Patent ID: 7384699

Claim:
A magnetic recording medium with tuned exchange coupling, comprising: a non-magnetic substrate having a surface; a stack of thin film layers on said surface of said substrate, said layer stack including: an hcp Ru-alloy underlayer with an hcp <0001> preferred growth orientation; an exchange decoupled magnetic layer comprising magnetic grains or particles overlying said underlayer, said exchange decoupled magnetic layer is compositionally segregated and grown on said underlayer with an hcp <0001> preferred growth orientation, comprises a Co—Pt magnetic alloy including at least one other non-magnetic element, said magnetic grains or particles contain relatively higher concentrations of Co and Pt than boundaries of said exchange decoupled magnetic layer, and said boundaries of said exchange decoupled magnetic layer contain relatively higher concentrations of at least one other non-magnetic element and a relatively lower concentration of Co than said magnetic grains or particles, and are substantially non-magnetic; and an exchange coupled magnetic layer adjacent to said exchange decoupled magnetic layer and formed in direct physical contact therewith, said exchange coupled magnetic layer has an hcp <0001> preferred growth orientation, comprises a Co—Pt alloy with >˜15 at. % Pt, has a less compositionally segregated microstructure than said exchange decoupled magnetic layer, and boundaries thereof contain relatively lower concentrations of at least one other non-magnetic element and Co than other portions of said exchange coupled magnetic layer.