Dielectric Relaxation in (Sr_0.5Ca_0.5) Nb₂O₆ Solid-Solution

Controlling the cooling rate during calcinations and sintering temperature have prepared (Sr_0.5Ca_0.5) Nb₂O₆ by simple solid state reaction route. Material calcined at 1250°C and sintered at 1300°C gives pure phase in orthorhombic structure with lattice parameters a=7.4499A⁰ b=7.5717A⁰, c=20.2322A⁰ as revealed from X-ray diffraction study. Density of material is (>95%) that of theoretical value. The temperature dependent dielectric response shows a peak at temperature 325⁰C. Dielectric analysis reveals the effect of space charge polarization and or conducting ion motion. The dielectric dispersion observed in loss spectrum which may be due to the increase in ionic conductivity resulting from the disordering of the mobile cations in the oxygen octahedral skeleton. The Arrhenius nature of the loss peak is observed with estimated activation energy ≍ 0.16 eV.