AC Conductivity and Dielectric Relaxation Behavior of Sol-gel BaxSr1-xTiO3 Thin Films

BaxSr1-xTiO3 sol-gel thin films with x=0.5, 0.7 and 0.8 have been fabricated as Al/BST/Pt capacitor. The AC conductivity and dielectric properties over a frequency rang of 10 Hz and 1 MHz have been studied in order to explore the ion dynamics and relaxation mechanisms in the films. The frequency dependent conductivity plots show three regions of conduction processes. Dielectric results show that epsilon' at low frequencies increases as Sr content decreases, whereas at high frequencies, it shows opposite variation, which is attributed to the dipole dynamics. The electric modulus plots reveal the relaxation peaks which are not observed in the epsilon '' plots and the contribution of the grains, grain boundaries and electrode to the relaxation mechanisms.