Synthesis of perovskite solid solution (NaxBa1-x)Ti(O1-x/3Clx/3)3 by solid-phase sintering method

Takesue, Naohisa*; Saito, Junichi  

Ferroelectrics are substances that exhibit energy storage, energy conversion between force, electricity, and heat, and polarization switching. These properties are widespread and deeply permeated into current technologies. Since our technologies will progress rapidly after the present, correspondingly ferroelectric properties need to be extensively explored and developed. We think that there are basically two kinds of conventional approaches to this goal; the one is synthesis by controlling chemical compositions of the substances, and the other the textures. We chose the former approach and employed template crystals with a perovskite-type structure. The reason for our choice is based on a fact that ferroelectricity emerges in many of the perovskite types, and also another one that a variety of ionic substitutes to the templates are available for both modeling and synthesis. Previously, our group performed molecular orbital calculations by using the template crystals. In the modeling process, being conscious of both environmental consideration and effective use of conserved natural resources, we decided to use the lead-free crystals including abundant elements. By the calculations, we predicted that a solid solution of barium titanate with marine substance sodium chloride, designated as (NaxBa1-x)Ti(O1-x/3Clx/3)3, possibly possesses the good properties. In order to verify our prediction, we synthesized samples of the predicted system by sintering, and by measuring their physical properties we investigated whether excellent ferroelectricity could be obtained. In this talk, we will mainly present the results of permittivities with respect to temperature.