Patent ID: 7449225

Claim:
An information recording medium including a substrate and an information layer arranged on the substrate, the information layer comprising: a recording layer that is changed in phase reversibly between a crystalline phase and an amorphous phase by at least one of optical means and electrical means; and at least one crystalline nucleation layer that contains at least one element selected from Bi and Te and at least one element (M1) selected from Sc, Y, Nd, Sm, Gd, Tb, Dy, Ho, Er, Yb, and Lu, and is provided in contact with the recording layer, wherein the recording layer contains at least one element (M2) selected from Sb and Bi, Ge, and Te, and where the element M2, Ge, and Te are represented by a composition formula Ge a (M2) b Te 3+a , 2≦a≦50 and 2≦b≦4 are satisfied.