Supperresolution readout thin film and information recording medium

Claim 2

A superresolution readout thin film formed directly on a substrate or through a protective layer to provide a superresolution effect by irradiation of a readout beam, 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≦k/(j+k)≦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 2 Te 4 and at least one selected from the group consisting of Sn, Pb, Sb, Te, Zn, Cd, Se, In, Ga, S, Tl, Mg, Tl 2 Se, TlSe, Tl 2 Se 3 , Tl 3 Te 2 , TlTe, InBi, In 2 Bi, TeBi, Tl--Se, Tl--Te, PB--Sn, Bi--Sn, Se--Te, S--Se, Bi--Ga, Sn--Zn, Ga--Sn, Ga--In, In 3 SeTe 2 , AgInTe 2 , GeSb 4 Te 7 , Ge 2 Sb 2 Te 5 , GeBi 4 Te 7 , GeBi 2 Te 4 , Ge 3 Bi 2 Te 6 , Sn 2 Sb 6 Se 11 , Sn 2 Sb 2 Se 5 , SnSb 2 Te 4 , Pb 2 Sb 6 Te 11 , CuAsSe 2 , Cu 3 AsSe 3 , CuSbS 2 , CuSbSe 2 , InSe, Sb 2 Se 3 , Sb 2 Te 3 , Bi 2 Te 3 , SnSb, FeTe, Fe 2 Te 3 , FeTe 2 , ZnSb, Zn 3 Sb 2 , VTe 2 , V 5 Te 8 , AgIn 2 , BiSe, InSb, In 2 Te, In 2 Te 5 , Ba 4 Tl, Cd 11 Nd, Ba 13 Tl, Cd 6 Nd, and Ba 2 Tl, and H is at least one selected from the group consisting of: BaPd 2 , BaPd 5 , NdPd, NdPd 3 , NdPd 5 , Nd 7 Pt 3 , Nd 3 Pt 2 , NdPt, Nd 3 Pt 4 , NdPt 2 , NdPt 5 , Bi 2 Nd, BiNd, Bi 3 Nd 4 , Bi 3 Nd 5 , BiNd 2 , Cd 2 Nd, CdNd, Mn 2 Nd, Mn 23 Nd 6 , Mn 12 Nd, Ndhd 5b 3 , Nd 4 Sb 3 , NdSb, NdSb 2 , Fe 2 Nd, Fe 17 Nd 2 , Cs 3 Ge 2 , CsGe, CsGe 4 , Nd 5 Si 3 , Nd 5 Si 4 , NdSi, Nd 3 Si 4 , Nd 2 Si 3 , Nd 5 Si 9 , Cs 2 Te, NdTe 3 , Nd 2 Te 5 , NdTe 2 , Nd 4 Te 7 , Nd 2 Te 3 , Nd 3 , Te 4 , NdTe, Ce 3 Ir, Ce 2 Ir, Ce 55 Ir 45 , CeIr 2 , CeIr 3 , Ce 2 Ir 7 , CeIr 5 , CaPd, CaPd 2 , CaGe, Ca 