Relationships between crystalline structure and dielectric properties in Sr2Sm(1-x)NdxTi2Nb3O15 ceramics
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| 1. | Title | Title of document | Relationships between crystalline structure and dielectric properties in Sr2Sm(1-x)NdxTi2Nb3O15 ceramics |
| 2. | Creator | Author's name, affiliation, country | k. chourti; Morocco |
| 2. | Creator | Author's name, affiliation, country | P. Marchet; France |
| 2. | Creator | Author's name, affiliation, country | Y. El Hafiane; France |
| 2. | Creator | Author's name, affiliation, country | A. Bendahou; Morocco |
| 2. | Creator | Author's name, affiliation, country | S. El Barkany; Morocco |
| 2. | Creator | Author's name, affiliation, country | M. Karroua; Morocco |
| 2. | Creator | Author's name, affiliation, country | M. Abou-salama; Morocco |
| 3. | Subject | Discipline(s) | |
| 3. | Subject | Keyword(s) | Tetragonal tungsten bronze; crystalline structure; X-ray diffraction; dielectric properties |
| 4. | Description | Abstract | In this study, tungsten-bronze type materials of Sr2Sm(1-x)NdxTi2Nb3O15 composition (x=0; 0,25; 0,5; 0,75 and 1) were elaborated by classical solid-state reaction. The structural characterization demonstrate that these compounds present tetragonal symmetry, using two space groups P4bm (N°100) and P4/mbm (N°127) respectively. The lattice parameters are a=b≈12,2Ǻ; c≈3,8Ǻ; V≈579,03Ǻ and Z=2. In this compounds, Ti and Nb cations show obvious off-center displacements along the c axis in both the Ti/Nb(1)O6 and the Ti/Nb(2)O6 octahedra. Besides, the unequal Ti/Nb(2)–O bonds length in the equatorial plane of Ti/Nb(2)O6 octahedra indicates the displacement of the Ti/Nb(2) cations in the ab plane, and no displacement of the Ti/Nb(1) cations exists in the ab plane. The results show that this material has two types of octahedral, first octahedron with little deformation around the Ti1/Nb1 and the second octahedron are more distorted around the Ti2/Nb2. The measurements of permittivity and dielectric losses of the ceramic samples performed between 25°C and 700°C (100Hz to 1MHz), high dielectric constants (εr=127 ~ 194) and low dielectric losses (tan(δ) around 10-4 at 1MHz) were found. The maximum value of the dielectric constant is obtained for x=0 (εr=194). The Curie temperature Tc decreases from 332 to 246°C as a function of the substitution of the samarium by neodymium. Detailed microstructural analysis by scanning electron microscope (SEM) and (EDS) for this compounds are also investigated. |
| 5. | Publisher | Organizing agency, location | |
| 6. | Contributor | Sponsor(s) | Pascal Marchet,Science of Ceramic Processes and Surface Treatments (SPCTS),University of Limoges |
| 7. | Date | (YYYY-MM-DD) | 01-02-2020 |
| 8. | Type | Status & genre | Peer-reviewed Article |
| 8. | Type | Type | |
| 9. | Format | File format | |
| 10. | Identifier | Uniform Resource Identifier | https://revues.imist.ma/index.php/morjchem/article/view/18479 |
| 10. | Identifier | Digital Object Identifier (DOI) | https://doi.org/10.48317/IMIST.PRSM/morjchem-v8i1.18479 |
| 11. | Source | Title; vol., no. (year) | Moroccan Journal of Chemistry; Vol 8, No 1 (2020) |
| 12. | Language | English=en | en |
| 13. | Relation | Supp. Files | |
| 14. | Coverage | Geo-spatial location, chronological period, research sample (gender, age, etc.) | |
| 15. | Rights | Copyright and permissions |
Copyright (c) 2020 Moroccan Journal of Chemistry |