Ferroelectric (Na1/2_{1/2}Bi1/2_{1/2})TiO3_{3}-BaTiO3_{3} thin films obtained by pulsed laser deposition

The solid solution of the ferroelectric relaxor (Na$_{1/2}$Bi$_{1/2})$TiO$_{3}$ with BaTiO$_{3}$, (1-x) NBT-x BT (NBT-BT) shows a morphotropic phase boundary with enhanced properties at x = 0.06-0.07. We have prepared targets of (1-x) NBT-x BT with x = 0.06 by solid state reaction and sintering at 1200 $^{\circ}$C, up to a final relative density of 97.8%. Films from these targets have been deposited on MgO substrates by pulsed laser deposition, in different substrate temperature and heating rate conditions. First results obtained from structural, AFM and electrical characterization are reported. The obtained films are polycrystalline perovskite with a slight (100) orientation. High relative dielectric constant, of about 1300, have been obtained

Properties of zirconium silicate thin films prepared by lase ablation

Thin films of zirconium silicate were obtained by alternative ablation of Zr and Si targets in oxygen reactive atmosphere; in a set of experiments a radiofrequency (RF) discharge beam was added to the pulsed laser deposition (PLD) system. Pt-coated silicon, Sapphire and glass were used as collectors. The third harmonics of the Nd:YAG laser (λ = 355 nm) working at 10 Hz and at a laser fluence varying in the range of (4-6 J/cm 2) was used. The oxygen pressure varied between 1 and 10 Pa and the substrate holder was kept at room temperature. The RF beam addition influence on the electrical, optical and morphological proprieties of zirconium silicate films was particularly investigated. The obtained films, with thicknesses in the range of 15-60nm, have been characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD) and electrical measurements. Dielectric permittivity values (real part) in the range of 7-13 and low losses (0.008-0.015) were measured for samples prepared with the RF oxygen beam addition

Lead-Free Piezoelectric (Ba,Ca)(Zr,Ti)O₃ Thin Films for Biocompatible and Flexible Devices

In this work, we report the synthesis of functional biocompatible piezoelectric (1 – <i>x</i>)­Ba­(Ti_0.8Zr_0.2)­TiO₃–<i>x</i>(Ba_0.7Ca_0.3)­TiO₃, <i>x</i> = 0.45 (BCZT45), thin films with high piezoelectric properties. Pulsed-laser-based techniques, classical pulsed-laser deposition and matrix-assisted pulsed-laser evaporation, were used to synthesize the BCZT45 thin films. The second technique was employed in order to ensure growth on polymer flexible Kapton substrates. The BCZT45 thin films grown by both techniques show similar structural properties and high piezoelectric coefficient coupling between the mechanical loading and electrical potential. While it has long been shown that the electrical potential favors biological processes like osteogenesis, the assessment of cell adhesion and osteogenic differentiation onto BCZT materials has not yet been demonstrated. We prove here for the first time that BCZT 45 coatings on Kapton polymer substrates provide optimal support for osteogenic differentiation of mesenchymal stem cells in the bone marrow