Percolated perpendicular medium of FePt‐MgO/MgO bilayer films for ultra‐high magnetic recording

Percolated perpendicular (FePt) 100–x ‐(MgO) x thin films with x = 0–10.07 vol.% were fabricated on glass substrate with MgO(200)underlayer. When the substrate temperature was 580 o C, a significant enhancement in coercivity was observed at 1.23 vol.% of MgO, which was due to the precipitation of MgO in FePt film causing the hindrance in domain wall motion. As the amount of MgO was increased above 1.23 vol.%, the percolated perpendicular structure began to transform into granular perpendicular structure. Meanwhile, the MgO was found to segregate along grain boundaries of FePt grains, leading to the reduction of FePt grain size. As a result the coercivity and ordering parameter became smaller. In this study the percolated perpendicular medium using FePt film with doping adequate amount of MgO has shown possibility to be an efficient method to increase recording density if the film processing conditions are optimized further. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)