A technique for evaluating track deviation at nanometer-scale accuracy

A technique for evaluating track deviation in magnetic disk drives has been developed. The technique uses an external position sensor and an error cancellation sequence, and enables measurement of track-to-track spacing. The resolution of track position is less than 2 nm. The repeatability is less than 5 nm. The technique helps reveal track alignment error, which needs to be reduced to achieve over-100-KTPI recording.