| 摘要 |
PROBLEM TO BE SOLVED: To provide a glass substrate not causing a trouble in recording and reproducing of a magnetic disk even at a floating condition of a recording element or a reproducing element with a floating distance of 2 mm or less.SOLUTION: The glass substrate for the magnetic disk contains an alkali metal component as a glass component, and its end face is a mirror surface. A load factor curve of a roughness cross sectional area is obtained by measurement of the surface roughness of the end face after being etched by 2.5 μm, and a roughness percentage is 40% or more when the load factor of the roughness cross sectional area is 50%.SELECTED DRAWING: Figure 3 |
