Enhanced dielectric and ferroelectric properties of lead-free Ba(Zr0.15Ti0.85)O3 ceramics compacted by cold isostatic pressing

• Synthesised nano-crystalline Ba(Zr0.15Ti0.85)O3 powders using high energy milling.
• High density (>98%) BZT ceramics were obtained by using cold isostatic pressing.
• Remanent polarization of ∼10 μC/cm2 and strain of 0.1% at 40 kV/cm were obtained.
• Measured piezoelectric strain coefficient d33∗ was 185 pC/N, twice the reported value.
• Observed properties are comparable to single crystals of the same composition.

Nano-sized zirconium substituted barium titanate, Ba(Zr0.15Ti0.85)O3, hereinafter referred to as BZT was synthesised using high energy ball milling. Calcined powders were compacted using cold-isostatic pressing. Phase pure perovskite BZT, free from any secondary peaks was observed for sintered samples with a relative density ∼98%. High permittivity of ∼14,000 coupled with a dielectric loss of <2% were measured on these samples. A high remanent polarization of ∼10 μC/cm2 and an electric field induced unipolar strain of 0.1% at relatively low fields (∼40 kV/cm) at room temperature are other characteristic highlights of these ceramics. The effect of hysteresis parameters such as voltage, frequency and temperature on the polarization and electric field induced strain are also reported in this paper. The observed enhanced dielectric, ferroelectric and piezoelectric properties can be a result of the contribution of all polar vectors of various coexisting phases at the composition studied and are comparable to single crystals of the same composition.