Dielectric Properties and Glassy Behavior Study of 70(Na_(0.5)Bi0.5) TiO3-30SrTiO_3 Lead-Free Ceramic

摘要

This paper reports the dielectric and glassy behavior of 70(Na0.5Bi0.5) TiO_3-30SrTiO_3 (NBT-30ST) lead-free perovskite relaxor. The temperature dependent dielectric data indicates that the material undergoes a diffuse phase transition at T_m (temperature corresponding to maximum dielectric constant) with diffuseness coefficient γ～2. The material also shows frequency dispersion around T_m with a high AT_m (T_(m, 1MHz) - T_(m,0.1kHz))value of ～42. The above parameters manifest strong relaxor behavior of NBT-30ST. Moreover, the results are analyzed by employing empirical models such as V-F law, Power law to explore the glassy behavior associated with the system. The frequency dependent T_m analysis revealed greater interactions between the polar nano regions (PNRs). For further information on PNRs, the dielectric behavior at much higher and lower temperature than T_m has also been analyzed.