SUBSTRATE FOR VERTICAL MAGNETIC RECORDING MEDIUM, VERTICAL MAGNETIC RECORDING MEDIUM AND METHOD FOR MANUFACTURING THESE

摘要

PROBLEM TO BE SOLVED: To provide a substrate for a vertical magnetic recording medium which excels in mass productivity, functions as a soft magnetic backing layer of the vertical magnetic recording medium as well and of which the surface hardness is assured. SOLUTION: An Al-Mg alloy or materials similar thereto are used as a nonmagnetic substrate 1 in a disk substrate for the vertical magnetic recording medium. A soft magnetic underlayer 3 composed of an Ni-P alloy containing 0.5 to 6wt% P formed by an electroless plating method is formed on the nonmagnetic substrate 1. The film thickness of the soft magnetic underlayer 3 is≥3μm in order to assure the hardness of the substrate surface. The disk substrate for the vertical magnetic recording medium functions as the soft magnetic backing layer even in the state not being subjected to heat treatment. COPYRIGHT: (C)2005,JPO&NCIPI