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Two-band effects in the transport properties of MgB2

Authors :: Pietro Manfrinetti
F. Napoli
A. Palenzona
M. Putti
Antonio Sergio Siri
E. Galleani
Valeria Braccini
I. Pallecchi
Source :: Superconductor science and technology, 16 (2003): 188–192. doi:10.1088/0953-2048/16/2/311, info:cnr-pdr/source/autori:M. Putti; V. Braccini; E. Galleani; I. Pallecchi; F. Napoli; P. Manfrinetti; A. Palenzona; A.S. Siri;/titolo:Two-band effects in transport properties of MgB2/doi:10.1088%2F0953-2048%2F16%2F2%2F311/rivista:Superconductor science and technology (Print)/anno:2003/pagina_da:188/pagina_a:192/intervallo_pagine:188–192/volume:16
Publication Year :: 2002
Publisher :: IOP Publishing, 2002.
Abstract: We present resistivity and thermal conductivity measurements on bulk samples, prepared either by a standard method or by a one-step technique. The latter samples, due to their high density and purity, show residual resistivity values as low as 0.5 mW cm and thermal conductivity values as high as 215 W/mK, higher than the single crystal ones. Thermal and electrical data of all the samples are analysed in the framework of the Bloch-Gruneisen equation giving reliable parameter values. In particular the temperature resitivity coefficient, obtained both from resistivity and thermal conductivity, in the dirty sample comes out ten time larger than in the clean ones. This result supports the hypothesis of ref. [1] that p and s bands conduct in parallel, prevailing p conduction in clean samples and s conduction in dirty samples .<br />Comment: 8 pages, 5 figures, Presented at the BOROMAG workshop, June 17-19 2002, Genoa, Italy