NONEPITAXIAL SPUTTER SYNTHESIS OF ALIGNED STRONTIUM HEXAFERRITE, SRO.6(FE2O3), FILMS

Films of strontium hexaferrite were synthesized through rf diode sputt er deposition, nonepitaxially onto polycrystalline Al2O3 substrates. S o far such films for the analogous Ba phase have been synthesized most ly through epitaxial growth onto suitably chosen matching substrates. Crystallization of the strontium hexaferrite phase was achieved for de position temperatures as low as 500-degrees-C. For nonepitaxially synt hesized 2-3-mum-thick polycrystalline films, a fairly high degree of v ariable and controlled c-axis orientation of the crystallites has been obtained. The x-ray-diffraction traces of films with a strong c-axis in-plane alignment showed predominantly (110)-type reflections. The fi lm coercivities were increased by postdeposition annealing in O2. The remnant to saturation flux density ratio of such in-plane anisotropy f ilms for in-plane measurements was 0.62, with an in-plane coercivity a lmost-equal-to 2.3 kOe.