Effects of Manganese Addition on Piezoelectric Properties of Pb(Zr0.5Ti0.5)O3

The effects of MnO2 addition on k 31 and Q m were investigated for Pb(Zr0.5Ti0.5)O3(PZT). The MnO2 addition increased Q m and k 31 in a low poling field. This result indicated that Mn-doped PZT possessed properties of `soft' and `hard' piezoelectrics simultaneously. Electron spin resonance measurement indicated that Mn2+, Mn3+ and Mn4+ coexisted in PZT. The tetragonality of the PZT lattice and the Curie temperature decreased with MnO2 content. From these results, it was found that the increase in k 31 of Mn-doped PZT was due to the change of the crystal structure toward a cubic system, and the increase in Q m to Mn2+ and Mn3+ ions working as acceptor dopants. The characteristic feature of Mn is that its addition to PZT decreases tetragonality, and various valence states coexist in proper ratio in Mn-doped PZT sintered in atmosphere.