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TitleComposition-dependent xBa(Zr0.2Ti0.8)O3-(1-x)(Ba0.7Ca0.3)TiO3 bulk ceramics for high energy storage applications
Author(s)Jayakrishnan, A. R.
Alex, Kevin V.
Thomas, Athul
Silva, J. P. B.
Kamakshi, K.
Dabra, Navneet
Sekhar, K. C.
Agostinho Moreira, J.
Gomes, M. J. M.
KeywordsDielectric constant
Energy storage capacitors
Lead free ceramics
Raman spectroscopy
Spontaneous polarization
Issue date2018
JournalCeramics International
CitationA.R. Jayakrishnan, Kevin V . Alex, Athul Thomas, J.P .B. Silva, K. Kamakshi, Navneet Dabra, K.C. Sekhar, J. Agostinho Moreira and M.J.M. Gomes, Composition-dependent xBa(Zr0.2Ti0.8)O3-(1-x) (Ba0.7Ca0.3)TiO3 bulk ceramics for high energy storage applications, Ceramics International,
Abstract(s)This work reports the composition dependent microstructure, dielectric, ferroelectric and energy storage properties, and the phase transitions sequence of lead free xBa(Zr0.2Ti0.8)O3-(1-x)(Ba0.7Ca0.3)TiO3 [xBZT-(1-x)BCT] ceramics, with x = 0.4, 0.5 and 0.6, prepared by solid state reaction method. The XRD and Raman scattering results confirm the coexistence of rhombohedral and tetragonal phases at room temperature (RT). The temperature dependence of Raman scattering spectra, dielectric permittivity and polarization points a first phase transition from ferroelectric rhombohedral phase to ferroelectric tetragonal phase at a temperature (TR-T) of 40 0C and a second phase transition from ferroelectric tetragonal phase - paraelectric pseudocubic phase at a temperature (TT-C) of 110 0C. The dielectric analysis suggests that the phase transition at TT-C is of diffusive type and the BZT-BCT ceramics are a relaxor type ferroelectric materials. The composition induced variation in the temperature dependence of dielectric losses was correlated with full width half maxima (FWHM) of A1, E(LO) Raman mode. The saturation polarization (Ps) ≈ 8.3 μC/cm2 and coercive fields ≈ 2.9 kV/cm were found to be optimum at composition x = 0.6 and is attributed to grain size effect. It is also shown that BZT-BCT ceramics exhibit a fatigue free response up to 105 cycles. The effect of a.c. electric field amplitude and temperature on energy storage density and storage efficiency is also discussed. The presence of high TT-C (110 0C), a high dielectric constant (εr ≈ 12285) with low dielectric loss (0.03), good polarization (Ps) ≈ 8.3 μC/cm2) and large recoverable energy density (W = 121 mJ/cm3) with an energy storage efficiency (η) of 70 % at an electric field of 25 kV/cm in 0.6BZT 0.4BCT ceramics make them suitable candidates for energy storage capacitor applications.
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Appears in Collections:CDF - FMNC - Artigos/Papers (with refereeing)

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