Effect of different templates on reactive templated grain growth of BiFeO3-PbTiO3

The rhombohedral perovskite BiFeO₃, which displays both antiferromagnetic and ferroelectric properties at room temperature, has a ferroelectric Curie point of 836 °C. The solid solution between bismuth ferrite and lead titanate, which is perovskite with either tetragonally or rhombohedrally distorted lattice and a ferroelectric Curie point around 490°C, (xBiFeO₃-(1-x)PbTiO₃ or BFPT) possesses a morphotropic phase boundary (MPB) between the rhombohedral and tetragonal forms at x=0.7, with a spontaneous strain of 18% on the tetragonal side of the boundary. Coupling between the ferroelectric and magnetic orders near the MPB would be facilitated by the availability of crystallographically textured ceramics. The approach taken here is to investigate templated grain growth (TGG) as a route to produce oriented BFPT. TGG utilizes an oriented template as a seed to regulate preferred directional growth within a polycrystalline matrix. In this example we have employed different types of templates such as Bi₄Ti₃O₁₂, BaTiO₃ and SrTiO₃. X-ray diffraction and scanning electron microscopy have been used to examine the influence of the different templates. We have shown that by using Bi₄Ti₃O₁₂ the texture in BFPT ceramic has been improved.