Magnetic properties of Co/sub 2/Y-type hexaferrite particles oriented in a rotating field

Cobalt Y-type hexaferrites are of interest as high permeability (mu) materials in the miniaturization of integrated circuits. We oriented particles of sintered Co/sub 2/Y-type hexaferrite with c-axis normal to the slab plane. We measured the magnetic properties of Co substituted Y-type hexaferrites (Co/sub 0.25/Zn/sub 1.75/Y and Mn/sub 0.25/Co/sub 0.75/Zn/sub 1.0/), where the substitutions included Mn and Zn. The uniaxial magnetic anisotropy field, H/sub A/, decreased from 42 to 14.5 kOe as Zn substitution increased at the expense of Co. The ferromagnetic resonance linewidth exhibited similar dependence on Zn substitution varying from 1500 to 200 Oe at 28 GHz. For all the Zn or Mn substitutions, the saturation magnetization was relatively constant at 2000 G.