Abstract:

The new nanocrystallites of the pyrochlore-type of rare earth complex oaldes with B-site doped,RE₂Sn_2-xB'_xO₇(RE=Sm,Ce; B'=Fe,Co,Ni: x=0～1-0), were prepared by unalcolate sol-gel method forthe first time. The nanocrystallite sizes were from 25 to 3Onm. It is found that this method can lowerreactive temperature (about 200℃) and shorten reactive time, The crystal structure of the nanocrystallitesbelongs to.cubic system and their lattice parameters are linear1y related to the content of doped ions. FromIR spectra, it is found that:(1) the data of absorption frequency of samples with RE=Ce are lower than that of with RE=Sm; (2) dopants of different ions in B-site not only bring about distortion of BO₆ octahedron, presenting relevant absorption, but also affect the vibration of RE--O bridge, causing lower frequency.

Key words: rare carth complex oxides, nanocrystallites, crysta1 structure, IR spectra