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  1. No Access

    Article

    Structural, electrical, and impedance properties of Co and Sn doped Ba0.5Sr0.5Fe12-2xO19 hexaferrite ceramics (0 ≤ x ≤ 1) and their evaluation for antenna application

    The effect of do** of Co2+ and Sn4+ in Ba0.5Sr0.5Fe12-2xO19 hexaferrite with different concentrations (x = 0.2, 0.4, 0.6, 0.8, and 1.0) was studied by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM)...

    Charanjeet Singh, Jasbir Singh, J. E. V. de Morais, R. G. M. Oliveira… in Applied Physics A (2023)

  2. No Access

    Article

    Impedance and Mössbauer spectroscopy study of BiCu3Ti3FeO12 dielectric matrix

    In the present work, an electroceramic of the perovskite family, BiCu3Ti3FeO12 (BCTFO), was synthesized by the solid-state reaction method. The structural study was performed by X-ray diffraction and Mössbauer an...

    D. B. Freitas, M. H. Bezerra Júnior… in Journal of Materials Science: Materials in… (2021)

  3. No Access

    Article

    High-bandwidth microwave dielectric resonator antennas from BiVO4/ZnO composites

    This study reports the dielectric and structural characterisation of composites formed by the mixture of a BiVO4 ceramic matrix with ZnO (25, 50, and 75 wt.%) obtained through a solid-state method procedure for a...

    R. G. M. Oliveira, J. E. V. de Morais… in Journal of the Australian Ceramic Society (2021)

  4. No Access

    Article

    Impedance spectroscopy analysis of an FeNbO4 matrix with different additions of TiO2 and the effects of temperature variation

    In this work, investigations of the FeNbO4 ceramic matrix (FNO) and TiO2 additions were carried out in 0, 20, 40, 60, and 80% wt. proportions. The material was synthesized using the solid-state reaction method in...

    M. H. Bezerra Junior, T. O. Abreu… in Journal of Materials Science: Materials in… (2021)

  5. No Access

    Article

    Enhancing the electrical properties of Bi4Ti3O12 (BiT) matrix by special alloying and sintering

    In this work, the electrical properties of Bi4Ti3O12 (BiT) were investigated; those presenting interesting electrical and dielectric properties in the radiofrequency (RF) and microwave (MW) range were analysed. B...

    V. L. Bessa, J. E. V. De Morais… in Journal of Materials Science: Materials in… (2020)

  6. No Access

    Article

    Effect of (Pr-Yb) Co-do** on the Luminescence and Dielectric Behaviour of LaNbO4 Ceramic

    This paper analysed the effects of do** with Pr and Yb on the dielectric and down-conversion luminescence properties in the ceramic matrix LaNbO4. X-ray diffraction analysis showed that no additional phases wer...

    J. P. C. do Nascimento, R. G. M. Oliveira… in Journal of Electronic Materials (2020)

  7. No Access

    Article

    High thermal stability of RF dielectric properties of BiVO4 matrix with added ZnO

    In this work, a complex impedance spectroscopy study of bismuth vanadate (BiVO4) ceramics with different additions of ZnO (25, 50, and 75 wt %) was performed. BiVO4 (BVO) was synthesized by the reaction method in...

    R. G. M. Oliveira, D. C. Souza… in Journal of Materials Science: Materials in… (2020)

  8. No Access

    Article

    Effects of TiO2 Addition on the Radio-Frequency Properties of the Sr2CoNbO6 Matrix

    In this work, the investigation of Sr2CoNbO6–TiO2 composite, which shows interesting dielectric characteristics (low loss and high dielectric permittivity), was carried out. The Sr2CoNbO6(SCNO) system is widely a...

    J. E. V. de Morais, R. G. M. Oliveira, V. L. Bessa… in Journal of Electronic Materials (2020)

  9. No Access

    Article

    Dielectric Resonator Antennas with Frequency Stability Under Severe Temperature Variations Based on Li2MgTi3O8 Ceramic Matrix Added with Bi2O3

    This paper presents the application of the Li2MgTi3O8 (LMT) ceramic matrix added with small quantities (0 wt.%, 1 wt.%, 3 wt.%, and 5 wt.%) of Bi2O3 for building and studying dielectric resonator antennas (DRA) t...

    J. W. O. Bezerra, R. G. M. Oliveira, M. A. S. Silva… in Journal of Electronic Materials (2018)

  10. No Access

    Article

    RF and Microwave Electrical Properties Study of the Magneto-Dielectric Resonator Antenna of the Matrix Composite [SrFe12O19 (SFO)1−x-BiFeO3(BFO)x]

    In this work, we prepared ceramic composites based on SrFe12O19 (SFO)-BiFeO3 (BFO) strontium hexaferrite. The SFO and BFO were synthesized by the solid-state reaction method, and we used both x-ray diffraction an...

    J. E. V. de Morais, R. G. M. Oliveira, V. L. Bessa… in Journal of Electronic Materials (2018)

  11. No Access

    Article

    Dielectrical and structural studies of composite matrix BiVO4–CaTiO3 and temperature effects by impedance spectroscopy

    In this work, we have analysed the effects of adding CaTiO3 (CTO) and changing the temperature on the dielectric and electric properties of ceramic matrix BiVO4 (BVO) in the radiofrequency range. BVO was synthesi...

    R. G. M. Oliveira, D. B. Freitas… in Journal of Materials Science: Materials in… (2018)

  12. No Access

    Article

    Structural and dielectric behaviour analysis of TiO2 addition on the ceramic matrix BiVO4

    In this work, the dielectric and electric properties of the ceramic matrix BiVO4 (BVO) and the effects of the addition of TiO2 were analysed by impedance spectroscopy (IS). The BVO phase was calcined at 773 K and...

    R. G. M. Oliveira, G. S. Batista… in Journal of Materials Science: Materials in… (2018)

  13. No Access

    Article

    Magneto Tuning of a Ferrite Dielectric Resonator Antenna Based on LiFe5O8 Matrix

    LiFe5O8 (LFO) spinel-like material has been studied for use in ferrite resonator antennas (FRAs). Antenna parameters such as gain and return loss were greatly affected when an external magnetic field was applied ...

    J. E. V. de Morais, A. J. N. de Castro… in Journal of Electronic Materials (2018)

  14. No Access

    Article

    Impedance Spectroscopy Analysis of Mg4Nb2O9 Ceramics with Different Additions of V2O5 for Microwave and Radio Frequency Applications

    The complex impedance spectroscopy study of magnesium niobate Mg4Nb2O9 (MN) ceramics with different additions of V2O5 (0%, 2%, 5%) was performed in this present paper. The preparation of MN samples were carried o...

    J. M. S. Filho, C. A. Rodrigues Junior, D. G. Sousa… in Journal of Electronic Materials (2017)

  15. No Access

    Chapter and Conference Paper

    Teaching Modern Physics for Future Physics Teachers

    In this work we present a new way for teaching Modern Physics to students of course for teachers formation. One of the great difficulties faced by the teachers of the secondary schools of the State of Ceará, i...

    E. F. Nobre, A. O. Feitosa, M. V. P. Lopes… in Frontiers of Fundamental Physics and Physi… (2014)

  16. No Access

    Article

    Impedance spectroscopy study of TiO2 addition on the ceramic matrix Na2Nb4O11

    In this paper a study of TiO2 addition (0, 2, 5 and 10 wt%) and its effects in the impedance spectra of Na2Nb4O11 ceramic matrix was carried out. The structural, dielectric properties of the addition in the Na2N...

    M. C. Romeu, R. G. M. Oliveira… in Journal of Materials Science: Materials in… (2013)