Perpendicular magnetic recording medium and method of manufacturing it

A method of manufacturing a perpendicular magnetic recording medium having a recording layer provided on a substrate via an underlayer, including the steps of:

• forming a metal layer at a time of forming said underlayer;
• and
• forming an oxide layer with an average thickness greater than 0 nm to 0.2 nm or less.

A perpendicular magnetic recording medium having a recording layer provided on a substrate via an underlayer, wherein

• said recording layer is comprised of crystal grains consisting essentially of Co and Pt or Pd and a grain boundaries consisting of non-magnetic elements and oxygen,
• in those elements which constitute said grain boundaries, an amount of content of said non-magnetic element contained most in said grain boundaries besides oxygen over the entire recording layer is 1 at % or greater and 4.5 at % or less, and
• a ratio Hn/Hc of a nucleation field for magnetic reversal Hn to coercivity Hc of said recording layer is 0 or greater and 0.5 or less.