Chemical synthesis and properties of ferroelectric nanostructures and nanoceramics (Comunicazione a convegno)

Type
Label
  • Chemical synthesis and properties of ferroelectric nanostructures and nanoceramics (Comunicazione a convegno) (literal)
Anno
  • 2014-01-01T00:00:00+01:00 (literal)
Alternative label
  • V. Buscaglia (2014)
    Chemical synthesis and properties of ferroelectric nanostructures and nanoceramics
    in 10th Int. Conference on Physics of Advanced Materials (ICPAM-10), Iasi, Romania, 22-28 Settembre 2014
    (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
  • V. Buscaglia (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#altreInformazioni
  • Plenary Lecture (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni
  • Institute for Energetics and Interphases, National Research Council, Genoa, Italy (literal)
Titolo
  • Chemical synthesis and properties of ferroelectric nanostructures and nanoceramics (literal)
Abstract
  • Ferroelectrics are functional materials characterized by a switchable spontaneous polarization. The most important class of ferroelectrics is represented by oxides with perovskite or perovskite-like structure with general formula ABO3. Ferroelectrics show several technologically important properties, such as piroelectricity, piezoelectricity, second harmonic generation and high dielectric constant. Therefore, compounds such as BaTiO3 and Pb(Zr,Ti)O3 have found application in transducers and actuators, biomedical imaging, diesel injection systems and multilayer ceramic capacitors. Ferroelectricity is a long-range cooperative phenomenon corresponding to the alignment of the elementary dipoles of the unit cells in domains with uniform macroscopic polarization. Consequently, the properties of ferroelectrics are significantly affected by the characteristic size of the system (thickness for thin films, diameter for wires, grain size for ceramics, etc.) when this size is reduced to the nanoscale. Surface and interface effects as well strain and depolarizing field can become very important when the system is confined in a small volume. The study of size effects in ferroelectric ceramics requires the availability of high quality, non agglomerated very fine powders (particle size of 10-20 nm) and suitable sintering methods to obtain dense nanostructured materials. High quality nanoparticles of BaTiO3, SrTiO3 and LiNbO3 can be obtained by wet chemistry methods, such as hydrothermal and solvothermal synthesis. The surface of these particles can then be modified by coating with a different compound. Densification by spark plasma sintering and related techniques results in dense nanoceramics and nanocomposites. In barium titanate nanoceramics (grain size <100 nm), a decrease of the dielectric constant, shift of the Curie temperature, suppression of polarization switching, strongly reduced tunability and thermal conductivity are commonly observed. This suggests a progressive loss of ferroelectric properties with decreasing grain size. The high density of grain boundaries typical of nanoceramics is the main responsible for these effects. (literal)
Prodotto di
Autore CNR

Incoming links:


Prodotto
Autore CNR di
data.CNR.it