Effect of niobium modifications to PZT (53/47) thin films made by a sol-gel route

• Published in: Journal of sol-gel science and technology 2003-08, Vol.28 (1), p.143-150
• Main Authors: KURCHANIA, Rajnish, MILNE, Steven J
• Format: Article
• Language: English
• Subjects: Chemistry; Coating effects; Colloidal gels. Colloidal sols; Colloidal state and disperse state; Crystallization; Dielectric properties; Exact sciences and technology; Ferroelectric materials; Ferroelectricity; General and physical chemistry; Lead zirconate titanates; Niobium; Permittivity; Perovskites; Polarization characteristics; Silicon substrates; Sol-gel processes; Spin coating; Thin films
• ISSN: 0928-0707; 1573-4846
• DOI: 10.1023/A:1025605724213

Niobium-modified lead zirconate titanate thin films (PNZT) with nominal compositions, Pb(1−0.5x) (Zr0.53 Ti0.47)1−x NbxO3:x = 0.02–0.07, have been prepared using a diol based sol-gel route. Single-layer (0.5 μm) films were fabricated on platinised silicon substrates by spin-coating. The effect of niobium additions with regard to phase development, microstructure, and ferroelectric and dielectric properties were investigated for different annealing temperatures. For comparison, unmodified PZT films were also prepared. Niobium substitution increased the crystallisation temperatures for perovskite PNZT phase formation. The values of remanent polarisation Pr and dielectric constant εr were found to decrease with the introduction of Nb. For example, in films heated at 700°C for 15 min, the Pr value of an unmodified PZT film was 31 μC cm−2, compared to 17 μC cm−2 for an x = 0.05 PNZT film, whilst respective relative permittivity values fell from 1190 to 600. The highest Nb concentration film, x = 0.07, did not display any switchable polarisation characteristics, which is consistent with high levels of intermediate pyrochlore phase.