No abstract

No abstract

No abstract

No abstract

Low noise perpendicular magnetic recording hard disk using an amorphous soft magnetic CoZrNb underlayer, has been developed. Soft magnetic layer is prepared by the depositing materials on the disk substrates in the magnetic field directed radially by the magnets in a DC magnetron sputtering system. CoZrNb underlayer with magnetic easy axis uniform in the radial direction is more easily producible than a permalloy underlayer on the glass substrate. Perpendicular recording layer with high crystal orientation (A850 ~ 3°) is also obtained by sputtering CoCrTa on the fresh surface of the CoZrNb underlayer. On the glass substrate, remarkably lower medium noise and a higher SNR are achieved with the CoZrNb under layer than with the permalloy underlayer. This noise reduction is mainly due to the uniformity of magnetic easy axis in the CoZrNb underlayer.