Effect of Mn doping on the piezoelectric properties of 0.82Pb(Zr1/2Ti1/2)O3-0.03Pb(Mn1/3Sb2/3)O3-0.15Pb(Zn1/3Nb2/3)O3 ferroelectric ceramics

Mn-doped 0.82Pb(Zr1/2Ti1/2)O-3-0.03Pb(Mn1/3Sb2/3)O-3-0.15Pb(Zn1/3Nb2/3)O-3 ceramics were prepared by conventional solid state reaction method. We investigated in detail the effects of adding MnO2 on the structure and electrical properties of the PMS-PZN-PZT ceramics. With a small addition of MnO2 ( <= 0.4 wt%), the Mn ions were homogeneously dissolved in the PMS PZN PZT ceramic, leading to full densification when sintered at 1250 degrees C. However, further addition of MnO2 prevented densification, causing a high porosity and small grain size. The doping of MnO2 was found to transform the phase structure from tetragonal to rhombohedral. The addition of MnO2 up to a maximum of 0.4 wt%, remarkably improved the mechanical quality factor (Q(m)) of PMS-PZN-PZT ceramics as well as maintained high d(33) and K-p values. The piezoelectric and ferroelectric properties of these samples were also investigated through measurements of the ferroelectric hysteresis loops and electric field induced strain curves. With increasing Mn content from 0 to 0.4 wt%, the internal bias field was increased drastically. In addition, ambient temperature normalized strain d(33)(*) and direct piezoelectric coefficient d(33) were increased from 194 pm/V and 132 pC/N to 415 pm/V and 358 pC/N, respectively. The origin of the internal bias field is attributed to the defect dipoles, which were formed by the acceptor impurities and oxygen vacancies. PMS-PZN-PZT doped with 0.4 wt% MnO2 exhibits excellent electrical properties with d(33)=358 pC/N, K-p=0.61,K- Q(m)=1200, epsilon r=1232, tan delta=0.0041, and T-c=285 degrees C. (C) 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved.