Supperresolution readout thin film and information recording medium

An information recording medium comprising a superresolution readout thin film provided on a substrate, said superresolution readout thin film comprising

• at least a phase change component and a high melting point component having a higher melting point than the phase change component, wherein a mean composition thereof is given by:
• L.sub.j H.sub.k,
• where L is a low melting point component comprising at least one element and H is a high melting point component comprising at least one element, the high melting point component having a higher melting point than the phase change component, and j and k are amounts of L and H, respectively, and wherein
• a composition satisfying 20.ltoreq.k/(j+k).ltoreq.40% is a basic composition, and amounts of each element of L and each element of H are within .+-.10 atm % of a value determined by the basic composition and said superresolution readout thin film contains precipitates having a relatively higher melting point than the remaining component, said precipitates including at least one element of H;
• L is a mixture of GeSb.sub.2 Te.sub.4 and at least one selected from the group consisting of Sn, Pb, Sb, Te, Zn, Cd, Se, In, Ga, S, Tl, Mg, Tl.sub.2 Se, TlSe, Tl.sub.2 Se.sub.3, Tl.sub.3 Te.sub.2, TlTe, InBi, In.sub.2 Bi, TeBi, Tl--Se, Tl--Te, PB--Sn, Bi--Sn, Se--Te, S--Se, Bi--Ga, Sn--Zn, Ga--Sn, Ga--In, In.sub.3 SeTe.sub.2, AgInTe.sub.2, GeSb.sub.4 Te.sub.7, Ge.sub.2 Sb.sub.2 Te.sub.5, GeBi.sub.4 Te.sub.7, GeBi.sub.2 Te.sub.4, Ge.sub.3 Bi.sub.2 Te.sub.6, Sn.sub.2 Sb.sub.6 Se.sub.11, Sn.sub.2 Sb.sub.2 Se.sub.5, SnSb.sub.2 Te.sub.4, Pb.sub.2 Sb.sub.6 Te.sub.11, CuAsSe.sub.2, Cu.sub.3 AsSe.sub.3, CuSbS.sub.2, CuSbSe.sub.2, InSe, Sb.sub.2 Se.sub.3, Sb.sub.2 Te.sub.3, Bi.sub.2 Te.sub.3, SnSb, FeTe, Fe.sub.2 Te.sub.3, FeTe.sub.2, ZnSb, Zn.sub.3 Sb.sub.2, VTe.sub.2, V.sub.5 Te.sub.8, AgIn.sub.2, BiSe, InSb, In.sub.2 Te, In.sub.2 Te.sub.5, Ba.sub.4 Tl, Cd.sub.11 Nd, Ba.sub.13 Tl, Cd.sub.6 Nd, and Ba.sub.2 Tl, and
• H is at least one selected from the group consisting of:
