| 摘要 |
PURPOSE:To obtain an information recording medium enabling recording and erasure by adding prescribed percentages of Al and a rare earth element to Cu and allowing the resulting alloy to form phases having different crystal structures in two temp. ranges so as to change reversibly the spectral reflectance. CONSTITUTION:An alloy having variable spectral reflectance is composed of 13-22wt% Al, <=15wt% in total of one or more kinds of elements selected among the elements belonging to the groups IA, IIA, IVA, VA, VIA, VIIA and VIII in the periodic table, the rare earth elements, etc., and the balance Cu. The alloy has different crystal structures at the 1st temp. above room temp. and a temp. below the 1st temp. in a solid state. When the alloy is rapidly cooled from the higher temp., the crystal structure changes to a structure different from a crystal structure formed by nonrapid cooling at the lower temp. Thus, two or more kinds of spectral reflectances are obtd. by heating and cooling in a solid state. |
