Na0.5Bi0.5TiO3-Based Voltage-Tunable Materials

We have investigated the dielectric tunability of the Na_0.5Bi_0.5TiO₃ relaxor ferroelectric, modified with additions of Li_3xLa_(2/3)-xTiO₃ (0.03lesxges0.167) and NaTaO₃. These two additives have characteristics similar to incipient antiferroelectric and ferroelectric materials, respectively. The phase relations in the Na_0.5Bi_0.5TiO₃-Li_3xLa_(2/3)-xTiO₃ system were determined; however, this was made difficult by the slow kinetics and the thermodynamic instability of the compounds from the system. With an additives concentration of close to 10 mol% the material shows a relative dielectric tunability of up to 50%, moderate dielectric losses and a reduced temperature dependence of the dielectric constant, indicating that relaxor ferroelectrics might be promising materials for tunable applications.