Crystal growth of layered perovskite Sr2Nb2O7 and Sr2Ta2O7 film by the sol-gel technique

Abstract

High dielectric and low loss capacitor thin films of Sr2Nb2O7 (SN), Sr2Ta2O7 (ST), and their solid solution Sr2(Nbx, Ta1−x)2O7 (SNT) were investigated using the sol-gel technique. The SN film grows with the (0n0) orientation in the case of heating at over 700 °C. Heat treatment at a lower temperature results in the polycrystal ST-type structure. The SNT at x < 50% also resulted in the ST type. The dielectric constant for the SN film was 45, within 10% variation at ±0.5 MV/cm. Dielectric loss (tan δ) was 0.3–0.5%. The small variation in dielectric constant and the paraelectricity with low loss are suitable for capacitor applications.