Computational and experimental study on the cation distribution of La-Cu substituted barium hexaferrites

The total energies and forces of the Ba0.5La0.5Fe11.5Cu0.5O19 structure were calculated using the density functional theory (DFT) and generalized gradient approximation (GGA). The calculations demonstrated that at 0 K, the magnetic ions Cu2+ preferentially occupy Fe3+ at the 4f(2)(0) and 4f(2)(1) configurations. For the site occupancy at the higher temperature (0-1500 K, except 0 K), we computed the formation probability of twenty inequivalent configurations using the Maxwell-Boltzmann statistical distribution. Correspondingly, the Cu2+ ions prefer to enter the 4f(2) and 2b sites, especially close to lanthanum layer. In order to confirm the computational conclusions, La-Cu substituted barium hexaferrites with the chemical formula of Ba1-xLaxFe12-xCuxO19 (x = 0.0, 0.1, 0.3, and 0.5), prepared by a conventional ceramic method, were investigated by the Raman spectra and Rietveld refinement of X-ray diffraction patterns (XRD). The experiments revealed that the Cu2+ ions are partitioned at the 2b and 4f(2) sites in the ratio of around 1:2. (C) 2016 Elsevier B.V. All rights reserved.