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Séminaire MCMF

Jeudi 31 janvier à 14h30

Orateur : Silvania Lanfredi

"Discovering New Properties and Engineering Old Properties in Semiconductor-Ferroelectric Niobates with Tetragonal Tungsten Bronze TTB-Type structure"


Crystals of niobates with a tetragonal tungsten bronze (TTB)-type structure are of great technical, scientific, and industrial interest as optic materials for laser modulation, frequency multiplicity, the generation of second harmonics and for applications in pyroelectric detectors and piezoelectric transducers. Some of them with TTB-type structure are also important for microwave telecommunications involving satellite broadcasting. Actually, polycrystalline niobates with TTB-type structure exhibiting high anisotropy of the crystalline structure, conformational polyhedral and unconventional niobium defect have shown further potential, allowing that these materials reach new frontiers. Semiconductor character and ferroelectric Curie temperature has understood. Electric conduction, Curie temperature, temperature of phase transition, phase transition suppression phenomenon can now be engineered. From recent advances on the microchemistry of defects, the correlation between the structural and electrical, dielectrical properties of several alkaline niobates of TTB-type structure has been advanced leading to discover of new properties at inner shell (chemical sensor) and surface (catalysts) of particles.

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