• BaPd.sub.2, BaPd.sub.5, NdPd, NdPd.sub.3, NdPd.sub.5, Nd.sub.7 Pt.sub.3, Nd.sub.3 Pt.sub.2, NdPt, Nd.sub.3 Pt.sub.4, NdPt.sub.2, NdPt.sub.5, Bi.sub.2 Nd, BiNd, Bi.sub.3 Nd.sub.4, Bi.sub.3 Nd.sub.5, BiNd.sub.2, Cd.sub.2 Nd, CdNd, Mn.sub.2 Nd, Mn.sub.23 Nd.sub.6, Mn.sub.12 Nd, Nd.sub.5 Sb.sub.3, Nd.sub.4 Sb.sub.3, NdSb, NdSb.sub.2, Fe.sub.2 Nd, Fe.sub.17 Nd.sub.2, Cs.sub.3 Ge.sub.2, CsGe, CsGe.sub.4, Nd.sub.5 Si.sub.3, Nd.sub.5 Si.sub.4, NdSi, Nd.sub.3 Si.sub.4, Nd.sub.2 Si.sub.3, Nd.sub.5 Si.sub.9, Cs.sub.2 Te, NdTe.sub.3, Nd.sub.2 Te.sub.5, NdTe.sub.2, Nd.sub.4 Te.sub.7, Nd.sub.2 Te.sub.3, Nd.sub.3, Te.sub.4, NdTe, Ce.sub.3 Ir, Ce.sub.2 Ir, Ce.sub.55 Ir.sub.45, CeIr.sub.2, CeIr.sub.3, Ce.sub.2 Ir.sub.7, CeIr.sub.5, CaPd, CaPd.sub.2, CaGe, Ca.sub.2 Ge, GeNa.sub.3, GeNa, CaSi.sub.2, Ca.sub.2 Si, CaSi, Se.sub.2 Sr, Se.sub.3 Sr.sub.2, SeSr, GeSr.sub.2, GeSr, Ge.sub.2 Sr, SnSr, Sn.sub.3 Sr.sub.5, SnSr.sub.2, Ce.sub.2 Tl, Ce.sub.5 Tl.sub.3, CeTl.sub.3, Ce.sub.3 Tl.sub.5, CeTl, BaTl, Pd.sub.13 Tl.sub.9, Pd.sub.2 Tl, Pd.sub.3 Tl, Mg.sub.2 Si, Mg.sub.2 Ge, BaPd.sub.2, BaPd.sub.5, Ce.sub.4 Se.sub.7, Ce.sub.3 Se.sub.4, Ce.sub.2 Se.sub.3, CeSe, Ce.sub.5 Se.sub.3, Ce.sub.4 Ge.sub.3, Ce.sub.5 Ge.sub.4, CeGe, Ce.sub.3 Ge.sub.5, Ce.sub.5 Si.sub.3, Ce.sub.3 Si.sub.2, Ce.sub.5 Si.sub.4, CeSi, Ce.sub.3 Si.sub.5, CeSi.sub.2, CeTe.sub.3, Ce.sub.2 Te.sub.5, CeTe.sub.2, Ce.sub.4 Te.sub.7, Ce.sub.3 Te.sub.4, CeTe, La.sub.3 Se.sub.7, LaSe.sub.2, La.sub.4 Se.sub.7, La.sub.2 Se.sub.3, La.sub.3 Se.sub.4, LaSe, GeLa.sub.3, Ge.sub.3 La.sub.5, Ge.sub.3 La.sub.4, Ge.sub.4 La.sub.5, GeLa, Ge.sub.5 La.sub.3, BaSe.sub.2, Ba.sub.2 Se.sub.3, BaSe, PdSe, Mo.sub.3 Se.sub.4, MoSe.sub.2, Ba.sub.2 Ge, BaGe.sub.2, BaGe, Ba.sub.2 Te.sub.3, BaTe, Ge.sub.2 Pd.sub.5, GePd.sub.2, Ge.sub.9, Pd.sub.25, GePd, Ge.sub.3 Pt, Ge.sub.3 Pt, Ge.sub.3 Pt.sub.2, GePt, Ge.sub.2 Pt.sub.3, GePt.sub.2, GePt.sub.3, Pu.sub.3 Sn, Pu.sub.5 Sn.sub.3, Pu.sub.5 Sn.sub.4, Pu.sub.8 Sn.sub.7, Pu.sub.7 Sn.sub.8, PuSn.sub.2, PuSn.sub.3, Pt.sub.5 Te.sub.4, Pt.sub.4 Te.sub.5, PtTe.sub.2, GeNi, Ge.sub.3 Ni.sub.5, Ge.sub.2 