Effect of Mn doping on the piezoelectric properties of 0.82Pb(Zr_(1/2)Ti_(1/2))O_3-0.03Pb(Mn_(1/3)Sb_(2/3))O_3-0.15Pb(Zn_(1/3)Nb_(2/3))O_3 ferroelectric ceramics

摘要

Mn-doped 0.82Pb(Zr_(1/2)Ti_(1/2))O_3-0.03Pb(Mn_(1/3)Sb_(2/3))O_3-0.15Pb(Zn_(1/3)Nb_(2/3))O_3 ceramics were prepared by conventional solid state reaction method. We investigated in detail the effects of adding MnO_2 on the structure and electrical properties of the PMS-PZN-PZT ceramics. With a small addition of MnO_2 ( ≤0.4 wt%), 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 MnO_2 prevented densification, causing a high porosity and small grain size. The doping of MnO_2 was found to transform the phase structure from tetragonal to rhombohcdral. The addition of MnO_2 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% MnO_2 exhibits excellent electrical properties with d_(33)=358 pC/N, K_P=0.61, Q_m = 1200, ε_r= 1232, tan δ=0.0041, and T_C=285 °C.