Low temperature magneto-conductivity properties of micro-sized Ag/HD-PE metal/polymers |
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Authors: | L Lanotte G Ausanio V Iannotti G Pepe G Carotenuto L Nicolais |
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Institution: | (1) INFM - Università di Napoli Federico II, Dip. Scienze Fisiche, P.le Tecchio n. 80, 80125, Napoli, Italy, IT;(2) Università di Napoli Federico II, Dip. di Ing. dei Materiali e della Produzione, P.le Tecchio n. 80, 80125, Napoli, Italy, IT |
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Abstract: | A composite material of a polyethylene matrix filled by a fine silver powder was prepared with different Ag contents and physical
behaviours ranging from insulator to conductor. Ac differential magnetic susceptibility χ measurements show the samples are
paramagnetic up to an Ag concentration of ∼65%. At low temperatures the composite is spin-glass type, whereas the transition
from insulator to conductor corresponds to an abatement of χ at zero magnetizing field. Magneto-conductivity effects have
been observed in resistivity measurements at low temperatures. They can be explained in terms of an effective exchange electronic
scattering mechanism between the conduction electrons and the diluted magnetic moments arising from unpaired electron spins
of boundary silver particles. Moreover, the presence of a broad minimum in the resistivity curve at T = ∼ 20 K, observed in samples with an Ag concentration just above the percolation threshold, addresses to possible interference
effects similar to those reported in disordered materials.
Received 17 October 2000 and Received in final form 22 February 2001 |
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Keywords: | PACS 72 80 -r Conductivity of specific materials – 72 80 Le Polymers organic compounds (including organic semiconductors) – 81 05 Lg Polymers and plastics rubber synthetic and natural fibers organometallic and organic materials |
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