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Abstract

There is provided a glass-ceramic substrate for a magnetic information storage medium having a data zone and a landing zone capable of stably lifting a magnetic head in the landing zone and also capable of reducing the amount of lifting of the magnetic head in the data zone for realizing a high recording density. The landing zone has a multiplicity of projections or depressions formed by irradiation of laser beam. A CO.sub.2 laser or a laser diode pumped solid-state laser can be used for this purpose. The surface roughness (Ra) of a polished surface of the landing zone is within a range from 3 .ANG. to 9 .ANG., height of the projections or depressions is within a range from 50 .ANG. to 300 .ANG., surface roughness (Ra) of the projections or depressions is within a range from 10 .ANG. to 50 .ANG. and interval of the projections or depressions is within a range from 10 .mu.m to 200 .mu.m. A preferable glass-ceramic used is a glass-ceramic of a SiO.sub.2 --Li.sub.2 O--K.sub.2 O--MgO--ZnO--P.sub.2 O.sub.5 --Al.sub.2 O.sub.3 system or a SiO.sub.2 --Li.sub.2 O--K.sub.2 O--MgO--ZnO--P.sub.2 O.sub.5 --Al.sub.2 O.sub.3 --ZrO.sub.2 system. For stable forming of projections or depressions in the landing zone by a laser diode pumped solid-state laser, the glass-ceramic preferably includes at least two coloring agents selected from NiO, CoO, MnO.sub.2, V.sub.2 O.sub.5, CuO and Cr.sub.2 O.sub.3.

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