Ni.sub.5, GeNi.sub.3, NiTe.sub.0.85, NiTe.sub.0.775, Cr.sub.11 Ge.sub.19, CrGe, Cr.sub.11 Ge.sub.8, Cr.sub.5 Ge.sub.3, Cr.sub.3 Ge, CrSi.sub.2, Cr.sub.5 Si.sub.3, Cr.sub.3 Si, Cr.sub.5 Te.sub.8, Cr.sub.4 Te.sub.5, Cr.sub.3 Te.sub.4, Ge.sub.3 Mn.sub.5, GeMn.sub.2, Mn.sub.6 Si, Mn.sub.9 Si.sub.2, Mn.sub.3 Si, Mn.sub.5 Si.sub.2, Mn.sub.5 Si.sub.3, MnSi, Mn.sub.11 Si.sub.19, Mn.sub.2 Sn, Mn.sub.3.25 Sn, MnTe, Te.sub.2 W, FeGe.sub.2, Fe.sub.5 Ge.sub.3, Fe.sub.3 Ge, Fe.sub.2 Si, Fe.sub.5 Si.sub.3, FeSi, FeSi.sub.2, Ge.sub.2 Mo, Ge.sub.41 Mo.sub.23, Ge.sub.16 Mo.sub.9, Ge.sub.23 Mo.sub.13, Ge.sub.3 Mo.sub.5, GeMo.sub.3, Mo.sub.3 Si, Mo.sub.5 Si.sub.3, MoSi.sub.2, MoSn, MoSn.sub.2, Mo.sub.3 Te.sub.4, MoTe.sub.2, Si.sub.2 Ti, SiTi, Si.sub.4, Ti.sub.5, Si.sub.3 Ti.sub.5, SiTi.sub.3, Sn.sub.5 Ti.sub.6, Sn.sub.3 Ti.sub.5, SnTi.sub.2, SnTi.sub.3, CoGe.sub.2, Co.sub.5 Ge.sub.7, CoGe, Co.sub.5 Ge.sub.3, Co.sub.4 Ge, Co.sub.3 Te.sub.4, Ge.sub.7 Re.sub.3, Re.sub.5 Si.sub.3, ReSi, ReSi.sub.2, and Re.sub.2 Te.

A superresolution readout apparatus comprising

• an information recording medium, said recording medium comprising a superresolution readout thin film provided on a substrate;
• and
• an optical head for irradiating a laser beam to the information recording medium and detecting a reflected light;
• wherein
• said superresolution readout thin film comprises:
• at least a phase change component and a high melting point component having a higher melting point than the phase change component, wherein a mean composition thereof is given by:
• L.sub.j H.sub.k,
• where L is a low melting point component comprising at least one element and H is a high melting point component comprising at least one element, the high melting point component having a higher melting point than the phase change component, and j and k are amounts of L and H, respectively, and wherein
• a composition satisfying 20.ltoreq.k/(j+k).ltoreq.40% is a basic composition, and amounts of each element of L and each element of H are within .+-.10 atm % of a value determined by the basic composition and said superresolution readout thin film contains precipitates having a relatively higher melting point than the remaining component, said precipitates including at least one element of H;
