Magnetic properties of polycrystalline Sr-M and Pb-M hexaferrites thin films grown by pulsed laser deposition on Si/SiO2 substrates

Pulsed laser ablation deposition has been used to grow polycrystalline Pb-M and Sr-M thin films with high coercivity on Si/SiO2 substrates. The influence of the substrate temperature (550-800DGC) and the oxygen pressure (1.0-3.0 mbar) on the magnetic properties during the deposition is discussed. The Pb-M hexaferrite thin films crystallise at the same temperature range as Sr-M thin films, but with inferior coercivities. In both cases, the best values of iHc (3.8 kOe, Pb-M films and 5.0 kOe for Sr-M thin film) are very close to the best value of sintered ceramic hexaferrite (5.0 kOe Pb-M and 6.0 kOe Sr-M). The isotropic character of the films was confirmed by a Mr/Ms behaviour near to 0.5.