High frequency dielectric relaxation in BaTio3derived materials
Abstract A systematic study of the dielectric relaxation phenomenon has been carried out for ceramics with compositions derived from barium titanate in the frequency and temperature ranges 1 MHz–1 GHz and 250–500 K, respectively. Whatever the composition may be, a minimum of the relaxation frequency and a maximum of the dielectric dispersion appears at each phase transition temperature. The dipole-type relaxation is correlated to coherent displacements of the ions in the octahedron sites ordered either along chains or in 3D-lattice.
Ferroelectric-based nanocomposites : towards multifunctional materials
Nanoparticle technologies open the routes for nanostructured materials which combine individual physical properties or generate new functions. In the field of ferroelectric materials the development of dense nanocomposites requires breakthroughs in the elaboration step. Here, we propose a flexible process to obtain ferroelectric−magnetic nanostructured materials using the assembly of superparamagnetic nanoparticles around ferroelectric cores. The appropriate shaping and sintering of these nanocomposites called nanoraspberries enables a tuning of the physical properties of the resulting dense composite: coexistence between ferroelectricity, piezoelectricity, and superparamagnetism is clearl…
Les céramiques pour l’électronique et l’électrotechnique
International audience; Ce chapitre est consacré au très vaste domaine des céramiques pour l’électronique et l’électrotechnique : céramiques résistives, conductrices, supraconductrices, diélectriques, magnétiques, linéaires ou non linéaires, piézoélectriques, multifonctionnelles. En perpétuelle évolution: de plus en plus petites, de moins en moins chères, de plus en plus intégrées…