Characterization of Niobium-Doped Lead Titanate Thin Films

Abstract

Lead titanate ( PbTiO3) thin films were deposited on silicon substrates covered with platinum by reactive sputtering using a single multicomponent-type target at high temperatures (around 500° C). Small chips of metallic niobium were incorporated into the target for doping purposes. Samples analyzed in this study were fabricated in such a way that the molar concentration of niobium was kept at 0, 1, 2, 3, or 4%. X-ray diffraction (XRD) patterns showed that samples doped with niobium tended to exhibit epitaxial growth on top of a (111)-oriented platinum electrode. At 2 mol% niobium doping, the tetragonality ratio (c/a) exhibited a maximum value and the dielectric permittivity showed a local minimum. The dielectric loss and leakage current characteristics of Nb-doped films were considerably improved. Electric displacement-electric field (D-E) hysteresis loops were observed at all doping concentrations. Some promising acoustic surface wave characteristics were also observed. Samples with 1 or 2 mol%Nb seem to be very promising candidates for integrated devices.

Fifteen years of the first Brazilian Centrifugal Ventricular Assist Device for long term Mechanically Assisted Circulatory Support

“…But the fact is that several parallel projects, within the IDPC, USP, and even in the Instituto Federal de São Paulo (IFSP) were born from that interaction, such as the electromagnetic suspension for a fourth generation of CFVADs (38)(39)(40)(41)(42)(43)(44)(45)(46)(47)(48)(49)(50)(51).…”

Main characteristics of Pb0.85Sm0.1TiO3 ferroelectric thin films with Bi2Ti2O7 buffer layer

“…Imitating PLT or PCLT [2,3], we chose samarium as dopant, and successfully prepared Sm-doped PbTiO 3 (PST) thin film on p-type Si(1 1 1) substrate [4]. Because Pb is highly reactive with Si and easily diffuses into Si substrate [5], we want to suppress the diffusion at the interface between PbTiO 3 and Si substrate by using a buffer layer, such as SrTiO 3 [6] and CeO 2 [7] or Pt [8], which plays an important role in the growth of high quality ferroelectric thin film. Bi 2 Ti 2 O 7 exhibits no ferroelectricity or piezoelectricity.…”

(Pb, Sm)TiO3 THIN FILMS PREPARED BY CHEMICAL SOLUTION DEPOSITION USING A Bi2Ti2O7 BUFFER LAYER

“…4 Thus, various buffer layers have been proposed for obtaining a good ferroelectric-Si interface, such as SrTiO 3 , CeO 2 , Pt and SiO 2 . [5][6][7][8] Bi 2 Ti 2 O 7 exhibits no ferroelectricity or piezoelectricity. But it has a relatively high dielectric constant and good insulation.…”