Magnetic coercivity patterns for magnetic recording on patterned media

An overview is given of a type of magnetic servo pattern made by locally altering the magnetic coercivity of a perpendicular anisotropy film where the FIB-irradiated areas are permanently defined and easily recovered in their exact positions by applying a uniform magnetic field. The generated magnetic pattern can be integrated as a servo pattern along with the data pattern, which allows single patterned media bits to be written with positioning accuracy of better than 10 nm, well below the lithographic resolution and sensor track width.