Containing an AITa or AITi pre-seed layer, a CoCr onset layer and a CoCrPtB magnetic layer

A disk drive comprising:

• a motor for rotating a spindle;
• a thin film magnetic disk mounted on the spindle;
• an actuator assembly including a head for writing magnetic information on the disk as it rotates, wherein said thin film disk includes:
• a substrate;
• a pre-seed layer with an amorphous or nanocrystalline structure, said pre-seed layer being comprised of AlTa or AlTi;
• a non-magnetic ruthenium-aluminum (RuAl) seed layer deposited over the pre-seed layer;
• at least one non-magnetic underlayer deposited over the RuAl layer;
• at least one onset layer deposited over the underlayer, wherein said onset layer is comprised of CoCr and wherein the concentration of Cr is in the range of 28-33 at. %;
• and
• at least one magnetic layer deposited over the onset layer, wherein said magnetic layer is comprised of CoPtxCrBy, wherein x is the at. % concentration of Pt, y is the at. % concentration of boron, and x>4+7.

A method of manufacturing a thin film magnetic disk comprising the steps of:

• depositing a pre-seed layer with an amorphous or nanocrystalline structure onto a substrate, said pre-seed layer being comprised of AlTa or AlTi;
• depositing a crystalline ruthenium-aluminum (RuAl) seed layer over the pre-seed layer;
• depositing at least one non-magnetic underlayer over the RuAl seed layer;
• depositing at least one onset layer over the underlayer, wherein said onset layer is comprised of CoCr and wherein the concentration of Cr is in the range of 28-33 at. %;
• and
• depositing at least one magnetic layer over the onset layer, wherein said magnetic layer is comprised of CoPtxCrBy, wherein x is the at. % concentration of Pt, y is the at. % concentration of boron, and x>4+y.