Search

This paper reports the dielectric and glassy behavior of 70(Na0.5Bi0.5) TiO3-30SrTiO3 (NBT-30ST) lead-free perovskite relaxor. The temperature dependent dielectric data indicates that the material undergoes a diffuse phase transition at Tm (temperature corresponding to maximum dielectric constant) with diffuseness coefficient γ~2. The material also shows frequency dispersion around Tm with a high ΔTm (Tm,1MHz - Tm, 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 Tm 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 Tm has also been analyzed. [ABSTRACT FROM AUTHOR]

In this report, the glassy behavior of 60(Na0.5Bi0.5)TiO3-40SrTiO3 (NBT-40ST) lead-free perovskite relaxor was studied. The single phase ceramic sample was prepared with cubic symmetry by solid state reaction method. The temperature and frequency dependent dielectric data were analyzed in view point of relaxor and glassy behavior by employing various empirical models such as modified Curie-Weiss law, V-F law, Power law and Cheng's exponential relation. The diffuseness coefficient (γ~1.97) and the frequency dispersion of Tm (temperature corresponding to maximum dielectric constant) manifested strong relaxor behavior of NBT-40ST. The frequency dependent Tm analysis revealed greater interactions between the polar nano islands. Further, the study of dielectric behavior at much higher and lower temperature than Tm provided an idea about the production rate and concentration of these polar islands and distribution of freezing temperatures respectively [ABSTRACT FROM AUTHOR]