Lead-free potassium–bismuth titanate, K0.5Bi0.5TiO3 (KBT), ferroelectric ceramics were fabricated from the natural sintering of powders prepared by the thermal decomposition of adequate precursor solutions. Their crystal structure was determined by x-ray diffraction, and the temperature dependence of dielectric constants were measured. The results show that KBT may be a kind of order–disorder relaxor ferroelectric with a first-order phase transition below the temperature of dielectric constant maximum.

Ba0.96Sr0.04Zrx Y0.005Ti0.995–xO3–δ ceramics were prepared by conventional sintering. The dielectric properties and the Curie temperature of the ceramics were studied. The Ba0.96Sr0.04Zrx Y0.005Ti0.995–xO3–δ ceramics (x = 0.04) exhibit a giant dielectric constant (εr ∼ 105). The peak value of dielectric constant is ∼250,000 at 100 Hz and ∼70,000 at 1 MHz for Ba0.96Sr0.04Zrx Y0.005Ti0.995–xO3–δ ceramics (x = 0.04). The results show that Ba0.96Sr0.04Zrx Y0.005Ti0.995–xO3–δ (x = 0.04) ceramics are a promising candidate material for microelectronic applications. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)