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Studies of the temperature coefficient of capacitance (TCC) of a new electroceramic composite: Pb(Fe0.5Nb0.5)O3 (PFN)–Cr0.75Fe1.25O3(CRFO)

  • F. N. A. Freire
  • M. R. P. Santos
  • F. M. M. Pereira
  • R. S. T. M. Sohn
  • J. S. Almeida
  • A. M. L. Medeiros
  • E. O. Sancho
  • M. M. Costa
  • A. S. B. Sombra
Article

Abstract

In this paper we did a study of the dielectric properties: capacitance (C), dielectric permittivity(ε), electric modulus(M) and dielectric loss(tangα)) in the radio-frequency(RF) and microwave (MW) frequency range as a function of temperature and the temperature coefficient of capacitance (TCC) of the composites [Pb(Fe1/2Nb1/2)O3(PFN)]Z–[CrYFe2−YO3(CRFO)]100−Z where Z = 0, 10, 50, 90 and 100%. The compounds were prepared by the powder-sintering and the X-ray diffraction (XRD) was used in this study using the Rietveld procedure. The X-ray analysis shows that PFN phase is tetragonal where the CRFO phase belongs to a trigonal structure. The capacitance, dielectric permittivity, electric modulus and loss were studied in the frequency range of 100 Hz to 1GHz and temperature range of 25–100 °C. The values of TCC for all the samples are presenting positive values. The study of the electric modulus (M) as a function of frequency and temperature lead to the measurement of the activation energy (Eac), which is directed linked to the relaxation process associated to the interfacial polarization effect in the samples. The study of the electrical properties in the RF and MW range of frequencies is important in view of possible applications of these composites as future components in RF and MW circuits.

Keywords

Dielectric Property Dielectric Permittivity Measured Capacitance Chromium Oxide Relaxation Peak 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Notes

Acknowledgements

This work partly sponsored by CAPES, FUNCAP and CNPq (Brazilian agencies) and the U.S. Air Force Office of Scientific Research (AFOSR) (FA9550-06-1-0543).

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Copyright information

© Springer Science+Business Media, LLC 2008

Authors and Affiliations

  • F. N. A. Freire
    • 1
    • 2
    • 3
  • M. R. P. Santos
    • 2
  • F. M. M. Pereira
    • 1
    • 2
  • R. S. T. M. Sohn
    • 2
  • J. S. Almeida
    • 2
  • A. M. L. Medeiros
    • 2
    • 4
  • E. O. Sancho
    • 2
  • M. M. Costa
    • 5
  • A. S. B. Sombra
    • 2
  1. 1.Departamento de Química Orgânica e InorgânicaUniversidade Federal do CearáFortalezaBrasil
  2. 2.Laboratório de Telecomunicações e Ciência e Engenharia dos Materiais (LOCEM), Departamento de FísicaUniversidade Federal do CearáFortalezaBrasil
  3. 3.Faculdade de Educação, Ciências e Letras do Sertão Central – Curso de QuímicaUniversidade Estadual do CearáQuixadaBrasil
  4. 4.Departamento de Engenharia de TeleinformáticaUniversidade Federal do CearáFortalezaBrasil
  5. 5.Departamento de FísicaUniversidade Federal de MatogrossoCuiabáBrasil

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