抄録
Co2Z type hexagonal Ba ferrite Ba3Co2Fe24O41 is a candidate material for micro-wave absorbers in GHz band because of its high permeability. Ba3Co2Fe24O41 was prepared under various oxygen partial pressures (21.3, 61.3 and 101.3 kPa) at 1573 K by a conventional ceramics process. To examine the effect of sintering oxygen partial pressure on their permeability, these three samples were characterized by techniques of magnetization measurement, X-ray diffraction and neutron diffraction.No evident difference in saturation magnetization of these samples was found.Arrangement of magnetic ions and orientation of the magnetic moments in the hexagonal crystal was refined by the neutron diffraction Rietveld analysis. The results show that cobalt ions occupy only specific five out of ten possible sites in any samples. It was found that the sample, in which the angle of magnetic moments against the basal hexagonal plane are smaller, has tendency of higher permeability.
