Evidence of a cubic iron sub-lattice in t-CuFe2O4 demonstrated by X-ray Absorption Fine Structure

Copper ferrite, belonging to the wide and technologically relevant class of spinel ferrites, was grown in the form of t-CuFe 2 O 4 nanocrystals within a porous matrix of silica in the form of either an aerogel or a xerogel, and compared to a bulk sample. Extended X-ray absorption fine structure (EXAFS) spectroscopy revealed the presence of two different sub-lattices within the crystal structure of t-CuFe 2 O 4 , one tetragonal and one cubic , defined by the Cu 2+ and Fe 3+ ions respectively. Our investigation provides evidence that the Jahn-Teller distortion, which occurs on the Cu 2+ ions located in octahedral sites, does not affect the coordination geometry of the Fe 3+ ions, regardless of their location in octahedral or tetrahedral sites.