Fabrication, Magnetic, and R/W Properties of Nitrogen-Ion-Implanted Co/Pd and CoCrPt Bit-Patterned Medium

A method of making a cost-effective bit-patterned medium combining: 1) a pattern imprint; 2) ion doping; and 3) an ashing process is described. The Nitrogen ion was doped to change the magnetic properties of the Co/Pd and CoCrPt magnetic layer. The Nitrogen ion induces surface and lattice, and the exchange coupling strength changes during doping which suppress the magnetization and anisotropy of Co/Pd and CoCrPt magnetic layers. This can be achieved at relatively lower dosages so that a subsequent ashing process creates a smooth surface. The thermal stability of doped film and dot was good for practical applications. Monte-Carlo simulations were used to estimate the lateral ionic distribution within the dot region and compared with magnetic-force microscopy. To demonstrate this technique, areal densities of 134 Gb/in² on Co/Pd media and 250 Gb/in² on CoCrPt media are shown.