The effect of sintering temperature on nonlinearity coefficient of ZnO-Bi2O3 nanocomposites

M. Zahraee (1), M. Mozaffari (1, 2), S. M. H. Feiz (2), E. Borz- Abadi (2)

1 Department of Physics, Razi University, Kermanshah, Iran.
2 Department of Physics, University of Isfahan, Isfahan, Iran.

Abstract
In this work ZnO-Bi2O3 nanocomposites with different mole percent (0.25, 1 and 1.5) of Bi2O3 were prepared by high energy ball milling (HEBM), using a SPEX mill. The milled powders were then pressed uniaxially in the form of cylinders with 15 mm in diameter and about 2 mm in thickness. The compacted disks were sintered at temperatures 750, 850 and 950 °C and then electrodes were applied, using silver paste. Room temperature E-J curves of the samples were obtained and their nonlinearity coefficient and resistivity were calculated. The coefficient was optimized to obtain its maximum. The results show that nonlinearity parameter and dc resistivity depend on the sample composition and its sintering temperature. A maximum nonlinearity coefficient of 13.5 was obtained for the sample sintered at 850 °C, which is higher than that of a sample made by micro sized ZnO. Also the results show that samples with mole percent of 0.25 and those sintered at 750 °C don't show nonlinearity behavior, which is a result of absence of two-phases structure.