Effects of depressor addition on electrical properties of Pb(Mg1/3Nb2/3)O3–PbTiO3 dielectric ceramics

To develop inorganic dielectric materials for layer insulating materials with high dielectric constant and low dielectric loss of next-generation system-in-a-package, Pb(Mg1/3Nb2/3)O3–PbTiO3 (PMNT) and PMNT-Pb(Mg1/2W1/2)O3–Pb(Fe1/2 Ta1/2)O3 (PMNT–PMW–PFT; PMNT–PMWFT) ceramics were fabricated by the columbite precursor method. The addition of 1.0 mass% excess MgO to PMNT 94/6 was effective in restraining the formation of the pyrochlore phase and stabilizing the perovskite phase. When the mixing proportion (mol%) of PMNT 94/6/PMWFT 85/15 was 80/20, good dielectric properties with relative permittivity, εr of 4660 and dielectric loss, tanδ of 0.06% at 1 MHz were obtained. By varying the mixing proportion of PMW/PFT in PMWFT, which plays an important role of depressor to PMNT, 0.8PMNT 94/6·0.2PMWFT 70/30 ceramics having high εr of 5810, low tanδ of 0.07% at 1 MHz and their flat frequency characteristics were obtained by means of the effects of depressor addition to PMNT.