Study of electron transition energies between anions and cations in spinel ferrites using differential UV–vis absorption spectra

Abstract It is very important to determine electron transition energies ( E tr ) between anions and different cations in order to understand the electrical transport and magnetic properties of a material. Many authors have analyzed UV–vis absorption spectra using the curve ( αhν ) 2 vs E , where α is the absorption coefficient and E (= hν ) is the photon energy. Such an approach can give only two band gap energies for spinel ferrites. In this paper, using differential UV–vis absorption spectra, d α /d E vs E , we have obtained electron transition energies ( E tr ) between the anions and cations, Fe 2+ and Fe 3+ at the (A) and [B] sites and Ni 2+ at the [B] sites for the (A)[B] 2 O 4 spinel ferrite samples Co x Ni 0.7− x Fe 2.3 O 4 (0.0≤ x ≤0.3), Cr x Ni 0.7 Fe 2.3− x O 4 (0.0≤ x ≤0.3) and Fe 3 O 4 . We suggest that the differential UV–vis absorption spectra should be accepted as a general analysis method for determining electron transition energies between anions and cations.