Processing, texture quality, and piezoelectric properties of <001>_C textured (1-x)Pb(Mg_1/3Nb_2/3)TiO₃ - xPbTiO₃ ceramics

This paper describes the link between texture quality and electromechanical properties for <001>_C textured, 0.03(Na_1/2Bi_1/2)TiO₃ - 0.97[0.715Pb(Mg_1/3Nb_2/3)TiO₃ - 0.285PbTiO₃] (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)TiO₃-0.6PbTiO₃ (NBT-0.6PT) templates. Texture fractions of f = 0.92 (for undoped (1-x)Pb(Mg_1/3Nb_2/3)TiO₃-xPbTiO₃ (PMN-PT)) and f = 0.49 (for Mn-doped PMN-PT) were determined by fitting 002_C 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 ɛ_ij, and coupling coefficients k_ij 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^E₁₁(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 d₃₃ = 852 pC/N, k₃₃ = 0.83, ε₃₃ = 3500, and mechanical quality factor Q_m = 94 for undoped textured ceramics and d₃₃ = 515, k₃₃ = 0.76, ε₃₃ = 2200, and Q_m = 714 for Mn-doped textured ceramics.