摘要 |
A glass for a magnetic recording medium substrate, which contains SiO2, Li2O, Na2O, and MgO as essential components; alkali metal oxides selected from the group consisting of Li2O, Na2O, and K2O of 6 to 15 mol % in total; alkaline earth metal oxides selected from the group consisting of MgO, CaO, SrO, and BaO of 10 to 30 mol % in total. A molar ratio of a content of Li2O to a total content of alkali metal oxides {Li2O/(Li2O+Na2O+K2O)} is greater than 0 and less than or equal to 0.3; a molar ratio of a content of MgO to a total content of alkaline earth metal oxides {MgO/(MgO+CaO+SrO+BaO)} is greater than or equal to 0.80; a glass transition temperature is greater than or equal to 650° C.; and a Young's modulus is greater than or equal to 80 GPa. |