Glass for magnetic recording medium substrate or for glass spacer to be used in magnetic recording/reproducing device, magnetic recording medium substrate, magnetic recording medium, glass spacer to be used in magnetic recording/reproducing device, and magnetic recording/reproducing device

A glass for a magnetic recording medium substrate or for a glass spacer for a magnetic recording/reproducing device, the glass being an amorphous glass,

• wherein a Li2O content is 2.5 mol % or more and 6.0 mol % or less,
• a total content of Na2O and K2O is 0 mol %,
• a B2O3 content is 0 mol % or more and 1.0 mol % or less,
• a CaO content is 0 mol % or more and 0.1 mol % or less,
• a MgO content is 19.2 mol % or more and 23.0 mol % or less,
• a TiO2 content is 0 mol %,
• a SiO2 content is more than 56.0 mol % and 65.0 mol % or less,
• an Al2O3 content is more than 13.0 mol % and 15.0 mol % or less,
• a Y2O3 content is 0 mol %,
• an average linear expansion coefficient within a temperature range of 100° C. to 300° C. of the glass is 38.4×10−7/° C. or more and 52.5×10−7/° C. or less,
• a glass transition temperature Tg of the glass is 697° C. or more and 745° C. or less,
• a Young's modulus of the glass is 95.9 GPa or more and 100.1 GPa or less, and
• a specific elastic modulus of the glass is 38.2 MNm/kg or more and 38.8 MNm/kg or less.