Dielectric and ferroelectric properties of Ba_1−xSr_xTiO₃ ceramics: effects of grain size and ferroelectric domain

Abstract

Abstract

Ba_1−xSr_xTiO₃ (x = 0·3, 0·35) ceramics are fabricated by spark plasma sintering (SPS) technique and conventional sintering (CS) route. Their microstructures are determined together with the dielectric and ferroelectric properties. The grain sizes of SPS samples are smaller than those of CS. The differential scanning calorimetry data show that almost no latent heat associated with phase transition can be detected in the SPS sintered ceramics. Raman spectroscopy analysis suggests that the tetragonal phase increases with increasing the grain size, and the higher content of tetragonal phase leads the superior dielectric properties in CS sintered samples. Transmission electron microscopy analysis indicates that domain structure heavily relies on the grain size of ceramics. The poor ferroelectric properties of SPS ceramics are originated from the incomplete development of the tetragonal structure.

Keywords:

• Ba_1−xSr_xTiO₃
• Spark plasma sintering
• Grain size
• Ferroelectric domain

This work was supported by the Natural Science Foundation of China under grant nos. 51272233 and 50832005 and by the National Basic Research Program of China under grant no. 2009CB623302.