2 Ge, GeNa 3 , GeNa, CaSi 2 , Ca 2 Si, CaSi, Se 2 Sr, Se 3 Sr 2 , SeSr, GeSr 2 , GeSr, Ge 2 Sr, SnSr, Sn 3 Sr 5 , SnSr 2 , Ce 2 Tl, Ce 5 Tl 3 , CeTl 3 , Ce 3 Tl 5 , CeTl, BaTl, Pd 13 Tl 9 , Pd 2 Tl, Pd 3 Tl, Mg 2 Si, Mg 2 Ge, BaPd 2 , BaPd 5 , Ce 4 Se 7 , Ce 3 Se 4 , Ce 2 Se 3 , CeSe, Ce 5 Se 3 , Ce 4 Ge 3 , Ce 5 Ge 4 , CeGe, Ce 3 Ge 5 , Ce 5 Si 3 , Ce 3 Si 2 , Ce 5 Si 4 , CeSi, Ce 3 Si 5 , CeSi 2 , CeTe 3 , Ce 2 Te 5 , CeTe 2 , Ce 4 Te 7 , Ce 3 Te 4 , CeTe, La 3 Se 7 , LaSe 2 , La 4 Se 7 , La 2 Se 3 , La 3 Se 4 , LaSe, GeLa 3 , Ge 3 La 5 , Ge 3 La 4 , Ge 4 La 5 , GeLa, Ge 5 La 3 , BaSe 2 , Ba 2 Se 3 , BaSe, PdSe, Mo 3 Se 4 , MoSe 2 , Ba 2 Ge, BaGe 2 , BaGe, Ba 2 Te 3 , BaTe, Ge 2 Pd 5 , GePd 2 , Ge 9 , Pd 25 , GePd, Ge 3 Pt, Ge 3 Pt, Ge 3 Pt 2 , GePt, Ge 2 Pt 3 , GePt 2 , GePt 3 , Pu 3 Sn, Pu 5 Sn 3 , Pu 5 Sn 4 , Pu 8 Sn 7 , Pu 7 Sn 8 , PuSn 2 , PuSn 3 , Pt 5 Te 4 , Pt 4 Te 5 , PtTe 2 , GeNi, Ge 3 Ni 5 , Ge 2 Ni 5 , GeNi 3 , NiTe 0 .85, NiTe 0 .775, Cr 11 Ge 19 , CrGe, Cr 11 Ge 8 , Cr 5 Ge 3 , Cr 3 Ge, CrSi 2 , Cr 5 Si 3 , Cr 3 Si, Cr 5 Te 8 , Cr 4 Te 5 , Cr 3 Te 4 , Ge 3 Mn 5 , GeMn 2 , Mn 6 Si, Mn 9 Si 2 , Mn 3 Si, Mn 5 Si 2 , Mn 5 Si 3 , MnSi, Mn 11 Si 19 , Mn 2 Sn, Mn 3 .25 Sn, MnTe, Te 2 W, FeGe 2 , Fe 5 Ge 3 , Fe 3 Ge, Fe 2 Si, Fe 5 Si 3 , FeSi, FeSi 2 , Ge 2 Mo, Ge 41 Mo 23 , Ge 16 Mo 9 , Ge 23 Mo 13 , Ge 3 Mo 5 , GeMo 3 , Mo 3 Si, Mo 5 Si 3 , MoSi 2 , MoSn, MoSn 2 , Mo 3 Te 4 , MoTe 2 , Si 2 Ti, SiTi, Si 4 , Ti 5 , Si 3 Ti 5 , SiTi 3 , Sn 5 Ti 6 , Sn 3 Ti 5 , SnTi 2 , SnTi 3 , CoGe 2 , Co 5 Ge 7 , CoGe, Co 5 Ge 3 , Co 4 Ge, Co 3 Te 4 , Ge 7 Re 3 , Re 5 Si 3 , ReSi, ReSi 2 , and Re 2 Te.

