Epitaxial barium hexaferrite on sapphire by sputter deposition

Epitaxial films of barium hexaferrite (BaFe12 O19 ) have been prepared on basal-oriented sapphire substrates by rf sputter deposition of an amorphous ferrite film and crystallization of the film by annealing. Liquid phase epitaxy has been used to deposit an additional barium hexaferrite layer on top of the sputter deposited and annealed film. In this way films having symmetric ferromagnetic resonance peaks as narrow as 41 Oe at 60 GHz have been obtained.