solid-state reaction, microstructure, impedance, conductivity
The polycrystalline Na2SmV5O15 (NSV), a new member of the tungsten bronze (TB) family, was prepared by a mixed-oxide technique. The room-temperature X-ray diffraction (XRD) confirmed the formation of single phase compound with orthorhombic crystal structure. The scanning electron microscopy (SEM) analysis indicated that the compound has homogeneous micrograph with a uniform distribution of small grains over the entire surface of the sample. The analysis of impedance spectra of NSV in a low-temperature range (-100 ℃ to 100 ℃) at different frequencies exhibited interesting electrical properties like the contribution of bulk effect in conduction process. The study of imaginary part of the impedance at different temperatures showed existence of relaxation peak with its shift towards higher frequency on increasing temperature. This suggested the presence of frequency and temperature dependent relaxation process in the material. The loss peak spectra were found to abide by Arrhenius law with small activation energy of 0.12 eV. The temperature dependence of AC and DC electrical conductivity (σAC and σDC) was also obtained.
Tsinghua University Press
P. S. DAS, P. K. CHAKRABORTY, Banarji BEHERA et al. Impedance spectroscopy study of Na2SmV5O15 ceramics. Journal of Advanced Ceramics 2014, 3(1): 1-6.