Enhanced giant dielectric response in Sr[(Fe_(0.5)Nb_(0.5))_(1-x)Ti_x]O_3 solid solutions

摘要

In the present work, the modified dielectric relaxations with extended giant dielectric constant step were observed in Sr[(Fe_(0.5)Nb_(0.5))_(1-x)Ti_x]O_3 solid solutions. The structure of Sr[Fe_(0.5)Nb_(0.5))_(1-x)Ti_x]O_3 solid solutions changed from orthorhombic to cubic with increasing x. A dielectric relaxation following Arrhenius law of Sr[(Fe_(0.5)Nb_(0.5))_(1-x)Ti_x]O_3 solid solutions was observed at lower temperature. The dielectric constant of Sr[(Fe_(0.5)Nb_(0.5))_(1-x)Ti_x]O_3 solid solutions decreased firstly and then increased with increasing SrTiO_3 content at 1 kHz, while the dielectric loss was suppressed monoton-ically. At x ＝ 0.8, the dielectric loss at room temperature and 1 kHz was 0.16 which was much smaller than that for x ＝ 0 (tan(δ ＝ 0.37), while the dielectric constant was increased to 6,815, and the temperature stability was also improved. This indicated that the dielectric characteristics of Sr(Fe_(0.5)Nb_(0.5))_(1-x)Ti_x]O_3 ceramics could be significantly improved by forming solid solution with SrTiO_3.