Effect of grain size on dielectric and ferroelectric properties of nanostructured Ba0.8Sr0.2TiO3 ceramics

Abstract

Barium strontium titanate (Ba 0.8 Sr 0.2 TiO 3 , BST) nanocrystalline ceramics have been synthesized by high energy ball milling. As the sintering temperature increases from 1200 ℃ to 1350 ℃, the average grain size of BST ceramics increases from 86 nm to 123 nm. The X-ray diffraction (XRD) studies show that these ceramics are tetragonal. The phase and grain size of the sintered pellets have been estimated from the XRD patterns, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images. The effect of grain size on dielectric and ferroelectric properties is studied. The dielectric and piezoelectric parameters are greatly improved at room temperature with increase in grain size. The Curie transition temperature is found to shift slightly towards higher temperatures as the grain increases from 86 nm to 123 nm. The coercive field decreases and the remnant polarization and spontaneous polarization increase as the grain size of BST nano ceramics increases. These ceramics are promising materials for tunable capacitor device applications.

Intrinsic pyroelectric properties of thick, coarse grained Ba 1−x Sr x TiO 3 ceramics

“…In the present case, the remnant polarization obtained from the dynamic hysteresis loop presented in the supplemental material for undoped BaTiO 3 ceramic is of about 11.5 μCcm -2 , which is higher than previous reports showing values that spread between 0.005 μC/cm 2 and 7.5 μC/cm 2 [45,[48][49][50][51]. Also, the remnant polarization for the other BST ceramics is, in general, higher than previous reports [52,53]. The present results are comparable to those recently reported for ceramics obtained by spark plasma sintering [54].…”

Influences of Liquid‐Phase Sintering on Structure, Grain Growth, and Dielectric Behavior of PbZr0.52Ti0.48O3 Ceramics

“…As the dielectric properties of bulk ferroelectric materials result from the combination of the intrinsic response of the system (i.e., the appropriate directional average of the response expected from a single‐domain crystal with well‐defined boundary conditions) and extrinsic effects, like those associated with domain structure, grain boundaries, and defects. Both contributions are, in general, influenced by the grain size (GS) . The increase in remnant polarization and coercivity for 0.50%ZB + PZT attributes to grain size effect.…”

Development and Characterization of Titanium Dioxide Ceramic Substrates with High Dielectric Permittivities

“…We observed significantly increases in dielectric permittivity with loss tangent near zero, which may lead to an expressive size reduction of electronic devices in regards to the existing commercial ones, as alumina (ε r = 9.8), gallium arsenide (ε r = 12.9), Cordelite™ (a trademark of Trans Tech Company, Chandler, AZ, USA) (ε r = 4.5) [30]. Previous studies on Ba 0.8 Sr 0.2 TiO 3 and PbTiO 3 ceramics [32,33] ascribe the changes in dielectric properties to the presence of grain boundaries and pores that constrains the electromagnetic waves.…”