Revisiting the phase sequence and properties of K0.5Na0.5NbO3 ceramics sintered by different processes

In this work, we revisit the phase transition sequence and the effect of the sintering process on the structural, dielectric and polar properties of K0.5Na0.5NbO3 ceramics prepared by conventional sintering, spark plasma sintering and spark plasma texturing. Herein, comparative experimental study of the lattice dynamics, polar and dielectric properties is presented. We observe that the phase transition sequence includes an unreported structural and polar phase at low temperatures, independently on the processing method. Contrarily, we observe apparent changes of the stability temperature interval of the different phases. The dielectric strength and the emergence of a dielectric relaxation phenomenon are also noticeably dependent on the processing method, which can be understood as an effect of the different grain size. The results here reported clearly show the possibility to change physical properties following different sintering routes in order to improve device performance.

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