Effect of B-site isovalent doping on electrical and ferroelectric properties of lead free bismuth titanate ceramics

• Structural, electrical and ferroelectric properties of Zr4+ modified Bi4Ti3O12 are explored.
• Orthorhombic distortion is introduced in BIT lattice due to Zr4+ addition.
• Chemically stable Zr4+ reduces the conductivity thus enhancing its εr and Pr.
• Ez due to relaxation is greater than that due to conduction-conduction is not due to relaxation of dipoles.

In the present work, zirconium modified bismuth titanate ceramics have been studied as potential lead-free ferroelectric materials over a broad temperature range (RT – 800 °C). Polycrystalline samples of Bi4Ti3−xZrxO12 (x=0.2, 0.4, 0.6) (BZrT) with high electrical resistivity were prepared using the solution combustion technique. The effect of Zr doping on the crystalline structure, ferroelectric properties and electrical conduction characteristics of BZrT ceramics were explored. Addition of zirconium to bismuth titanate enhances its dielectric constant and reduces the loss factor as it introduces orthorhombic distortion in bismuth titanate lattice which is exhibited by the growth along (0010) lattice plane. Activation energy due to relaxation is found to be greater than that due to conduction thus confirming that electrical conduction in these ceramics is not due to relaxation of dipoles. Remanent polarization of the doped samples increases as the Zirconium content increases.

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