | Artículo científico |
| Language: | en |
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Sociedade Brasileira de Física
2004
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| Online Access: | https://www.redalyc.org/articulo.oa?id=46434607 |
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Table of Contents:
- Magnetic and transport properties of PdH: intriguing superconductive observations Paolo Tripodi Daniele Di Gioacchino Jenny Darja Vinko Física, Astronomía y Matemáticas Since the discovery of superconductivity in palladium-hydrogen (PdH) and its isotopes (D,T) at low temperature,several efforts have been made to study the properties of this system. Superconductivity of PdH system hasbeen initially claimed by resistance drop versus temperature and then confirmed by dc magnetic susceptibilitymeasurements. These studies have shown that the critical transition temperature is a function of the hydrogenconcentration x in the PdHx system. In all these experiments, the highest concentration x of hydrogen in palladiumwas lower than the unit. In the last decade we defined a room temperature and room pressure technique toload hydrogen and its isotopes into palladium at levels higher than unit, using electrochemical set-up, followedby a stabilization process to maintain the hydrogen concentration in palladium lattice stable. In the meanwhile,several measurements of resistance versus temperature have been performed. These measurements have shownseveral resistive drops in the range of [18K< Tc < 273K] similar to the results presented in literature, when thesuperconducting phase has been discovered. Moreover, on PdH wires 6cm long the current-voltage characteristicwith a current density greater than 6 ¤ 104 Acm¡2 has been measured at liquid nitrogen temperature. Thesemeasurements have the same behavior as superconducting I-V characteristic with sample resistivity, at 77K, oftwo orders of magnitude lower than copper or silver at the same temperature. The measurements of first andthird harmonic of ac magnetic susceptibility in PdHx system have been performed. These represent a goodtool to understand the vortex dynamics, since the superconducting response is strongly non-linear. Clear acsusceptibility signals confirming the literature data at low temperature (9K) and new significant signals at hightemperature (263K) have been detected. A phenomenological approach to describe the resistance behaviour ofPdH versus stoichiometry x at room temperature has been developed. The value x=1.6 to achieve a macroscopicsuperconducting state in PdHx has been predicted. 2004 artículo científico 0103-9733 https://www.redalyc.org/articulo.oa?id=46434607 en http://www.redalyc.org/revista.oa?id=464 Brazilian Journal of Physics application/pdf Sociedade Brasileira de Física Brazilian Journal of Physics (Brasil) Num.3B Vol.34