Grain size effect on dielectric properties of submicron ranged BaTiO3 ceramics

BaTiO3 is one of the main multifunctional materials used for building passive and active components regarding present demands in microelectronics. A great concern is related to preserving high functional characteristics at... [ view full abstract ]

BaTiO₃ is one of the main multifunctional materials used for building passive and active components regarding present demands in microelectronics. A great concern is related to preserving high functional characteristics at specific grain size levels, in particular to nanoscale. Additionally, the role of intrinsic/extrinsic contributions to the exceptional dielectric and piezoelectric properties around the critical size of 1µm is still under discussion. The aim of the present work is to investigate in depth the functional properties of dense BaTiO₃ ceramics in the range of 1µm.

Fig. 1: Fracture micrographs of micron and submicron range BaTiO₃ dense ceramics.

Dense ceramics with various micron and submicron grain sizes were synthesized by spark plasma sintering (SPS) starting with BaTiO₃ fine powders, followed by various steps of subsequent thermal growth treatment. Phase purity and morphology of final ceramic samples, along with the dielectric functional properties have been investigated and addressed. Orthorhombic and tetragonal phase superposition with variable amounts of the two phases was observed, as a function of grain size. Permittivity values, the temperature evolution feature regarding the ferroelectric-paraelectric transition and tunability behavior show the typical dependence on the ceramic grain size with a maximum in the range of 1µm. The role of intrinsic/extrinsic contributions on this feature was discussed. 

Acknowledgements: This work was supported by the Romanian UEFISCDI PN-III-P4-ID-PCE-2016-0817 grant.