The dependence of cation distribution, microstrain and magnetic susceptibility on particle size in nanocrystalline Gd<inf>2</inf>O<inf>3</inf>/Y<inf>2</inf>O<inf>3</inf>

Abstract

A novel synthesis route based on thermal decomposition of yttrium and gadolinium complexes with 2,4-pentanedione ligand has been used to synthesize 5 nm size (Y0.9Gd0.1)2O3 powder. Refinement of occupancy parameters revealed that Gd3+ ions preferably occupy C3i sites in host Y2O3, forming a material with a metastable cation distribution. The average crystallite size was found to increase, and the average microstrain to decrease, as the annealing temperature is increased, while the Gd3+ ion distribution remained metastable in nature. Small anisotropic X-ray powder diffraction pattern line broadening due to crystallite size effects was observed. The inverse susceptibility of the 5 nm sample exhibits unusual break in slope to a smaller value below 2.7 K. © 2007 Acta Materialia Inc.