Title :
Thermal stability of Co80Pt20-SiO2 granular films sputtered on DC pulse biased substrates
Author :
Xu, B. ; Zhou, J.N. ; Du, J. ; Barnard, J. ; Doyle, W.D.
Author_Institution :
Dept. of Phys. & Astron., Alabama Univ., Tuscaloosa, AL, USA
fDate :
9/1/2000 12:00:00 AM
Abstract :
Granular Co80Pt20-SiO2 films have been prepared with thicknesses of ~15 nm using a novel pulsed dc bias technique. This enabled the growth of thermally stable films with coercivities as high as 2.3 kOe without annealing. The CoPt granules are randomly oriented with a slight (1010) texture with diameters of 5-10 nm at 51% CoPt volume fraction. Measurement of the time-dependent coercivity was used to extract the value of intrinsic switching field Ho and the thermal stability factor KV/kT by fitting to Sharrock´s formula. The value of H0 decreases from 3.5 kOe at 41% CoPt to 2.5 kOe at 58% CoPt while KV/kT increases from 78 to a maximum of 236 at 56% CoPt before decreasing to 160 at 58% CoPt. The coercivity was relatively flat from 45% to 58% CoPt, presumably because of the offsetting effects of the increase in H0 and the decrease in KV/kT over this range
Keywords :
cobalt alloys; coercive force; ferromagnetic materials; granular materials; magnetic particles; magnetic switching; magnetic thin films; nanostructured materials; particle size; platinum alloys; silicon compounds; texture; thermal stability; (1010) texture; 15 nm; 5 to 10 nm; Co80Pt20-SiO2; Co80Pt20-SiO2 granular films; CoPt granules; DC pulse biased substrates; Sharrock formula; coercivities; growth; intrinsic switching field; pulsed dc bias technique; thermal stability; thermal stability factor; thermally stable films; thickness; time-dependent coercivity; volume fraction; Annealing; Coercive force; Conductive films; Magnetic anisotropy; Magnetic films; Magnetic recording; Magnetic separation; Perpendicular magnetic anisotropy; Substrates; Thermal stability;
Journal_Title :
Magnetics, IEEE Transactions on
