Evidence of a cubic iron sub-lattice in t-CuFe(2)O(4) 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.