Niobiany ziem rzadkich – właściwości i zastosowania

Rare earth niobates are a very interesting group of materials. These compounds have different properties which could be changed in a wide range by appropriate doping. X-Ray diffraction examinations for some compounds of RE3NbO7 group were shown. All peaks agree with diffraction patterns. Phases from other elements are not reported. These materials were divided into three space groups depending on ionic radius of RE3+. The most important from applicational point of view is defected-fluorite type structure which is reached for the smallest RE3+ cations. Surface morphology made by Scanning Electron Microscopy was shown. The microstructure of examined materials varies grain size what is connected with ionic radius RE3+. Electrical measurements made in dry argon atmosphere show that the highest values of ionic conductivity were reached for two last lanthanides rare earth niobates Yb3NbO7, Lu3NbO7 and for Y3NbO7. Contained optical properties measurements show that Spark Plasma Sintering enables to obtain Lu3NbO7 which is transparent for visible light.