Electronic, electrical and thermoelectric properties of Ba0.95Ca0.05Ti0.95Y0.05O2.975 compound: Experimental study and DFT-mBJ calculation
A. Saidi, A. Mabrouki, R. Dhahri, E. Dhahri, K. Khirouni, B. F. O. Costa
Abstract
This article explores the impact of co-doping BaTiO 3 ceramics with Ca 2+ and Y 3+ using solid-state reactions to improve its dielectric constant and decrease losses. The oxide BCTYO (Ba 0.95 Ca 0.05 Ti 0.95 Y 0.05 O 2.975 ) exhibits a tetragonal crystal structure, characterized by a space group of P 4 mm . By examining the behavior of the doped BaTiO 3 sample and performing simulations, researchers can better understand the underlying mechanisms and optimize material properties for specific applications. DFT study shows a semiconductor behavior with an indirect gap (E g = 2.5 eV). The partial DOS proves that the hybridization between the orbitals Ti 3d, Y 3d, and O 2p is responsible for the band gap and the hopping processes. The analysis of conductivity curves provides evidence for the semiconductor characteristics of the material under investigation. By determining the activation energy (E a ) through analyzing Ln(f max ) and conductivity as a function of 1000/T, the interconnection between conduction and relaxation phenomena is demonstrated. The study of the real part of the dielectric permittivity (ε′) shows a transition at T c = 380 K. The obtained results are promising and indicate that the studied material has the potential for various electronic applications (energy storage and diode fabrication …). Moreover, the thermal, electrical, and thermoelectric characteristics were examined utilizing the semi-classical Boltzmann theory. The findings revealed an intriguing result, suggesting that Ba 0.95 Ca 0.05 Ti 0.95 Y 0.05 O 2.975 holds promise as a potential candidate for application in thermoelectric devices.