Investigations of zero-field splitting (ZFS) and local distortion parameters of Fe3+ ions doped into three oxi-spinels (ZnAl2O4, MgAl2O4, and ZnGa2O4) by theoretical analysis

The local environment around the paramagnetic centers formed by the Fe3+ ions doped into three oxi-spinel crystals (ZnAl2O4, MgAl2O4, and ZnGa2O4) is investigated utilizing the fourth-order perturbation formula of the axial zero-field splitting parameter D on the basis of the dominant spin–orbit coupling mechanism. In order to fix a plausible cubic space group for B-sites located by Al3+/Ga3+ cations, several modeling approaches are used and the results are discussed in detail.

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► In this study we investigated the local environment around the paramagnetic centers formed by the Fe3+ ions doped into three oxi-spinel crystals (ZnAl2O4, MgAl2O4, and ZnGa2O4).
► We revealed that Fe3+ ions can easily replace Al3+/Ga3+ sites attributing D3d site symmetry with considerably small structural distortion parameters ΔR and Δθ in ZnAl2O4 and ZnGa2O4 crystals whereas Fe3+ ions can replace Al3+ sites attributing either D3d or C3v site symmetries with minor ΔR and Δθ in the structure of MgAl2O4.
► The results has the potential to be source materials for the future experimental (e.g. EPR) and theoretical studies.