Magnetic properties of water-based sol-gel derived BaFe12O19/SiO2/Si(100) thin films

Thin films with barium hexaferrite (BaM) layers on thermally oxidized silic on wafers were fabricated by water-based sol-gel method. Polycrystalline Ba Fe12O19/SiO2/Si(100) thin films were characterized with Rutherford backscat tering, x-ray diffraction, vibrating sample magnetometer, and atomic force microscope as well as Fourier transform infrared spectroscopy (FT-IR). The thin films were annealed at 600-900 degreesC in air for 2 hours. The patter n for the sample annealed at a temperature above 650 degreesC indexed well on the M-type hexagonal structure and no other phases were detectable. The films were composed of uniformly distributed hexagonal-type grains, with di ameters between 400 and 600.. Surface roughness of the films was between 20 and 40 Angstrom . The perpendicular coercivity H-C perpendicular to and in -plane one H-C// were 4766 Oe and 4480 Oe, respectively, at room temperatur e under an applied field of 10 kOe annealed at 650 degreesC for 2 hours.