Structural and magnetic properties of HCP-CoCrPt-SiO2 granular media

Granular HCP-(CoCrPt)(100-x)(SiO2)(x) thin films with Cr underlayers have b een fabricated by sputtering multilayers followed by post-deposition anneal ing. Magnetic and structural properties of the films for potential applicat ions in magnetic recording media have bern investigated in detail. In as-de posited films coercivities exceeding 2.5 kOe have been obtained with SiO2 v arying from 8 to 16 vol%; high coercivity of 5.6 kOe and anisotropy of 4.6 x 10(6) erg/cm(3) have been achieved at low M(r)t value (about 0.4 memu/cm( 2)) in the post-annealed films. VSM measurements showed that the magnetic m oment lies well in the film plane under proper preparation conditions. Grai n isolation in the magnetic layer was improved by segregating SiO2 into gra in boundaries and further enhanced by post-deposition annealing. The rapid increase of the coercivity upon annealing is most likely due to the signifi cant decrease in intergranular exchange coupling, as shown by the deltaM me asurement in which the peak value of deltaM curves changed from a positive value to a negative value upon annealing. Magnetic reversal properties of t he films have also been systematically studied. These results show that the HCP-CoCrPt-SiO2 granular film is a promising candidate for ultra-high-dens ity recording media up to 100 Gbit/in(2) or beyond because of its low Pt co ntent and desirable properties. (C) 2001 Elsevier Science B.V. All rights r eserved.