Ferroelectric and piezoelectric properties of lead-free BaTiO3 doped Bi0.5Na0.5TiO3 thin films from metal-organic solution deposition

• Published in: Journal of alloys and compounds 2012-11, Vol.540, p.204-209
• Main Authors: Acharya, Susant Kumar, Lee, Sang-Kwon, Hyung, Jung-Hwan, Yang, Yun-Ho, Kim, Bok-Hee, Ahn, Byung-Guk
• Format: Article
• Language: English
• Subjects: Coercive force; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Density; Deposition; Dielectric response; Dielectric thin films; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Domain structure; hysteresis; Electric fields; Exact sciences and technology; Ferroelectric materials; Ferroelectricity; Ferroelectricity and antiferroelectricity; Ferroelectrics; Physics; Piezoelectricity; Piezoelectricity and electromechanical effects; Thin films
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2012.06.071

► Lead-free BNT–BT thin films from an optimized metal-organic solution deposition. ► Phase and microstructure evolution with annealing temperature. ► A relatively low leakage current density. ► Good dielectric constant of 613 at a frequency of 1kHz. ► High remanent polarization and piezoelectric constant comparable to PZT thin films. Lead-free 0.94Bi0.5Na0.5TiO3–0.06BaTiO3 (BNT–BT) piezoelectric thin films were prepared by metal-organic solution deposition onto a Pt/Ti/SiO2/Si substrate. A dense and well crystallized thin film with a perovskite phase was obtained by annealing these films at 700°C. Atomic force microscopy showed that these films were smooth and crack-free with an average grain size on the order of 200nm. Thin films of 356nm thickness exhibited a small signal dielectric constant and a loss tangent at 1kHz of 613 and 0.044, respectively. Ferroelectric hysteresis measurements indicated a remanent polarization value of 21.5μC/cm2 with a coercive field of 164.5kV/cm. The leakage current density of the thin film was 4.08×10−4A/cm2 at an applied electric field of 200kV/cm. A typical butterfly-shaped piezoresponse loop was observed and the effective piezoelectric coefficient (d33) of the BNT–BT thin film was approximately 51.6pm/V.