Dielectric Relaxation of La3+-Modified Bi3TiNbO9 Aurivillius Phase Ceramics
Single Aurivillius phase Bi3−xLaxTiNbO9 (LBTN-x, x=0.00, 0.50, 0.75, and 1.00) ceramics were prepared by the conventional solid-state reaction method. When x≤0.50, the ceramics are normal ferroelectrics, while LBTN-0.75 and LBTN-1.00 showed typical relaxor behavior, which could probably be attributed to the disordering induced by the La3+ partly substituting for Bi3+ in Bi2O2 layers. The dielectric relaxation of LBTN-0.75 and LBTN-1.00 were fitted using the Vögel–Fulcher relationship, and the results suggest that both of them are analogous to a spin glass with thermally activated polarization fluctuations above a freezing temperature.
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