Investigation of dielectric behavior of new Tb³⁺ doped BiFeO₃ nanocrystals synthesized via micro-emuslion route

摘要

The effect of Tb 3+ substitution at B site of nanoparticulateBiFeO 3 on various dielectric parameters was evaluated at room temperature in the frequency range of 1 MHz to 3 GHz. The value of x (i.e. Tb contents) was in the range of 0.00 to 0.02. Materials that have high dielectric constant cause resist the penetration of electromagnetic waves; therefore for devices working at high frequencies the low dielectric constant materials are preferred. The minimum dielectric constant (27.65) was observed at 3 GHz for Tb 0.008 Bi 0.992 FeO 3 , however the maximum dielectric constant (87.56) was observed for Tb 0.012 Bi 0.88 FeO 3 at ~ 1.00 MHz. Similar trends were observed for dielectric loss and tanδ values. In general for all compositions usually lo w dielectric constant, dielectric loss and tanδ were observed that suggest the applications of these materials for fabrications of devices that are required to operate at higher (GHz) frequencies range. Besides main types of dielectric parameters, the other parameters related to dielectric behavior such as ac-cond uctivity (σ ac ), the electrical modulus (M) etc were also evaluated. The ac-conductivity was found to increase with increased frequency and the maximum ac-conductivity was observed for Tb 0.012 Bi 0.88 FeO 3 nanoparticles. The mechanism of charge transport processes by electrical transport; ion dynamics and conductivity relaxation have also been explained in detail.