Effects of MnO2 additive on the properties of PbZrO3–PbTiO3–PbCu1/4Nb3/4O3 ferroelectric ceramic system

The modifications (soft or hard doping) in lead zirconate titanate ceramics (PZT) lead to the creation of undesirable stoichiometric defects due to a lack of compensation in some of the components. Frequently, the complexed doping (with two or more elements) is used in order to obtain better results on PZT ceramics than that of single doping. We have investigated the PbZr0.50Ti0.44(Cu1/4Nb3/4)0.06(PZT–PCN), a ferroelectric ternary system where copper and niobium ions replace the Zr4+ or Ti4+ in B sites of the structure. The effects of MnO2 additions on the piezo and ferro-electric properties have been studied. We have analyzed the ac response of both undoped and doped PZT–PCN ceramic samples in a wide temperature range, especially above the Curie point. The MnO2 addition did not change the Curie temperature of the system and higher resistivity values have been observed in MnO2 doped ceramics which could be associated to the substitution of copper by manganese ions in the B-sites of the perovskite structure. At the same poling conditions, the electromechanical coupling factors were relatively lower in doped ceramics and the mechanical quality factor gave us an important difference between undoped and doped PZT–PCN system