CGC Perpendicular Recording Media With CoCrPt-SiO$_2$Alloy as Granular Layer

Abstract

We investigated a new class of coupled granular/continuous (CGC) perpendicular media consisting of CoCrPt-SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> 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 <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</sub> ) from -570 to -1670 Oe and K <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">u</sub> V/k <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">B</sub> T 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