Study of electrical properties with temperature variation by complex impedance spectroscopy (CIS) and effects on the Ba2TiSi2O8–TiO2 matrix

• Published in: Applied physics. A, Materials science & processing Vol. 130; no. 2
• Main Authors: Abreu, R. F., Saturno, S. O., Nobrega, F. A. C., da M. Colares, D., do Nascimento, J. P. C., Vasconcelos, S. J. T., Nogueira, F. E. A., de Freitas, D. B., do Carmo, F. F., Ghosh, A., Abreu, T. O., Silva, M. A. S., Silva, R. S., Trukhanov, S. V., Zhou, Di, Singh, C., Sombra, A. S. B.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-02-2024; Springer Nature B.V
• Subjects: Characterization and Evaluation of Materials; Composite materials; Condensed Matter Physics; Dielectric properties; Electrical properties; Equivalent circuits; Grain boundaries; Impedance spectroscopy; Machines; Manufacturing; Nanotechnology; Nyquist plots; Optical and Electronic Materials; Permittivity; Physics; Physics and Astronomy; Processes; Radio frequency; Spectrum analysis; Storage systems; Surfaces and Interfaces; Thin Films; Titanium dioxide; composites; Colossal permittivity; TiO; TiSi; Ba; O; Impedance spectroscopy (IS)
• ISSN: 0947-8396; 1432-0630
• DOI: 10.1007/s00339-024-07295-z

The present work shows the dielectric properties of (100-X)Ba
2
TiSi
2
O
8
–(X)TiO
2
composites (X in wt%) at radio frequency (RF) region (< 300 MHz). X-ray diffraction and Rietveld’s refinement showed the presence of Ba
2
(Ti
7/9
Si
2/9
)
9
O
20
(BTSO) phase in the studied composites. To analyze the relationship between the electrical properties and the microstructure of the matrix and composites, Impedance spectroscopy (IS) was used. The applied model that best describes the behavior found in the samples is the Havriliak–Negami model. From the IS it was observed that the dielectric relative permittivity presented high values in BTS10 (
X
 = 10%) and BTS20 (
X
 = 20%) which allows classifying them as Colossal permittivity materials. This is an important result due to the potential for applications in new storage systems, capacitive devices and microelectronics. Nyquist diagrams were employed to evaluate the contribution of the grain and grain boundary in the electrical response of the samples and fitted employing an equivalent circuit with two associations of R-CPE (constant phase element). Temperature coefficient of capacitance (TCC) was also obtained and it was possible to observe that there was an increase in the TCC value for the compounds in all frequencies. In addition, IS demonstrated that the activation energy decreasing with TiO
2
addition indicating a decrease in the resistive character of the materials.