Patent ID: 8012559

Claim:
An optical information recording medium including a transparent substrate, a recording layer can change in phase reversibly by irradiation of a laser beam, a first protective layer (excluding one containing a Mg compound), a second protective layer (excluding one containing a Mg compound) and a reflective layer in which the first protective layer, the recording layer, the second protective layer and the reflective layer are provided in this order from a side nearer to a plane of incidence of the laser beam, wherein; either or both of a first interface layer and a second interface layer, the first interface being disposed between the first protective layer and the recording layer and the second interface layer being disposed between the second protective layer and the recording layer; the recording layer comprises a Ge—Sb—Bi—Te-based material consisting of Ge, Sb, Bi and Te; the Ge—Sb—Bi—Te-based material consists of a GeTe compound, a Sb 2 Te 3 compound and a Bi 2 Te 3 compound and has a composition which is obtained by adding Sb or Bi, or both of Sb and Bi to a material in which a molar ratio of the Gete compound to the (Sb—Bi) 2 Te 3 (a value of GeTe compound/(Sb—Bi) 2 Te 3 ) is 4 to 12; the composition of the Ge—Sb—Bi—Te-based material is within a region which is bounded by composition points A(Ge 41.2 , (Sb—Bi) 7.4 , Te 51.4 ), B(Ge 39.8 , (Sb—Bi) 10.5 , Te 49.7 ), C(Ge 28.5 , (Sb—Bi) 21.7 , Te 49.8 ), and D(Ge 30.6 , (Sb—Bi) 15.8 , Te 53.6 ) in a triangular coordinate graph whose apices are Ge, Sb—Bi and Te, and a content of Bi contained in the Ge—Sb—Bi—Te-based material is 4 atom % and more and less than 13 atom %; and the interface layer (excluding one containing a hafnium oxide, one containing a cerium oxide, one containing a carbide and one containing carbon) comprises a Zr oxide.