<p>A magneto-optic memory medium of an amorphous alloy having uniaxial magnetic anisotropy and prepared by incorporating 2 to 15 atom mol % of yttrium Y into an alloy represented by the formula (Gd alpha Tb1- alpha )1- beta A beta wherein A is a transition metal, and alpha and beta satisfy the requirements of 0.5 </= alpha </= 0.7 and 0.6 < beta </= 0.8.</p>
