Phase transitional behavior in lead-free (1-x)(Li0.12Na0.88)NbO3-xBaTiO3 (0 ≤ x ≤ 0.40) ferroelectric ceramics

Abstract

ABSTRACT(1-x) Li0.12Na0.88NbO3-xBaTiO3 (0.0 ≤ x ≤ 0.40) ferroelectric ceramics were prepared using conventional ceramics route and their phase transitional behavior is investigated by using dielectric spectroscopy. The phase and microstructure analysis confirm a homogeneous solid solution and an existence of morphotropic phase boundary (MPB) composition near x = 10–12.5. A partial phase diagram has been proposed based on temperature-dependent dielectric permittivity ϵ′(T) studies. The observed diffused phase transition in ϵ′(T) was characterized by an acceptable and competent characterizing parameter (D), defined by Uchino et al. [J Am Ceram Soc 2010;93:4011], was measured and validated. Interestingly, a crossover from ferroelectric (FE) diffused phase transition (DPT) to relaxor ferroelectric (RFE) transition is found for the composition x ≥ 0.225. The ferroelectric-diffused phase transition (FE-DPT) is characterized by a frequency-independent temperature of dielectric maxima (Tm), while an RFE is found to have a frequency-dependent Tm.