LAUSR

In this work, we report the effect of Ti-doping on the structural, electrical and dielectric properties of Pr0.75Bi0.05Sr0.1Ba0.1Mn1−xTixO3 (x = 0 and 0.04) manganites synthesized by sol–gel route. X-ray structural analysis using Rietveld refinement technique reveals that our samples are single phase and crystallize in the orthorhombic system with Pbnm space group. These structures were characterized by impedance spectroscopy in the frequency range from 40 to 1 MHz and temperatures between 80 and 400 K. DC conductivity analysis shows that our samples disclose a semiconductor behaviour with a semiconductor–metal transition temperature TMS at 380 and 360 K for x = 0 and 0.04 respectively. This result shows that the TMS temperature can be controlled by varying the titanium content. AC conductivity (σAC) results show a considerable sensitivity to both temperature and frequency. The impedance plots were well described by an equivalent circuit model taking into account the contributions of semiconductor grains and insulating grain boundaries in the conduction mechanism. Furthermore, a non-Debye type of relaxation in our compounds was confirmed. In addition, we have demonstrated that the dielectric relaxation is hidden by the DC conduction mechanism.