Magnetic recording medium having a metal underlayer and a CoCr alloy magnetic thin film

摘要

Disclosed is magnetic recording media having a high coercivity sufficient to cope with the recent high density recording, low noise property and excellent squareness, and a target for forming a magnetic film useful for realizing the magnetic recording media. The magnetic film is made of a Co based alloy containing: Cr in an amount of 8-18 atomic %; one kind or more of elements selected from a group consisting of V, Mo and W in an amount of 3-10 atomic %, or one kind or more of the elements and Ta in an amount of 3-10 atomic %; Pt in an amount of 0.5 to 20 atomic % or Ni in an amount of 5-30 atomic %, as needed; and the balance being Co and inevitable impurities, wherein the total content of Cr and one kind or more of the elements selected from a group consisting of V, Mo and W, or of Cr and one kind or more of the elements and Ta is specified to be 24 atomic % or less. A target for forming the magnetic film is formed by melting, casting and hot-rolling the Co alloy having the above composition, and it has a maximum permeability of 100 or less.