Effect of Sr-substitution on structure, dielectric relaxation and conduction phenomenon of BaTiO3 perovskite material

• Published in: Journal of materials science. Materials in electronics Vol. 32; no. 9; pp. 11453 - 11466
• Main Authors: Moussi, Rafik, Bougoffa, Amira, Trabelsi, Abdessalem, Dhahri, Essebti, M.P.F.Graça, Valente, M. A., Barille, R.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-05-2021; Springer Nature B.V
• Subjects: Barium titanates; Characterization and Evaluation of Materials; Chemistry and Materials Science; Crystal structure; Crystallography; Dielectric properties; Dielectric relaxation; Fourier transforms; Frequency ranges; Hopping conduction; Infrared spectroscopy; Materials Science; Morphology; Nanoparticles; Optical and Electronic Materials; Optical properties; Perovskites; Physical properties; Room temperature; Spectrum analysis; Strontium; Substitutes; Temperature; X ray powder diffraction
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-021-05604-3

In this paper, we investigated the impact of the substitution of barium (Ba) by strontium (Sr) in site A of the BaTiO
3
perovskite lattice on physical properties. The studied materials were synthesized via the conventional solid-state method. Then, the purity and the crystallographic structure of the prepared materials were carried out at room temperature by X-ray powder diffraction (XRD) proving an orthorhombic system with a P4mm space group. Their morphology and the particle size were evaluated by scanning electron microscope (SEM) which shows a nanoparticle agglomeration of about 2.4 µm and 2.7 µm respectively for BT and BST samples. The investigation of the optical properties by Fourier transform infrared spectroscopy confirms the successful preparation of the perovskite materials. The study of the dielectric properties of ceramic materials performed by impedance spectroscopy in a frequency range [100-10
6
 Hz] and temperature range [150−400 K] proves the appearance of the relaxation process in the modulus spectra after Sr substitution. The dc conductivity shows a VRH conduction process for both samples at lower temperatures and an SPH one at higher temperature with an increase in the activation energy for BT material and a decrease in the BST one. The ac conductivity data were described by Jonscher’s power law indicating a correlated barrier hopping (CBH) conduction process in the BT sample and an overlapping large polaron tunneling (OLPT) one for the BST compound.