Compressibility and structural behavior of pure and Fe-doped SnO2 nanocrystals

Abstract We have performed high-pressure synchrotron X-ray diffraction experiments on nanoparticles of pure tin dioxide (particle size ∼30 nm) and 10 mol % Fe-doped tin dioxide (particle size ∼18 nm). The structural behavior of undoped tin dioxide nanoparticles has been studied up to 32 GPa, while the Fe-doped tin dioxide nanoparticles have been studied only up to 19 GPa. We have found that both samples present at ∼13 GPa a second-order structural phase transition from the ambient pressure tetragonal rutile-type structure ( P4 2 /mnm ) to an orthorhombic CaCl 2 -type structure (space group Pnnm ). No phase coexistence was observed for this transition. Additionally, pure SnO 2 presents a phase transition to a cubic structure at ∼24 GPa. The evolution of the lattice parameters with pressure and the room-temperature equations of state are reported for the different phases. The reported results suggest that the partial substitution of Sn by Fe induces an enhancement of the bulk modulus of SnO 2 . Results are compared with previous studies on bulk and nanocrystalline SnO 2 . The effects of pressure on Sn-O bonds are also analyzed.