Hexaferrite particles prepared by sol-gel technique

The chemical sol-gel route is used to prepare undoped and substituted barium and strontium ferrites. Beside standard crystallographic and magnetic measurements, ferromagnetic resonance experiments are used to analyze the formation of the hexaferrite phase and to determine the anisotropy field strength. Specific saturation magnetization, coercive and anisotropy field strength are determined depending on the heat treatment of the gel and the ion-ratio in the starting sol. The special preparation conditions and the magnetic properties of sol-gel derived [Ba,Sr]Me/sub x//sup 2+/Ti/sub x//sup 4+/Fe/sub 12-2x/O/sub 19/ with Me/sup 2+/=Zn/sup 2+/,Co/sup 2+/ and x=0-1.0 are discussed. Additionally, the typical morphology of the investigated powders is underlined by REM- and TEM-photographs.