Dielectric-spectroscopic and ac conductivity investigations on copper doped layered Na1.7K0.3Ti3O7 ceramics

Abstract

The dielectric losses in copper doped derivatives of layered Na1.7K0.3Ti3O7 ceramic are the cooperative contribution of electric conduction, dipole orientation, and space charge polarization. Moreover, copper doping decreases dielectric loss due to inhibition of domain wall motion. The room temperature electron paramagnetic resonance spectra reveal that copper occupies Ti4+ site with divalent oxidation state (Cu2+). For all compositions, ferroelectric phase transition having high transition temperature has been identified. It is also observed that less doping enhances electron hopping (polaron) conduction and impedes the interlayer ionic conduction. However, electron hopping conduction is dominant over lower temperature region, but as the temperature progresses, interlayer ionic conduction begins to prevail.