Processing, texture quality, and piezoelectric properties of <001>_c textured (1-x)Pb(Mg_1/3Nb_2/3)TiO_3 - xPbTiO_3 ceramics

摘要

This paper describes the link between texture quality and electromechanical properties for <001>c textured, 0.03(Na_1/2Bi_1/2)TiO_3 - 0.97[0.715Pb(Mg_1/3Nb_2/3)TiO_3 - 0.285PbTiO_3] (0.03NBT-0.97[PMN-28.5PT]) ceramics with and without Mn-doping. Here, the subscript C denotes pseudocubic indices. Textured ceramics were prepared by templated grain growth of PMN-25PT on platelet-shaped 0.4(Na_1/2Bi_1/2)TiO_3-0.6PbTiO_3 (NBT-0.6PT) templates. Texture fractions of f= 0.92 (forundoped (l-x)Pb(Mg_1/3Nb_2/3)TiO_3-xPbTiO_3 (PMN-PT)) and f= 0.49 (for Mn-doped PMN-PT) were determined by fitting 002c XRD pole figures to the March-Dollase model, which was modified to account for symmetry-related 200_c and 020_c reflections. Using resonance methods, the elastic constants c_ij, S_ij, piezoelectric constants d_ij, e_ij, g_ij, h_ij, dielectric constants £y, and coupling coefficients ky of textured PMN-PT ceramics were characterized. It was found that the properties of textured PMN-PT approach the single crystal values along the texture axis (<001>_c, also the poling axis), but not in transverse directions. In particular, the elastic compliance s~E11 (perpendicular to <001>_c) approaches an average of the single crystal s~E11 and s~En(45°) coefficients, resulting in anomalous -s~E12/s~E11 ratios of — 0.01 and 0.04 in pure and Mn-doped textured PMN-PT, respectively. The 33-mode properties as measured by resonance-antiresonance methods were d_33 — 852 pC/N, k_33 = 0.83, e_33 = 3500, and mechanical quality factor Q_m = 94 for undoped textured ceramics and d_33 = 515, k_33 = 0.76, e_33 = 2200, and Q_m = 714 for Mn-doped textured ceramics.