Papers by Keyword: Electric Transport

Abstract: The electric resistivity, Seebeck coefficients and power factors of Y_1-xEu_xBaCo₄O_7+δ (x = 0.0, 0.05, 0.1, 0.2) ceramics were investigated from 400K to 1000K. The results show that the presence of Eu decreases electrical resistivity, and has little effect on Seebeck coefficients of the samples. The activation energy of conductivity is calculated by the Arrhenius plots in the semiconductive region. According to power factors, the optimum Eu substitution amount is x = 0.1, which results in a higher power factor of 67.5 μWm^-1K^-2 at 1000K, 30% higher than unmodified sample YBaCo₄O_7+δ.

Abstract: Using pulsed laser deposition we prepared Fex-C1-x films on Si (100) substrates. We show that the lightly Fe-doped amorphous carbon films on Si substrate have large MR at room temperature. At T=300K and B=5T a large positive MR of 138% was found in Fe0.011-C0.989 film. Furthermore, we find that when temperature T<258K, the MR of Fe0.011-C0.989 film on Si substrate is negative and when 258K

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