Magnetic and atomic structure parameters of Sc-doped barium hexagonal ferrites

Abstract

Scandium-doped M -type barium hexagonal ferrites of the composition Ba Fe12-x Scx O19 are well suited for low frequency microwave device applications such as isolators and circulators. A series of Sc-doped M -type barium hexagonal ferrite powders (x=0-1.2) were prepared by conventional ceramic processing techniques. The resulting powders were verified to be pure phase and maintain the nominal chemical stoichiometry by x-ray diffraction and energy dispersive x-ray spectroscopy, respectively. Static magnetic measurements indicated that both saturation magnetization and uniaxial magnetocrystalline anisotropy field decreased with increasing concentration of scandium. Extended x-ray absorption fine structure measurements were carried out to clarify the correlation between the magnetic and atomic structure properties. It is found that the substituted Sc has a strong preference for the bipyramidal site. Nevertheless, the substitution did not introduce additional atomic structural disorder into the barium hexagonal structure. The structural study provided important evidence to quantitatively explain the change in dc and microwave magnetic properties due to Sc ion doping. © 2008 American Institute of Physics.