Preparation and Ferroelectric Properties of SBN:50 Ceramics

Stoichiometric quantities of AR‐grade chemicals, e.g., Ba(NO 3 ) 2 , Sr(NO 3 ) 2 , and Nb 2 O 5 , were used to synthesize Sr 0.5 Ba 0.5 Nb 2 O 6 (SBN:50) by the solid‐state reaction route. The reaction mixture was characterized by DTA/TG/DTG to locate the formation temperature of SBN:50. X‐ray diffrction was used to identify the major and any additional phases formed in the calcined as well as sintered materials. The materials were further characterized by electrical measurements, the temperature dependence of the dielectric constant (ɛ) and the loss (tan δ), FE hysteresis‐loop parameters ( P s and E c ), and room‐temperature dc resistivity. SBN:50 exhibited a broad maximum of ɛ in the temperature range 65° to 95°C. Moreover, the FE hysteresis loop persisted even at 130°C, which is much higher than the Curie range determined from an ɛ vs T plot. Microstructural photographs revealed varied grain‐size distribution between 5 and 20 μm. The presence of residual porosity (∼ 95% dense) resulted in opaque compacts.