Péter Szirmai, Endre Horváth, Bálint Náfrádi, Zlatko Micković, Rita Smajda, Dejan M. Djokić, Kurt Schenk, László Forró, Arnaud Magrez
We report a novel synthesis route of homogeneously manganese doped titanium dioxide nanotubes in a broad concentration range. The scroll-type trititanate (H(2)Ti(3)O(7)) nanotubes prepared by hydrothermal synthesis were used as precursors. Mn2+ ions were introduced by an ion exchange method resulting Mn(x)H(2-x)Ti(3)O(7). In a subsequent heat-treatment they were transformed into Mn(y)Ti(1-y)O(2) where y=x/(3+x). The state and the local environment of the Mn2+ ions in the precursor and final products were studied by Electron Spin Resonance (ESR) technique. It was found that the Mn2+ ions occupy two positions with cubic and strongly distorted tetrahedral local symmetries. The ratio of the two Mn2+ sites is independent of the doping level and amounts to 15:85 in Mn(x)H(2-x)Ti(3)O(7) and to 5:95 in Mn(y)Ti(1-y)O(2). SQUID magnetometry does not show long range magnetic order in the homogeneously Mn2+ doped nanotubes.
View original:
http://arxiv.org/abs/1211.3459
No comments:
Post a Comment