Abstract
This work presents some electrical properties based on impedance measurements as well as the dielectric constants and electric modulus. In order to study the electrical conductivity and dielectric properties of PrNaMnMoO6, complex impedance spectroscopy techniques were carried out in the frequency range 200 Hz-5 MHz at various temperatures (409-457 K). The complex impedance diagram at different temperatures showed a single semicircle, implying that the response originated from a single capacitive element corresponding to the grains. AC and dc conductivities were studied to explore the mechanisms of conduction. It can be seen from the experimental data that the AC conductivity of this compound is proportional to omega(s)(s<1), and the value of s is to be temperature-dependent, which has a tendency to decrease in temperature. Activation energy values deduced from both dc conductivity and hopping frequency are in the order of E-a=0.32 eV and E-a=0.29 eV, respectively. The two values E-a=0.32 eV and E-a=0.29 eV of activation energies obtained from the hopping frequency and equivalent circuit confirms that the transport is through an ion hopping mechanism dominated by the motion of the Na+ ion in the structure of the investigated material. In general, the size of the A ion influences the crystal symmetry significantly, while that of the B ion does not change the symmetry, but changes the lattice volume proportionally. The influence of the nature of the divalent A-site cations on the dielectric properties was evaluated by resistivity measurements in the frequency range. It is found that relative permittivity and dielectric loss regularly change with A cation size.