Zhejiang Univ, Dept Mat Sci & Engn, Lab New Struct Mat, Hangzhou 310027, Peoples R China
; Zhejiang Univ, Ctr Anal, Hangzhou 310028, Peoples R China
; Zhejiang Sci Tech Univ, Ctr Anal, Hangzhou 310018, Peoples R China
; Chinese Acad Sci, Inst High Energy Phys, Beijing, Peoples R China
; Res Ctr Karlsruhe, Inst Nanotechnol, D-76021 Karlsruhe, Germany
High-pressure behaviors of bulk and nanocrystalline SnO2 samples have been studied by in situ high-pressure synchrotron radiation x-ray diffraction measurements up to about 40 GPa at ambient temperature. It is found that the smaller the nanocrystal SnO2, the higher the onset transition pressure for the rutile-to-cubic phase transformation in SnO2. The enhancement of the transition pressure is mainly due to the surface energy differences between the rutile and cubic phases and/or the enhancement of energy band gap when the SnO2 crystallite size gets smaller.