Journal of the European Ceramic Society 25 (2005) 2453–2456 Texture development and dielectric properties of SrBi 2 Ta 2 O 9 ceramics processed by templated grain growth H. Amor´ ın ∗ , A.L. Kholkin, M.E.V. Costa Department of Ceramics and Glass Engineering, CICECO, University of Aveiro, Aveiro 3810-193, Portugal Available online 12 April 2005 Abstract SrBi 2 Ta 2 O 9 (SBT) textured ceramics were produced by templated grain growth (TGG) using anisometric templates grown by self-flux solution method. SBT templates (5 wt.%) with the dimensions ∼40 m × 40 m × 8 m were embedded in a fine-grained matrix of SBT powder containing a 3 wt.% of Bi 2 O 3 excess and partially aligned by conventional uniaxial pressing. Textured SBT ceramics characterized by a Lotgering factor f ≈ 0.4 could then be obtained after sintering at 1250 ◦ C for 2 h. The influence of the pressing and sintering conditions on texture development was evaluated using scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD). Significant improvement of the dielectric and ferroelectric properties was observed when measurements are performed perpendicularly to the pressing direction. This improvement was attested to the apparent alignment of the templates, dielectric anisotropy of SBT and texturing effect due to TGG. © 2005 Elsevier Ltd. All rights reserved. Keywords: Bi-layered ferroelectrics; Ferroelectric properties 1. Introduction Following a general trend of developing lead-free piezo- electric components, bismuth layer structure ferroelectrics (BLSF), in particular SrBi 2 Ta 2 O 9 (SBT), are recently emerged as promising candidates for high-temperature piezo- electric applications. 1 However, it is difficult to achieve high piezoelectric response in randomly oriented BLSF polycrys- talline materials because of the two-dimensional character of ferroelectric switching. 2,3 Thus, the study of textured BLSF ceramics is of fundamental importance for tailoring their piezoelectric and dielectric properties and improving sens- ing and actuating capabilities of various devices. One of the promising routes for the controlled texture de- velopment is a templated grain growth (TGG). 4–8 This pro- cess consists of the ceramics sintering mediated by a small amount of well-oriented anisometric template particles dis- tributed in a fine-grained matrix. The template particles grow at the expense of the fine randomly oriented powder ensuring the large fraction of highly oriented grains. 9 Being based on ∗ Corresponding author. Fax: +351 234 425300. E-mail address: hamorin@cv.ua.pt (H. Amor´ ın). a standard powder processing and sintering, TGG achieves texture at significantly lower cost as compared to other tech- niques including hot forging or hot pressing. TGG has been reported for a variety of materials, 4–8 in- cluding some BLSFs. 4–6 However, because of the complexity of SBT single crystal synthesis, to the best of our knowledge, this technique has not been used for SBT so far. In this work, textured SBT ceramics were produced by TGG using aniso- metric SBT platelets and the anisotropy of the dielectric and ferroelectric properties was studied. 2. Experimental procedure Plate-like SBT crystals were grown by a high-temperature self-flux solution method described elsewhere. 10 SBT crys- tals of rectangular shape with the [0 0 1] direction (c-axis) perpendicular to the major face were milled and sieved to obtain anisometric templates with an average size of ∼40 m × 40 m × 8 m. Polycrystalline SBT powder was synthesized via solid-state reaction. Subsequently, a 3 wt.% of Bi 2 O 3 excess for promoting liquid phase during TGG was added to the SBT powder together with the 5 wt.% of 0955-2219/$ – see front matter © 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.jeurceramsoc.2005.03.081