Effect of biphase on dielectric properties of Bi-doped lead strontium titanate thin films

• Published in: Journal of solid state chemistry Vol. 183; no. 11; pp. 2598 - 2601
• Main Authors: Li, X.T., Du, P.Y., Zhao, Y.L., Tu, Y., Dai, J.L., Weng, W.J., Han, G.R., Song, C.L.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.11.2010; Elsevier
• Subjects: ALKALINE EARTH METAL COMPOUNDS; Biphase; BISMUTH; COHERENT SCATTERING; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Dielectric constant; DIELECTRIC MATERIALS; DIELECTRIC PROPERTIES; Dielectric thin films; Dielectrics, piezoelectrics, and ferroelectrics and their properties; DIFFRACTION; DOPED MATERIALS; ELECTRICAL PROPERTIES; ELECTRON MICROSCOPY; ELEMENTS; Exact sciences and technology; IMPEDANCE; LEAD COMPOUNDS; MATERIALS; MATERIALS SCIENCE; METALS; MICROSCOPY; MINERALS; MORPHOLOGY; OXIDE MINERALS; OXYGEN COMPOUNDS; PERMITTIVITY; PEROVSKITE; PEROVSKITES; PHYSICAL PROPERTIES; Physics; PST; PYROCHLORE; Pyrochlores; SCANNING ELECTRON MICROSCOPY; SCATTERING; SOL-GEL PROCESS; Sol–gel processes; STRONTIUM COMPOUNDS; STRONTIUM TITANATES; THIN FILMS; TITANATES; TITANIUM COMPOUNDS; TRANSITION ELEMENT COMPOUNDS; X-RAY DIFFRACTION; X-rays; Thin films; PST; Sol–gel processes; Dielectric properties; Biphase; Pyrochlore; Scanning electron microscopy; Surface morphology; Doping; Twinning; Perovskites; XRD; Bismuth Titanates; Bismuth additions; Dielectric losses; Dielectric thin films; Surface properties; Sol-gel processes; Lead Strontium Titanates Mixed; Permittivity; Sol-gel process; Figure of merit
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/j.jssc.2010.09.007

Pb 0.4Sr 0.6TiO 3 (PST) thin films doped with various concentration of Bi were prepared by a sol–gel method. The phase status, surface morphology and dielectric properties of these thin films were measured by X-ray diffraction (XRD), scanning electron microscopy (SEM) and impedance analyzer, respectively. Results showed that the thin films with the maximum dielectric constant and minimum dielectric loss were obtained for x=0.15. For x<0.15, only pure PST perovskite phase were in the thin films. For 0.2< x<0.4, the PST/Bi 2Ti 2O 7 biphase were obtained. The thin films with pure Bi 2Ti 2O 7 pyrochlore phase were obtained for x=0.67. The biphase thin films had high tunability and high figure of merit (FOM). The FOM of PST/Bi 2Ti 2O 7 biphase thin film was about 6 times higher than that thin films formed with pure perovskite phase or pure pyrochlore phase. The Bi-doped Pb 0.4Sr 0.6TiO 3 (PST) thin films prepared by the sol–gel method showed a PST/Bi 2Ti 2O 7 biphase structure for 0.2< x<0.4, and had the low dielectric capacitance and dielectric loss. [Display omitted]