X-ray structural studies on solubility of Fe substituted CuO

Abstract

CuO is a promising material for the spintronic industry for which lattice distortions/defects play an important role in determining its magnetic and various other physical properties. The ionic radii and charge of Cu²⁺[VI] (0.73 Å) and Fe³⁺[VI] (0.64 Å) are quite different. Hence high Fe substitution in CuO in place of Cu may generate strain/distortions. Fe substitution may enhance magnetic properties, even at room temperature, making such materials interesting for device applications. A detailed structural study on Fe incorporated CuO lattices to confirm phase purity, supported by evidence of the absence of a secondary phase is absolutely essential especially when considering a considerable substitution of up to ∼12.5%. The electronic valence state, fine structure and local neighborhood/geometry of constituent elements need to be investigated using synchrotron based X-ray absorption spectroscopy (XAS). We report, for the first time, such a detailed study on understanding this magnetically and electronically important material: Cu_1−xFe_xO, 0 ≤ x ≤ 0.125.