Patent ID: 7090937

Claim:
A magnetic information recording medium, comprising a magnetic recording layer formed on a glass substrate made of a non-crystallized glass containing SiO 2 , B 2 O 3 and Al 2 O 3 as essential components, comprising, by mol %, 40 to 75% of SiO 2 , 1 to 25% of B 2 O 3 , 1 to 20% Al 2 O 3 and 5 to 15% of Li 2 O, 2 to 45% of a total of B 2 O 3 and Al 2 O 3 and 0 to 40% of R′ 2 O in which R′ is at least one member selected from the group consisting of Li, Na and K, wherein the total content of SiO 2 , B 2 O 3 , Al 2 O 3 and R′ 2 O is at least 90 mol %, the glass having a specific modulus of 30×10 6 N·m/kg or higher and the glass substrate having no chemical strengthened layer.