| Autor: |
Lashkarev, G. V., Radchenko, M. V., Baibara, A. E., Bugaiova, M. E., Petrosian, L. I., Dumond, Y., Story, T., Knoff, W., Nedelko, N., Ślawska-Waniewska, A., Foltyn, M., Stelmakh, Y. A., Krushynskaya, L. A. |
| Předmět: |
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| Zdroj: |
Low Temperature Physics; Feb2019, Vol. 45 Issue 2, p228-233, 6p, 3 Black and White Photographs, 1 Diagram, 3 Charts, 7 Graphs |
| Abstrakt: |
Magnetic nanocomposites (MNC), in which nanoparticles of ferromagnetic metals are distributed in wide-gap dielectric matrices (Al2O3 or SiO2), are prospective materials for electronics due to their amenability to technological control of the concentration and size of ferromagnetic nanoparticles. Co/Al2O3 and Co/SiO2 MNC layers with Co concentrations below the percolation threshold were deposited on polycor substrates using electron-beam deposition in a vacuum (EB-PVD). Scanning electron microscopy showed the presence of tightly packed Co grains of irregular shape with sizes of 5–50 nm in MNC. Low-temperature measurements of the magnetization for MNC Co/Al2O3 were made in the temperature range 4–300 K and magnetic fields up to 10 kOe. The 'magnetic exchange bias' has been detected, and it increases with a rise in Co concentration. By studying the electrical properties of the MNC Co/Al2O3 and Co/SiO2 in the temperature range of 77–280 K, the Mott type electron transport hopping mechanism was established. We first observed the effect of a giant positive thermoelectric power in a magnetic field in MNC Co/Al2O3 and the effect of a negative magnetothermoelectric power in a Co/SiO2. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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