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

Abstract

Mn-doped 0.82Pb(Zr1/2Ti1/2)O3–0.03Pb(Mn1/3Sb2/3)O3–0.15Pb(Zn1/3Nb2/3)O3 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 (≤0.4wt%), the Mn ions were homogeneously dissolved in the PMS–PZN–PZT ceramic, leading to full densification when sintered at 1250°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 0.4wt%, remarkably improved the mechanical quality factor (Qm) of PMS–PZN–PZT ceramics as well as maintained high d33 and Kp 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 0.4wt%, the internal bias field was increased drastically. In addition, ambient temperature normalized strain d33⁎ and direct piezoelectric coefficient d33 were increased from 194pm/V and 132pC/N to 415pm/V and 358pC/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 0.4wt% MnO2 exhibits excellent electrical properties with d33=358pC/N, Kp=0.61, Qm=1200, εr=1232, tanδ=0.0041, and TC=285°C.