Publicação
Dielectric and impedance spectroscopic studies of lead-free barium-calcium-zirconium-titanium oxide ceramics
| Resumo: | Dielectric properties of perovskite structured (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3; [BCZT],ferroelectric ceramics prepared by the conventional solid state reaction method were investigated by AC impedance spectroscopy. To obtain high density samples, the pressed pellets were sintered at 1450ºC and 1500 ºC for 4h. Polarization Electric field (P E) measurements of the ceramic samples sintered at 1500 ºC showed higher remnant polarization (Pr 12.20 mC/cm2) andcoercive field (Ec 4.50 kV/cm) values when compared to Pr 8.02 mC/cm2 and Ec 3.80 kV/cm respectively for the samples sintered at 1450 ºC. In addition, BCZT sintered at 1500 ºC showed higher dielectric constant as compared to the one sintered at 1450 ºC. However,the dielectric constant measured as a function of frequency for both the sintered samples showed single maximum value at 105 ºC, which is attributed to the structural phase transition (Curie temperature, TC) from ferroelectric, tetragonal phase to paraelectric, cubic phase.AC impedance analysis over the frequency range of 100Hz to 1MHz for the ceramic sintered at 1500 ºC, showed mainly bulk contribution up to 250 ºC while bulk and grain boundary contributions were present above 250 ºC. Activation energies for conductivity were found to be strongly frequency dependent. The activation energy values are attributed to the conduction of oxygen vacancies via hopping mechanism. |
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| Autores principais: | Rafiq, Muhammad Asif |
| Outros Autores: | Rafiq, Muhammad Nadeem; Saravanan, K Venkata |
| Assunto: | C. Dielectricproperties C.Impedance D.Perovskite Grainboundary Activationenergy Hoppingmechanism |
| Ano: | 2015 |
| País: | Portugal |
| Tipo de documento: | artigo |
| Tipo de acesso: | acesso restrito |
| Instituição associada: | Universidade de Aveiro |
| Idioma: | inglês |
| Origem: | RIA - Repositório Institucional da Universidade de Aveiro |
| Resumo: | Dielectric properties of perovskite structured (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3; [BCZT],ferroelectric ceramics prepared by the conventional solid state reaction method were investigated by AC impedance spectroscopy. To obtain high density samples, the pressed pellets were sintered at 1450ºC and 1500 ºC for 4h. Polarization Electric field (P E) measurements of the ceramic samples sintered at 1500 ºC showed higher remnant polarization (Pr 12.20 mC/cm2) andcoercive field (Ec 4.50 kV/cm) values when compared to Pr 8.02 mC/cm2 and Ec 3.80 kV/cm respectively for the samples sintered at 1450 ºC. In addition, BCZT sintered at 1500 ºC showed higher dielectric constant as compared to the one sintered at 1450 ºC. However,the dielectric constant measured as a function of frequency for both the sintered samples showed single maximum value at 105 ºC, which is attributed to the structural phase transition (Curie temperature, TC) from ferroelectric, tetragonal phase to paraelectric, cubic phase.AC impedance analysis over the frequency range of 100Hz to 1MHz for the ceramic sintered at 1500 ºC, showed mainly bulk contribution up to 250 ºC while bulk and grain boundary contributions were present above 250 ºC. Activation energies for conductivity were found to be strongly frequency dependent. The activation energy values are attributed to the conduction of oxygen vacancies via hopping mechanism. |
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