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Papers by AMINE BENDAHHOU
Moroccan Journal of Chemistry, 2020
In this study, tungsten-bronze type materials of Sr 2 Sm (1-x) Nd x Ti 2 Nb 3 O 15 composition (x... more In this study, tungsten-bronze type materials of Sr 2 Sm (1-x) Nd x Ti 2 Nb 3 O 15 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≈579,0 3 Ǻ 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)O 6 and the Ti/Nb(2)O 6 octahedra. Besides, the unequal Ti/Nb(2)–O bonds length in the equatorial plane of Ti/Nb(2)O 6 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 permi...
Journal of Alloys and Compounds, 2021
CrystEngComm, 2020
Ba5CaTi2−xZnxNb8O30 ceramics (x = 0, 0.04, and 0.08) were synthesized by a conventional solid-sta... more 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.
Materials Today: Proceedings, 2021
Abstract In the present work, we have studied the effect of Gd-substitution on the structural, di... more Abstract In the present work, we have studied the effect of Gd-substitution on the structural, dielectric and electrical properties of Sr2Sm1−xGdxTi2Nb3O15 (x = 0 and 0.5) tungsten bronze ceramics prepared by a high-temperature solid-state reaction technique. The formation of the phase of tetragonal tungsten bronze was verified by the Rietveld refinement using X-ray diffraction data. With increasing Gd concentration, the crystal structure of the Sr2Sm1−xGdxTi2Nb3O15 ceramics has slightly deformed from the tetragonal P4bm phase to the paraelectric P4/mbm phase. Scanning electron microscopy (SEM) of ceramics shows high densification and homogeneous distribution of grains of different sizes over the total surface. The crystallite size increases with Gd-substitution from 6.19 nm for Sr2SmTi2Nb3O15 to 10.83 nm for Sr2Sm0.5Gd0.5Ti2Nb3O15. The sample Sr2SmTi2Nb3O15 shows a dielectric anomaly of ferroelectric paraelectric type at 332 °C, and has non-relaxor type of diffuse phase transition. In addition, the dielectric properties deteriorated and even disappeared for the sample Sr2Sm0.5Gd0.5Ti2Nb3O15, because the ceramic presented a P4/mbm phase structure as a result of the decrease in Curie temperature (Tc) below room temperature. The electrical property of Sr2Sm1−xGdxTi2Nb3O15 ceramic has been investigated by non-destructive complex impedance spectroscopy (CIS) as a function of frequency at different temperatures.
RSC Advances
In this work, Zn co-doped tungsten bronze having nominal formula Ba5CaTi1.94Zn0.06Nb8O30has been ... more In this work, Zn co-doped tungsten bronze having nominal formula Ba5CaTi1.94Zn0.06Nb8O30has been synthesized and systematically studied for structure, dielectric and electrical properties.
Moroccan Journal of Chemistry, 2020
In this study, tungsten-bronze type materials of Sr 2 Sm (1-x) Nd x Ti 2 Nb 3 O 15 composition (x... more In this study, tungsten-bronze type materials of Sr 2 Sm (1-x) Nd x Ti 2 Nb 3 O 15 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≈579,0 3 Ǻ 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)O 6 and the Ti/Nb(2)O 6 octahedra. Besides, the unequal Ti/Nb(2)–O bonds length in the equatorial plane of Ti/Nb(2)O 6 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 permi...
Journal of Alloys and Compounds, 2021
CrystEngComm, 2020
Ba5CaTi2−xZnxNb8O30 ceramics (x = 0, 0.04, and 0.08) were synthesized by a conventional solid-sta... more 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.
Materials Today: Proceedings, 2021
Abstract In the present work, we have studied the effect of Gd-substitution on the structural, di... more Abstract In the present work, we have studied the effect of Gd-substitution on the structural, dielectric and electrical properties of Sr2Sm1−xGdxTi2Nb3O15 (x = 0 and 0.5) tungsten bronze ceramics prepared by a high-temperature solid-state reaction technique. The formation of the phase of tetragonal tungsten bronze was verified by the Rietveld refinement using X-ray diffraction data. With increasing Gd concentration, the crystal structure of the Sr2Sm1−xGdxTi2Nb3O15 ceramics has slightly deformed from the tetragonal P4bm phase to the paraelectric P4/mbm phase. Scanning electron microscopy (SEM) of ceramics shows high densification and homogeneous distribution of grains of different sizes over the total surface. The crystallite size increases with Gd-substitution from 6.19 nm for Sr2SmTi2Nb3O15 to 10.83 nm for Sr2Sm0.5Gd0.5Ti2Nb3O15. The sample Sr2SmTi2Nb3O15 shows a dielectric anomaly of ferroelectric paraelectric type at 332 °C, and has non-relaxor type of diffuse phase transition. In addition, the dielectric properties deteriorated and even disappeared for the sample Sr2Sm0.5Gd0.5Ti2Nb3O15, because the ceramic presented a P4/mbm phase structure as a result of the decrease in Curie temperature (Tc) below room temperature. The electrical property of Sr2Sm1−xGdxTi2Nb3O15 ceramic has been investigated by non-destructive complex impedance spectroscopy (CIS) as a function of frequency at different temperatures.
RSC Advances
In this work, Zn co-doped tungsten bronze having nominal formula Ba5CaTi1.94Zn0.06Nb8O30has been ... more In this work, Zn co-doped tungsten bronze having nominal formula Ba5CaTi1.94Zn0.06Nb8O30has been synthesized and systematically studied for structure, dielectric and electrical properties.