  Single-domain particles of SrFe8Al4O19 were prepared by thermal treatment at
1473 K of porous products of citrate-nitrate auto-combustion, and the influence
of synthesis time on the particle morphology and magnetic properties was
studied. The procedure allows to obtain SrFe8Al4O19 particles with mean
diameters 100 - 460 nm, and their coercivity ranges from 14.5 to 18.4 kOe,
while ferromagnetic resonance frequencies vary from 149 to 164 GHz.
