Substrate-induced dielectric polarization in thin films of lead-free (Sr0.5Bi0.5)(2)Mn2-xTixO6-delta perovskites grown by pulsed laser deposition

作者：Alvarez Serrano I; Ruiz de Larramendi I; Lopez M L; Veiga M L

来源：Applied Surface Science, 2017, 399: 387-395.

DOI：10.1016/j.apsusc.2016.12.052

• Pulsed laser deposition
• Lead-free perovskite
• Dielectric polarization
• Relaxor

Thin films of SrBiMn(2-x)Ti(x)O(6- delta)have been fabricated by Pulsed Laser Deposition on SrTiO3 [100] and [111] substrates. Their texture, width, homogeneity and morphology are evaluated by means of XRD, SEM, XPS, whereas complex impedance spectroscopy is employed to analyze their electrical response. The thickness values range between 80 and 900 nm depending on the experimental conditions. The epitaxial growing could be interpreted in terms of two contributions of microstructural origin: a matrix part and some polycrystalline surface formations (hemi-spheres). Texture studies suggest a fiber-type orientated morphology coherently with the Scanning Electron Microscopy images. XPS analyses indicate a segregation regarding A-sublattice cations, which features depend on the substrate orientation. This segregation could be connected to the development of nanopolar regions. Impedance data show the electrical polarization in the samples to be enhanced compared to bulk response of corresponding powdered samples. A relaxor behavior which fits a Vogel-Fulcher law is obtained for x = 0.50 whereas an almost frequency-independent relaxor ferroelectric behavior is registered for the thinnest film of x = 0.25 composition grown on SrTiO3 [111] substrate. The influence of compositional and structural aspects in the obtained dielectric response is analyzed.

• 出版日期2017-3-31