Role of dopant induced defects on the properties of Nd and Cr doped PZNT single crystals

The dielectric, ferroelectric and piezoelectric properties of rare-earth Nd-doped lead zinc niobate–lead titanate (Nd:PZNT) and transition metal Cr-doped lead zinc niobate–lead titanate (Cr:PZNT) single crystals have been investigated. Formation of pure perovskite phases was confirmed from powder X-ray diffraction. Lattice parameters have been obtained by Rietveld refinement. Both Nd and Cr doped crystals showed a diffuse phase transition and frequency dispersive phenomena supporting the enhancement in relaxor behavior. The variation in the values of dielectric constant (ɛr), AC conductivity and piezoelectric charge coefficient (d33) due to the creation of oxygen vacancies and lead vacancies as a result of doping is investigated in detail. Hysteresis behavior of the doped crystals is explained by considering the possible switching mechanism of domains and the formation of defect dipoles.