| 摘要 |
Proposed are a substrate that comprises an easily producible soft magnetic backing film and can reduce spike noise from the soft magnetic backing film, and a method for producing the substrate. More specifically, provided are a substrate for a perpendicular magnetic recording hard disk medium, comprising an Si single crystal substrate (1) having a diameter of 65 mm or less, a thickness of 1 mm or less and an average surface roughness (Rms) of 1 nm or more and 1000 nm or less; an under-plated layer (2) formed on the substrate, the layer (2) comprising one or more metals selected from a group consisting of Ni, Cu and Ag and having a thickness of 1 nm to 300 nm; and a plated soft magnetic layer (3) formed on the under-plated layer, the layer (3) having a thickness of 50 nm or more and less than 1000 nm, a coercivity of 20 Oe(oersteds) or less and a saturation magnetization of 1T or more, wherein the average surface roughness (Rms) of the plated soft magnetic layer is 0.1 nm or more and 5 nm or less.
|
