鈷/鉑多層薄膜與鈷鉑合金膜之製備與性質研究

Abstract

Co/Pt multilayers and alloy films with large perpendicular anisotropy have been fabricated, and the correlations between their magnetic/magneto-optic properties and microstructures were investigated. A disk made of the CoPt alloy film was characterized for the feasibi-lity as a media of magneto-optic recording.Co/Pt multilayers were prepared by evaporation and sputter methodswith dual-guns. The layered structure was manifested by low angle x-ray diffraction. The highest perpendicular anisotropy was obtained inthe films of Co thickness ~3A.ZnO and Ga2O3 underlayers enhanced effectively the coercivity of Co/Ptmultilayers. The dependence of the measured coercivity on the columnsize (characterized by AFM) was interpreted based on a model of magne-tically independent columnar particles. The annealing effects on magnetic properties were also studied.CoPt alloy films grown at the optimized conditions, 200~250oC with Cocontents 25%, exhibited perpendicular coercivity ~2.4 KOe and a saturated remanence. By TEM analysis, the major defects detected inthe films were twins and the highest concentration of twins was foundin the optimized sample. Assuming the partial ordering of CoPt3, twins and Co-Co pairs, induced anisotropy normal to twins-plane was evalu-ated by a Pair model.Disk coated with the CoPt alloy films was tested, using a laser sourceof wavelength 680 nm, at 1 MHz recording frequency and 10 M/s velocity, CNR~45 dB was obtained with a recording power ~10mW and external field ~300Oe.