Dielectric properties of sodium and neodymium substitute to A-Site SrBi4Ti4O15 ceramics

Polycrystalline ceramics, SrBi4Ti4O15 (SBT) and Sr0.2Na0.4Nd0.4Bi4Ti4O15 (SNBT), were synthesized by solid state sintering method using planetary ball mill. The stoichiometric powders were ground for 10 hours. Single phase formation was established from the XRD results. The highest peak (119) was seen at 30°. X-ray diffraction results indicated decreased cell volume and orthorhombic distortion with the substitution of Na+ and Nd3+ in place of Sr2+. The lattice parameters were measured using Unitcell software. Grain size as well as grains random orientation was observed from scanning electron microscope results. Dielectric properties were measured using Novo control dielectric analyzer, from room temperature to 1200 °C at frequencies 1 kHz, 10 kHz, 50 kHz, 100 kHz, 500 kHz, and 1 MHz. The dielectric constant and loss decreased whereas the Curie temperature increased when Na+ and Nd3+ were substituted to A- site in SBT. This ceramic has enhanced thermal stability thus making this ceramic appropriate for sensor applications at high temperatures.