Claim 3

The superresolution readout thin film according to claim 1, wherein the melting point of the low melting point component of the thin film is not higher than 650° C.

Claim 4

The superresolution readout thin film according to claim 1, wherein the melting point of the low melting point component of the thin film is not higher than 250° C.

Claim 5

The superresolution readout thin film according to claim 1, wherein at least one of the real part and the imaginary part of the complex refractive index of the thin film is changed by not less than 20% by irradiation of the energy beam as compared with one before the irradiation.

Claim 6

The superresolution readout thin film according to claim 1, wherein sum of numbers of atoms composing the high melting point component is in a range of 10 to 50% of sum of numbers of all atoms composing the thin film.

Claim 7

The superresolution readout thin film according to claim 1, wherein the melting point of the high melting point component is not lower than 780° C.

Claim 8

The superresolution readout thin film according to claim 1, wherein difference of the melting point of the high melting point component from the melting point of the low melting point component of the thin film is not smaller than 150° C.

Claim 9

The superresolution readout thin film according to claim 1, wherein the high melting point component is precipitated in a columnar shape or a granular shape.

Claim 10

The superresolution readout thin film according to claim 1, wherein the high melting point component is precipitated in a porous state.

Claim 11

The superresolution readout thin film according to claim 1, wherein both of the low melting point component and the high melting point component contain a metal element or a semi-metal element by not less than 50 atm %.

Claim 12

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≦k/(j+k)≦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 2 Te 4 and at least one selected from the group consisting of Sn, Pb, Sb, Te, Zn, Cd, Se, In, Ga, S, Tl, Mg, Tl 2 Se, TlSe, Tl 2 Se 3 , Tl 3 Te 2 , TlTe, InBi, In 2 Bi, TeBi, Tl--Se, Tl--Te, PB--Sn, Bi--Sn, Se--Te, S--Se, Bi--Ga, Sn--Zn, Ga--Sn, Ga--In, In 3 SeTe 2 , AgInTe 2 , GeSb 4 Te 7 , Ge 2 Sb 2 Te 5 , GeBi 4 Te 7 , GeBi 2 Te 4 , Ge 3 Bi 2 Te 6 , Sn 2 Sb 6 Se 11 , Sn 2 Sb 2 Se 5 , SnSb 2 Te 4 , Pb 2 Sb 6 Te 11 , CuAsSe 2 , Cu 3 AsSe 3 , CuSbS 2 , CuSbSe 2 , InSe, Sb 2 Se 3 , Sb 2 Te 3 , Bi 2 Te 3 , SnSb, FeTe, Fe 2 Te 3 , FeTe 2 , ZnSb, Zn 3 Sb 2 , VTe 2 , V 5 Te 8 , AgIn 2 , BiSe, InSb, In 2 Te, In 2 Te 5 , Ba 4 Tl, Cd 11 Nd, Ba 13 Tl, Cd 6 Nd, and Ba 2 Tl, and H is at least one selected from the group consisting of: BaPd 2 , BaPd 5 , NdPd, NdPd 3 , NdPd 5 , Nd 7 Pt 3 , Nd 3 Pt 2 , NdPt, Nd 3 Pt 4 , NdPt 2 , NdPt 5 , Bi 2 Nd, BiNd, Bi 3 Nd 4 , Bi 3 Nd 5 , BiNd 2 , Cd 2 Nd, CdNd, Mn 2 Nd, Mn 23 Nd 6 , Mn 12 Nd, Nd 5 Sb 3 , Nd 4 Sb 3 , NdSb, NdSb 2 , Fe 2 Nd, Fe 17 Nd 2 , Cs 3 Ge 2 , CsGe, CsGe 4 , Nd 5 Si 3 , Nd 5 Si 4 , NdSi, Nd 3 Si 4 , Nd 2 Si 3 , Nd 5 Si 9 , Cs 2 Te, NdTe 3 , Nd 2 Te 5 , NdTe 2 , Nd 4 Te 7 , Nd 2 Te 3 , Nd 3 , Te 4 , NdTe, Ce 3 Ir, Ce 2 Ir, Ce 55 Ir 45 , CeIr 2 , CeIr 3 , Ce 2 Ir 7 , CeIr 5 , CaPd, CaPd 2 , CaGe, Ca 2 Ge, GeNa 3 , GeNa, CaSi 2 , Ca 2 Si, CaSi, Se 2 Sr, Se 3 Sr 2 , SeSr, GeSr 2 , GeSr, Ge 2 Sr, SnSr, Sn 3 Sr 5 , SnSr 2 , Ce 2 Tl, Ce 5 Tl 3 , CeTl 3 , Ce 3 Tl 5 , CeTl, BaTl, Pd 13 Tl 9 , Pd 2 Tl, Pd 3 Tl, Mg 2 Si, Mg 2 Ge, BaPd 2 , BaPd 5 , Ce 4 Se 7 , Ce 3 Se 4 , Ce 2 Se 3 , CeSe, Ce 5 Se 3 , Ce 4 Ge 3 , Ce 5 Ge 4 , CeGe, Ce 3 Ge 5 , Ce 5 Si 3 , Ce 3 Si 2 , Ce 5 Si 4 , CeSi, Ce 3 Si 5 , CeSi 2 , CeTe 3 , Ce 2 Te 5 , CeTe 2 , Ce 4 Te 7 , Ce 3 Te 4 , CeTe, La 3 Se 7 , LaSe 2 , La 4 Se 7 , La 2 Se 3 , La 3 Se 4 , LaSe, GeLa 3 , Ge 3 La 5 , Ge 3 La 4 , Ge 4 La 5 , GeLa, Ge 5 La 3 , BaSe 2 , Ba 2 Se 3 , BaSe, PdSe, Mo 3 Se 4 , MoSe 2 , Ba 2 Ge, BaGe 2 , BaGe, Ba 2 Te 3 , BaTe, Ge 2 Pd 5 , GePd 2 , Ge 9 , Pd 25 , GePd, Ge 3 Pt, Ge 3 Pt, Ge 3 Pt 2 , GePt, Ge 2 Pt 3 , GePt 2 , GePt 3 , Pu 3 Sn, Pu 5 Sn 3 , Pu 5 Sn 4 , Pu 8 Sn 7 , Pu 7 Sn 8 , PuSn 2 , PuSn 3 , Pt 5 Te 4 , Pt 4 Te 5 , PtTe 2 , GeNi, Ge 3 Ni 5 , Ge 2 Ni 5 , GeNi 3 , NiTe 0 .85, NiTe 0 .775, Cr 11 Ge 19 , CrGe, Cr 11 Ge 8 , Cr 5 Ge 3 , Cr 3 Ge, CrSi 2 , Cr 5 Si 3 , Cr 3 Si, Cr 5 Te 8 , Cr 4 Te 5 , Cr 3 Te 4 , Ge 3 Mn 5 , GeMn 2 , Mn 6 Si, Mn 9 Si 2 , Mn 3 Si, Mn 5 Si 2 , Mn 5 Si 3 , MnSi, Mn 11 Si 19 , Mn 2 Sn, Mn 3 .25 Sn, MnTe, Te 2 W, FeGe 2 , Fe 5 Ge 3 , Fe 3 Ge, Fe 2 Si, Fe 5 Si 3 , FeSi, FeSi 2 , Ge 2 Mo, Ge 41 Mo 23 , Ge 16 Mo 9 , Ge 23 Mo 13 , Ge 3 Mo 5 , GeMo 3 , Mo 3 Si, Mo 5 Si 3 , MoSi 2 , MoSn, MoSn 2 , Mo 3 Te 4 , MoTe 2 , Si 2 Ti, SiTi, Si 4 , Ti 5 , Si 3 Ti 5 , SiTi 3 , Sn 5 Ti 6 , Sn 3 Ti 5 , SnTi 2 , SnTi 3 , CoGe 2 , Co 5 Ge 7 , CoGe, Co 5 Ge 3 , Co 4 Ge, Co 3 Te 4 , Ge 7 Re 3 , Re 5 Si 3 , ReSi, ReSi 2 , and Re 2 Te.

