Perpendicular magnetic recording medium and apparatus including a soft magnetic layer, an at least 20 nm thick non-magnetic layer, and a 50-90 nm gap length

Granted: Dec 21, 2004 Filed: Aug 6, 2002

This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.