Relationship between structural and dielectric properties of Zn-substituted Ba5CaTi2−xZnxNb8O30 tetragonal tungsten bronze

Ba5CaTi2−xZnxNb8O30 ceramics (x = 0, 0.04, and 0.08) were synthesized by a conventional solid-state reaction method at 1300 °C for 6 hours. The effects of the Ti/Zn ratio on structural and dielectric properties were studied by changing the value of x. The pure phase formation of all prepared Ba5CaTi...

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Bibliographic Details
Published in:CrystEngComm 2021-01, Vol.23 (1), p.163-173
Main Authors: Bendahhou, Amine, Marchet, Pascal, El-Houssaine, Ablouh, Soufian El Barkany, Abou-Salama, Mohamed
Format: Article
Language:English
Subjects:
Ceramics
Crystal structure
Dielectric properties
Grain size
Phase transitions
Porosity
Rietveld method
Room temperature
Sinterability
Tungsten bronze
Zinc
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Summary:Ba5CaTi2−xZnxNb8O30 ceramics (x = 0, 0.04, and 0.08) were synthesized by a conventional solid-state reaction method at 1300 °C for 6 hours. The effects of the Ti/Zn ratio on structural and dielectric properties were studied by changing the value of x. The pure phase formation of all prepared Ba5CaTi2−xZnxNb8O30 compositions was confirmed by X-ray diffraction. The refinement of the (XRD) data by the Rietveld method confirmed the tetragonal crystal structure with the space group P4bm at room temperature. Scanning electron microscopy (SEM) showed that the Ba5CaTi2−xZnxNb8O30 ceramics have good sinterability, low porosity and uniform distribution of grains of unequal size over the entire surface in all the samples. The average grain size is in the range of 1.3 to 1.6 μm. The frequency-dependent dielectric properties were examined by complex impedance spectroscopy in the temperature range of 50 °C to 420 °C where a structural phase transition was observed for all the samples.
ISSN:1466-8033
DOI:10.1039/d0ce01561j