Effect of Sm3+ doping on the structural and electrical conduction in PbTiO3 ceramics

In the present study, lead titanate doped with 1mol% Sm (Pb0.985Sm0.01TiO3 - PST) was synthesized by using planetary ball mill and solid-state reaction method. The PST ceramics were obtained by sintering at 800, 900, 1000 and 1100?C and their structure and electrical conductivity were investigated. The structural studies confirmed the presence of tetragonal phase and uniform fine grain structure of the prepared ceramics. It is observed that DC conductivity is directly proportional to temperature and follows the Arrhenius law. AC conductivity also increases with the increase in temperature for all sintered samples, but the ?AC vs. frequency curves tend to become flat, which shows the dominance of DC conductivity at higher temperatures in the low frequency region. The variation of density of states (DOS) at the Fermi level with temperature at different frequencies was investigated for the PST ceramics. The experimental investigation of DOS was compared with computational studies using material simulation software Quantum Espresso for optimized geometry. The studies of DC and AC conductivity confirmed migration between long range potential wells of the charge carriers and polaron induced charge-hopping mechanism in these ferroelectric ceramics.