• L is a mixture of GeSb.sub.2 Te.sub.4 and at least one selected from the group consisting of Sn, Pb, Sb, Te, Zn, Cd, Se, In, Ga, S, Tl, Mg, Tl.sub.2 Se, TlSe, Tl.sub.2 Se.sub.3, Tl.sub.3 Te.sub.2, TlTe, InBi, In.sub.2 Bi, TeBi, Tl--Se, Tl--Te, PB--Sn, Bi--Sn, Se--Te, S--Se, Bi--Ga, Sn--Zn, Ga--Sn, Ga--In, In.sub.3 SeTe.sub.2, AgInTe.sub.2, GeSb.sub.4 Te.sub.7, Ge.sub.2 Sb.sub.2 Te.sub.5, GeBi.sub.4 Te.sub.7, GeBi.sub.2 Te.sub.4, Ge.sub.3 Bi.sub.2 Te.sub.6, Sn.sub.2 Sb.sub.6 Se.sub.11, Sn.sub.2 Sb.sub.2 Se.sub.5, SnSb.sub.2 Te.sub.4, Pb.sub.2 Sb.sub.6 Te.sub.11, CuAsSe.sub.2, Cu.sub.3 AsSe.sub.3, CuSbS.sub.2, CuSbSe.sub.2, InSe, Sb.sub.2 Se.sub.3, Sb.sub.2 Te.sub.3, Bi.sub.2 Te.sub.3, SnSb, FeTe, Fe.sub.2 Te.sub.3, FeTe.sub.2, ZnSb, Zn.sub.3 Sb.sub.2, VTe.sub.2, V.sub.5 Te.sub.8, AgIn.sub.2, BiSe, InSb, In.sub.2 Te, In.sub.2 Te.sub.5, Ba.sub.4 Tl, Cd.sub.11 Nd, Ba.sub.13 Tl, Cd.sub.6 Nd, and Ba.sub.2 Tl, and
• H is at least one selected from the group consisting of:
• BaPd.sub.2, BaPd.sub.5, NdPd, NdPd.sub.3, NdPd.sub.5, Nd.sub.7 Pt.sub.3, Nd.sub.3 Pt.sub.2, NdPt, Nd.sub.3 Pt.sub.4, NdPt.sub.2, NdPt.sub.5, Bi.sub.2 Nd, BiNd, Bi.sub.3 Nd.sub.4, Bi.sub.3 Nd.sub.5, BiNd.sub.2, Cd.sub.2 Nd, CdNd, Mn.sub.2 Nd, Mn.sub.23 Nd.sub.6, Mn.sub.12 Nd, Nd.sub.5 Sb.sub.3, Nd.sub.4 Sb.sub.3, NdSb, NdSb.sub.2, Fe.sub.2 Nd, Fe.sub.17 Nd.sub.2, Cs.sub.3 Ge.sub.2, CsGe, CsGe.sub.4, Nd.sub.5 Si.sub.3, Nd.sub.5 Si.sub.4, NdSi, Nd.sub.3 Si.sub.4, Nd.sub.2 Si.sub.3, Nd.sub.5 Si.sub.9, Cs.sub.2 Te, NdTe.sub.3, Nd.sub.2 Te.sub.5, NdTe.sub.2, Nd.sub.4 Te.sub.7, Nd.sub.2 Te.sub.3, Nd.sub.3, Te.sub.4, NdTe, Ce.sub.3 Ir, Ce.sub.2 Ir, Ce.sub.55 Ir.sub.45, CeIr.sub.2, CeIr.sub.3, Ce.sub.2 Ir.sub.7, CeIr.sub.5, CaPd, CaPd.sub.2, CaGe, Ca.sub.2 Ge, GeNa.sub.3, GeNa, CaSi.sub.2, Ca.sub.2 Si, CaSi, Se.sub.2 Sr, Se.sub.3 Sr.sub.2, SeSr, GeSr.sub.2, GeSr, Ge.sub.2 Sr, SnSr, Sn.sub.3 Sr.sub.5, SnSr.sub.2, Ce.sub.2 Tl, Ce.sub.5 Tl.sub.3, CeTl.sub.3, Ce.sub.3 