Claim 13

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≦k/(j+k)≦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 2 Te 4 and at least one selected from the group consisting of Sn, Pb, Sb, Te, Zn, Cd, Se, In, Ga, S, Tl, Mg, Tl 2 Se, TlSe, Tl 2 Se 3 , Tl 3 Te 2 , TlTe, InBi, In 2 Bi, TeBi, Tl--Se, Tl--Te, PB--Sn, Bi--Sn, Se--Te, S--Se, Bi--Ga, Sn--Zn, Ga--Sn, Ga--In, In 3 SeTe 2 , AgInTe 2 , GeSb 4 Te 7 , Ge 2 Sb 2 Te 5 , GeBi 4 Te 7 , GeBi 2 Te 4 , Ge 3 Bi 2 Te 6 , Sn 2 Sb 6 Se 11 , Sn 2 Sb 2 Se 5 , SnSb 2 Te 4 , Pb 2 Sb 6 Te 11 , CuAsSe 2 , Cu 3 AsSe 3 , CuSbS 2 , CuSbSe 2 , InSe, Sb 2 Se 3 , Sb 2 Te 3 , Bi 2 Te 3 , SnSb, FeTe, Fe 2 Te 3 , FeTe 2 , ZnSb, Zn 3 Sb 2 , VTe 2 , V 5 Te 8 , AgIn 2 , BiSe, InSb, In 2 Te, In 2 Te 5 , Ba 4 Tl, Cd 11 Nd, Ba 13 Tl, Cd 6 Nd, and Ba 2 Tl, and H is at least one selected from the group consisting of: BaPd 2 , BaPd 5 , NdPd, NdPd 3 , NdPd 5 , Nd 7 Pt 3 , Nd 3 Pt 2 , NdPt, Nd 3 Pt 4 , NdPt 2 , NdPt 5 , Bi 2 Nd, BiNd, Bi 3 Nd 4 , Bi 3 Nd 5 , BiNd 2 , Cd 2 Nd, CdNd, Mn 2 Nd, Mn 23 Nd 6 , Mn 12 Nd, Nd 5 Sb 3 , Nd 4 Sb 3 , NdSb, NdSb 2 , Fe 2 Nd, Fe 17 Nd 2 , Cs 3 Ge 2 , CsGe, CsGe 4 , Nd 5 Si 3 , Nd 5 Si 4 , NdSi, Nd 3 Si 4 , Nd 2 Si 3 , Nd 5 Si 9 , Cs 2 Te, NdTe 3 , Nd 2 Te 5 , NdTe 2 , Nd 4 Te 7 , Nd 2 Te 3 , Nd 3 , Te 4 , NdTe, Ce 3 Ir, Ce 2 Ir, Ce 55 Ir 45 , CeIr 2 , CeIr 3 , Ce 2 Ir 7 , CeIr 5 , CaPd, CaPd 2 , CaGe, Ca 2 Ge, GeNa 3 , GeNa, CaSi 2 , Ca 2 Si, CaSi, Se 2 Sr, Se 3 Sr 2 , SeSr, GeSr 2 , GeSr, Ge 2 Sr, SnSr, Sn 3 Sr 5 , SnSr 2 , Ce 2 Tl, Ce 5 Tl 3 , CeTl 3 , Ce 3 Tl 5 , CeTl, BaTl, Pd 13 Tl 9 , Pd 2 Tl, Pd 3 Tl, Mg 2 Si, Mg 2 Ge, BaPd 2 , BaPd 5 , Ce 4 Se 7 , Ce 3 Se 4 , Ce 2 Se 3 , CeSe, Ce 5 Se 3 , Ce 4 Ge 3 , Ce 5 Ge 4 , CeGe, Ce 3 Ge 5 , Ce 5 Si 3 , Ce 3 Si 2 , Ce 5 Si 4 , CeSi, Ce 3 Si 5 , CeSi 2 , CeTe 3 , Ce 2 Te 5 , CeTe 2 , Ce 4 Te 7 , Ce 3 Te 4 , CeTe, La 3 Se 7 , LaSe 2 , La 4 Se 7 , La 2 Se 3 , La 3 Se 4 , LaSe, GeLa 3 , Ge 3 La 5 , Ge 3 La 4 , Ge 4 La 5 , GeLa, Ge 5 La 3 , BaSe 2 , Ba 2 Se 3 , BaSe, PdSe, Mo 3 Se 4 , MoSe 2 , Ba 2 Ge, BaGe 2 , BaGe, Ba 2 Te 3 , BaTe, Ge 2 Pd 5 , GePd 2 , Ge 9 , Pd 25 , GePd, Ge 3 Pt, Ge 3 Pt, Ge 3 Pt 2 , GePt, Ge 2 Pt 3 , GePt 2 , GePt 3 , Pu 3 Sn, Pu 5 Sn 3 , Pu 5 Sn 4 , Pu 8 Sn 7 , Pu 7 Sn 8 , PuSn 2 , PuSn 3 , Pt 5 Te 4 , Pt 4 Te 5 , PtTe 2 , GeNi, Ge 3 Ni 5 , Ge 2 Ni 5 , GeNi 3 , NiTe 0 .85, NiTe 0 .775, Cr 11 Ge 19 , CrGe, Cr 11 Ge 8 , Cr 5 Ge 3 , Cr 3 Ge, CrSi 2 , Cr 5 Si 3 , Cr 3 Si, Cr 5 Te 8 , Cr 4 Te 5 , Cr 3 Te 4 , Ge 3 Mn 5 , GeMn 2 , Mn 6 Si, Mn 9 Si 2 , Mn 3 Si, Mn 5 Si 2 , Mn 5 Si 3 , MnSi, Mn 11 Si 19 , Mn 2 Sn, Mn 3 .25 Sn, MnTe, Te 2 W, FeGe 2 , Fe 5 Ge 3 , Fe 3 Ge, Fe 2 Si, Fe 5 Si 3 , FeSi, FeSi 2 , Ge 2 Mo, Ge 41 Mo 23 , Ge 16 Mo 9 , Ge 23 Mo 13 , Ge 3 Mo 5 , GeMo 3 , Mo 3 Si, Mo 5 Si 3 , MoSi 2 , MoSn, MoSn 2 , Mo 3 Te 4 , MoTe 2 , Si 2 Ti, SiTi, Si 4 , Ti 5 , Si 3 Ti 5 , SiTi 3 , Sn 5 Ti 6 , Sn 3 Ti 5 , SnTi 2 , SnTi 3 , CoGe 2 , Co 5 Ge 7 , CoGe, Co 5 Ge 3 , Co 4 Ge, Co 3 Te 4 , Ge 7 Re 3 , Re 5 Si 3 , ReSi, ReSi 2 , and Re 2 Te.

