Dielectric Tunability of (Sr0.8Pb0.2)TiO3-MgO Composites Under High Electric Fields

A family of ceramic composites fabricated from (Sr1-xPbx)TiO3 (SPT) and MgO show promise for room temperature electric field tunable ferroelectric applications. At the SPT (x = 0.2) composition room temperature is far above the Curie temperature and in a SPT-MgO (50:50 by weight) composite the dielectric response is almost anhysteretic. At this composition the composite is dielectrically robust and can be operated at field levels up to 175 kV/cm leading to tunability of 30% and a figure of merit, K-factor (tunability over tan delta) of more than 800. SPT-MgO composites with ionic polarization would be tuned by induced polarization under bias.