Size dependent compressibility of nano-ceria: Minimum near 33 nm

Rodenbough P. P., Song J., Walker D., Clark S. M., KALKAN B., Chan S.

APPLIED PHYSICS LETTERS, vol.106, no.16, 2015 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 106 Issue: 16
  • Publication Date: 2015
  • Doi Number: 10.1063/1.4918625
  • Journal Name: APPLIED PHYSICS LETTERS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Hacettepe University Affiliated: Yes

Abstract

We report the crystallite-size-dependency of the compressibility of nanoceria under hydrostatic pressure for a wide variety of crystallite diameters and comment on the size-based trends indicating an extremum near 33 nm. Uniform nano-crystals of ceria were synthesized by basic precipitation from cerium (III) nitrate. Size-control was achieved by adjusting mixing time and, for larger particles, a subsequent annealing temperature. The nano-crystals were characterized by transmission electron microscopy and standard ambient x-ray diffraction (XRD). Compressibility, or its reciprocal, bulk modulus, was measured with high-pressure XRD at LBL-ALS, using helium, neon, or argon as the pressure-transmitting medium for all samples. As crystallite size decreased below 100 nm, the bulk modulus first increased, and then decreased, achieving a maximum near a crystallite diameter of 33 nm. We review earlier work and examine several possible explanations for the peaking of bulk modulus at an intermediate crystallite size. (C) 2015 AIP Publishing LLC.