Cr-site preference of BaFe<inf>12-x</inf>Cr<inf>x</inf>O<inf>19</inf> hexaferrite ceramics monitored by Mössbauer spectroscopy

Abstract

Site preference of Cr in the M-type barium ferrite ceramics was monitored by powder X-ray diffraction (XRD), magnetization measurements and Mössbauer spectroscopy. The calcined BaFe12-xCrxO19 powders (x = 0.0-0.8) obtained by the sol gel method were die-pressed into pellets and then sintered at 1300°C in a oxygen atmosphere for 12 hrs. All the phases of the ceramics were of the pure magnetoplumbite structure. The saturation magnetization (Ms) is found to be a function of Cr ion content. The Ms of the ceramics decreases due to the dilution of the magnetic interaction with increasing Cr concentration. The coercivity (H c) of the ceramics increases due to finer grain observed by scanning electron microscopy (SEM). Fitted Mössbauer spectra show that Cr ions preferentially occupy into the 2a, 12k and 4f2 Fe crystallographic sites. © 2007 WILEY-VCH Verlag GmbH & Co. KGaA.