Tl.sub.5, CeTl, BaTl, Pd.sub.13 Tl.sub.9, Pd.sub.2 Tl, Pd.sub.3 Tl, Mg.sub.2 Si, Mg.sub.2 Ge, BaPd.sub.2, BaPd.sub.5, Ce.sub.4 Se.sub.7, Ce.sub.3 Se.sub.4, Ce.sub.2 Se.sub.3, CeSe, Ce.sub.5 Se.sub.3, Ce.sub.4 Ge.sub.3, Ce.sub.5 Ge.sub.4, CeGe, Ce.sub.3 Ge.sub.5, Ce.sub.5 Si.sub.3, Ce.sub.3 Si.sub.2, Ce.sub.5 Si.sub.4, CeSi, Ce.sub.3 Si.sub.5, CeSi.sub.2, CeTe.sub.3, Ce.sub.2 Te.sub.5, CeTe.sub.2, Ce.sub.4 Te.sub.7, Ce.sub.3 Te.sub.4, CeTe, La.sub.3 Se.sub.7, LaSe.sub.2, La.sub.4 Se.sub.7, La.sub.2 Se.sub.3, La.sub.3 Se.sub.4, LaSe, GeLa.sub.3, Ge.sub.3 La.sub.5, Ge.sub.3 La.sub.4, Ge.sub.4 La.sub.5, GeLa, Ge.sub.5 La.sub.3, BaSe.sub.2, Ba.sub.2 Se.sub.3, BaSe, PdSe, Mo.sub.3 Se.sub.4, MoSe.sub.2, Ba.sub.2 Ge, BaGe.sub.2, BaGe, Ba.sub.2 Te.sub.3, BaTe, Ge.sub.2 Pd.sub.5, GePd.sub.2, Ge.sub.9, Pd.sub.25, GePd, Ge.sub.3 Pt, Ge.sub.3 Pt, Ge.sub.3 Pt.sub.2, GePt, Ge.sub.2 Pt.sub.3, GePt.sub.2, GePt.sub.3, Pu.sub.3 Sn, Pu.sub.5 Sn.sub.3, Pu.sub.5 Sn.sub.4, Pu.sub.8 Sn.sub.7, Pu.sub.7 Sn.sub.8, PuSn.sub.2, PuSn.sub.3, Pt.sub.5 Te.sub.4, Pt.sub.4 Te.sub.5, PtTe.sub.2, GeNi, Ge.sub.3 Ni.sub.5, Ge.sub.2 Ni.sub.5, GeNi.sub.3, NiTe.sub.0.85, NiTe.sub.0.775, Cr.sub.11 Ge.sub.19, CrGe, Cr.sub.11 Ge.sub.8, Cr.sub.5 Ge.sub.3, Cr.sub.3 Ge, CrSi.sub.2, Cr.sub.5 Si.sub.3, Cr.sub.3 Si, Cr.sub.5 Te.sub.8, Cr.sub.4 Te.sub.5, Cr.sub.3 Te.sub.4, Ge.sub.3 Mn.sub.5, GeMn.sub.2, Mn.sub.6 Si, Mn.sub.9 Si.sub.2, Mn.sub.3 Si, Mn.sub.5 Si.sub.2, Mn.sub.5 Si.sub.3, MnSi, Mn.sub.11 Si.sub.19, Mn.sub.2 Sn, Mn.sub.3.25 Sn, MnTe, Te.sub.2 W, FeGe.sub.2, Fe.sub.5 Ge.sub.3, Fe.sub.3 Ge, Fe.sub.2 Si, Fe.sub.5 Si.sub.3, FeSi, FeSi.sub.2, Ge.sub.2 Mo, Ge.sub.41 Mo.sub.23, Ge.sub.16 Mo.sub.9, Ge.sub.23 Mo.sub.13, Ge.sub.3 Mo.sub.5, GeMo.sub.3, Mo.sub.3 Si, Mo.sub.5 Si.sub.3, MoSi.sub.2, MoSn, MoSn.sub.2, Mo.sub.3 Te.sub.4, MoTe.sub.2, Si.sub.2 Ti, SiTi, Si.sub.4, Ti.sub.5, Si.sub.3 Ti.sub.5, SiTi.sub.3, Sn.sub.5 Ti.sub.6, Sn.sub.3 Ti.sub.5, SnTi.sub.2, SnTi.sub.3, CoGe.sub.2, Co.sub.5 Ge.sub.7, CoGe, Co.sub.5 Ge.sub.3, Co.sub.4 Ge, Co.sub.3 Te.sub.4, Ge.sub.7 Re.sub.3, Re.sub.5 Si.sub.3, ReSi, ReSi.sub.2, and Re.sub.2 Te.