Synthesis, structural and electrical properties of NaTaO:Cu.

This work describes the synthesis and characterization of copper doped sodium tantalate obtained by ultrasonically route with immersed sonotrode in the reaction medium followed by heat treatment at 600 °C, in air for 6 h. The as-obtained NaTaO:Cu material crystallizes in the orthorhombic structure with C m c 2(36) space group and the average size of crystallites was found to be 70 nm. Analysis by scanning electron microscopy with energy dispersive X-ray spectroscopy showed that the compound is chemically homogeneous and strongly agglomerated, and the value of the optical band gap E was 3.61 eV. Based on the complex impedance measurements, over the frequency range 50 Hz-2 MHz and different temperatures situated between 30 and 120 °C, the frequency and temperature dependence of the electrical conductivity of the sample was obtained. Activation energy for conduction E , was determined from measurements of dc-conductivity and increases linearly with the increases in temperature between 175 and 215 meV. [ABSTRACT FROM AUTHOR]