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Memorias de investigación
Communications at congresses:
STUDY OF POLING MECHANISMS RELATED TO MICROSTRUCTURE IN Bi4Ti3O12 BASED CERAMICSave-fla
Year:2007
Research Areas
  • Ceramics,
  • Magnetic materials
Information
Abstract
Aurivillius in 1949(1), have the general formula (Bi2O2)2 (Am-1BmO3m+1)2- and are composed of pseudo-perovskite (Am-1BmO3m+1)2- blocks interleaved with bismuth oxide (Bi2O2)2+ layers along the c-axis; in this formula A represent a monovalent, divalent, or trivalent ion; B represents a tetravalent, pentavalent, or hexavalent ion, and m is the number of BO6 octahedra in the pseudo-perovskite block. The Bismuth titanate Bi4Ti3O12 (BIT) is ferroelectric, the Tc is about 675°C of pure BIT. Due to this high transition temperature, BIT ceramics are good candidates for high temperature piezoelectric applications. The principal problem is their low electrical resistivity. The electrical conductivity in BIT is highly anisotropic, with the maximum value in the same plane as the polarization. The spontaneous polarization determined in single crystals in the ab plane is ~50mC/cm2 and in the perpendicular direction is only 4 mC/cm2 (2). In this work BIT ceramics were processed by solid state synthesis from Bi2O3 and TiO2. The obtained had material different microstructure as a function of the sintering temperature due the anisotropic grain growth but their conductivy was similar became of the secondary phase Sillenite. In this work a study of the curves at hysteresis to different temperatures (RT up to 120°C) and with different mechanical stresses have been afforded. Non reported phenomenons were observed related to the temperature dependence of the ferroelectric response. An antiferroelectric type behavior was observed for grains with low plate size meanwhile a typical non symmetric ferroelectric curve ociates with microstructural defect appears for large plates with exaggerated growth. It was also found an ¿unblocking¿ field where these defects seem to be overcome and allowed to obtain ferroelectric response with Ps values of 5mC/cm2.
International
Si
Congress
EC07-ELECTROCERAMICS
960
Place
AVEIRO (PORTUGAL)
Reviewers
No
ISBN/ISSN
Start Date
24/06/2007
End Date
26/06/2007
From page
To page
Participants
  • AUTOR: M-G- NAVARRP-ROJERO (ICV-CSIC)
  • Autor: Mª Pilar Ochoa Pérez (UPM)
  • Autor: Jose de Frutos Vaquerizo (UPM)
  • Autor: Jose Francisco Fernández Lozano (UPM)
Research Group, Departaments and Institutes related
  • Creador: Grupo de Investigación: Propiedades ópticas, eléctricas y magnéticas de materiales y sus aplicaciones (POEMMA)
  • Departamento: Física Aplicada a las Tecnologías de la Información
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