Transport phenomena in metal nanocomposites
| Autor: | M. V. Radchenko, G. V. Lashkarev, A. I. Dmitriev |
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| Rok vydání: | 2013 |
| Předmět: |
Condensed Matter::Materials Science
Materials science Ferromagnetism Condensed matter physics Spintronics Electrical resistivity and conductivity Percolation Seebeck coefficient Percolation threshold Dielectric Atmospheric temperature range Condensed Matter Physics Electronic Optical and Magnetic Materials |
| Zdroj: | Physics of the Solid State. 55:687-691 |
| ISSN: | 1090-6460 1063-7834 |
| Popis: | Ferromagnetic nanocomposites are the special case of metal composites; they are of practical interest for spintronics. Temperature dependences of resistivity ρ(T) and thermoelectric power α(T) of ferromagnetic nanocomposites with the composition Cox(Al2O3)100 − x (36.6 ≤ x ≤ 52.5 at %) are investigated near the percolation threshold (xp ≈ 43.3 at %) in a temperature range of 77–300 K. Sizes of Co nanoparticles are no larger than 25 nm. Specific features are observed in the dependences α(T) in the form of a kink at Tb ≈ 170 K. The analysis of the structural and electrical schematics as well as energy diagrams of percolation channels of electrons shows that only the diffusion thermoelectric power appears in Co nanoparticles, at which α(T) is the linear function. No mechanisms of the thermoelectric power caused by nanosizes of Co particles or by electron tunneling between them are found. The kink of the α(T) linear dependence is explained by the existence of the oxide shell of Co nanoparticles. It is assumed that the temperature dependences of energy barriers of oxide shells of metal nanoparticles (including ferromagnetic ones) in oxygen-containing dielectric matrices determine the features of α(T) and ρ(T) dependences of such nanocomposites. |
| Databáze: | OpenAIRE |
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