ISSN 0004-881X

Pressure-Induced Polyamorphic Transition in Nanoscale TiO₂

by Varghese Swamy and Barry C. Muddle

Department of Materials Engineering, Monash University, Victoria 3800, Australia

Abstract

The detection and characterization of pressure-induced amorphization in <10-nm-sized anatase TiO2 nanocrystals at pressures >20 GPa and ambient temperature is documented. The characterization employed in situ high-pressure angle-dispersive synchrotron X-ray diffraction and Raman spectroscopy in diamond-anvil cells. Comparative Raman spectroscopy allows the local structures of the high-density amorphous (HDA) form obtained at high pressures and its low-pressure (<10-15 GPa) low-density amorphous (LDA) analogue to be related to the baddeleyite-TiO2 and TiO2-II structures, respectively. The pressure-induced amorphization and the HDA-LDA transition in nanoscale TiO2 bear broad similarities to transitions in the Si and H2O systems.

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