CGC perpendicular recording media with CoCrPt-SiO2 alloy as granular layer

We investigated a new class of coupled granular/continuous (CGC) perpendicular media consisting of CoCrPt-SiO₂ granular layer with magnetically decoupled small grains. By changing the number of Co/Pd bi-layers in the continuous layer, the degree of exchange coupling can be systematically controlled. The introduction of Co/Pd multilayer improved the nucleation field (H_n) from —570 to —1670 Oe and K_uV/k_BT values from 67 to 97. Compared to the base granular media, the CGC media had 1 dB gain in signal-to-noise ratio (SNR) as well as 14 dB gain in write-ability (OW). Moreover, the output decay was reduced from —0.11 to—0.035 dB per decade. In CGC approach, a more appropriate strength of exchange coupling can be introduced that yields the significant improvement in both SNR and thermal stability.