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High-pressure and high-temperature synthesis of the cubic Ti O 2 polymorph

2004; American Physical Society; Volume: 70; Issue: 21 Linguagem: Inglês

10.1103/physrevb.70.212101

1550-235X

Maurizio Mattesini, J. S. de Almeida, Leonid Dubrovinsky, Natalia Dubrovinskaia, B. Johansson, Rajeev Ahuja,

Crystal Structures and Properties

We report on an in situ observation of a cubic titanium dioxide polymorph. Experiments conducted on an anatase sample as starting material using a laser-heated diamond-anvil cell have shown that at a pressure of $48\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$ and temperatures between 1900 and $2100\phantom{\rule{0.3em}{0ex}}\mathrm{K}$, the x-ray diffraction pattern contains reflections of two phases: the known cotunnite-structured $\mathrm{Ti}{\mathrm{O}}_{2}$ and the new cubic phase with lattice parameter $a=4.516(1)\phantom{\rule{0.3em}{0ex}}\mathrm{\AA{}}$. Reflections of the cubic phase can be followed on decompression at ambient temperatures down to about $9\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$. Our observations suggest that at high temperature and elevated pressure both IV $AB$ and IV $A$ element dioxides follow a common transformation path.