Soft magnetic thin film, manufacturing method therefor, perpendicular magnetic recording medium, and magnetic record reproducing device

Abstract

A soft magnetic thin film in which the recording magnetic field in the perpendicular direction can be preferentially intensified and sharply controlled when the thin film is applied to a perpendicular magnetic recording medium is provided. This soft magnetic thin film can be obtained by immersing a substrate into an electroless plating bath that contains a Co ion, Fe ion, and Ni ion as metal ions, as well as a complexing agent and a boron-type reducing agent, wherein the content ratios of the metal ions on the mole basis are 0.15≦(Ni ion amount/the amount of total metal ions) ≦0.40, 0.50≦(Co ion amount/the amount of total metal ions) ≦0.80, and 0.05≦(Fe ion amount/the amount of total metal ions) ≦0.15; and carrying out electroless plating in a magnetic field in a range of 5-2,000 Oe given in a direction parallel to the surface of said substrate.

Dependencies are inferred from the claim text.