REWRITABLE OPTICAL DATA STORAGE MEDIUM AND USE OF SUCH A MEDIUM

摘要

A rewritable optical data storage medium ( 20 ) for high-speed recording by means of a focused radiation beam ( 10 ) is described. The medium ( 20 ) comprises a substrate ( 1 ) carrying a stack ( 2 ) of layers, which stack ( 2 ) comprises, a first auxiliary layer ( 3 ), a second auxiliary layer ( 5 ), and a recording layer ( 4 ) of a phase-change material mainly comprising an alloy of Sb and at least one of Ga and In. The recording layer ( 4 ) is interposed between the first auxiliary layer ( 3 ) and the second auxiliary layer ( 5 ). If the alloy is of a composition in atomic percentages defined by the formula: Ga_xIn_ySb_z and 70=z=95 and x+y+z=100 the recording layer ( 4 ) has a crystallization speed making it suitable for direct overwrite high speed recording at a velocity of more than 10 m/s and an archival life stability of at least 10 years at 30° C. Further the recording layer ( 4 ) has a relatively low media noise.