Claim 14

The information recording medium according to claim 11, wherein the substrate is transparent and has concavities or convexities for recording information, and the superresolution readout thin film has a reflective layer formed thereon.

Claim 15

The information recording medium according to claim 11, wherein the substrate is transparent and has concavities or convexities for recording information, and a protective layer is provided between the transparent substrate and the superresolution readout thin film.

Claim 16

The information recording medium according to claim 11, further comprising an intermediate layer provided on the superresolution readout thin film and a reflective layer provided on the intermediate layer.

Claim 17

The information recording medium according to claim 11, wherein the substrate is transparent, an information recording film is provided on said superresolution readout thin film and a reflective layer is provided on said information recording film.

Claim 18

The information recording medium according to claim 11, wherein the substrate is transparent and a protective layer is provided between the transparent substrate and the superresolution readout thin film.

Claim 19

The information recording medium according to claim 11, further comprising an information recording layer provided on said superresolution readout thin film, a reflective layer provided on said information recording layer, and an intermediate layer provided between at least one of said information recording layer and said superresolution readout thin film, and said reflective layer and said information recording layer.

Claim 20

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≦k/(j+k)≦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 2 Te 4 and at least one selected from the group consisting of Sn, Pb, Sb, Te, Zn, Cd, Se, In, Ga, S, Tl, Mg, Tl 2 Se, TlSe, Tl 2 Se 3 , Tl 3 Te 2 , TlTe, InBi, In 2 Bi, TeBi, Tl--Se, Tl--Te, PB--Sn, Bi--Sn, Se--Te, S--Se, Bi--Ga, Sn--Zn, Ga--Sn, Ga--In, In 3 SeTe 2 , AgInTe 2 , GeSb 4 Te 7 , Ge 2 Sb 2 Te 5 , GeBi 4 Te 7 , GeBi 2 Te 4 , Ge 3 Bi 2 Te 6 , Sn 2 Sb 6 Se 11 , Sn 2 Sb 2 Se 5 , SnSb 2 Te 4 , Pb 2 Sb 6 Te 11 , CuAsSe 2 , Cu 3 AsSe 3 , CuSbS 2 , CuSbSe 2 , InSe, Sb 2 Se 3 , Sb 2 Te 3 , Bi 2 Te 3 , SnSb, FeTe, Fe 2 Te 3 , FeTe 2 , ZnSb, Zn 3 Sb 2 , VTe 2 , V 5 Te 8 , AgIn 2 , BiSe, InSb, In 2 Te, In 2 Te 5 , Ba 4 Tl, Cd 11 Nd, Ba 13 Tl, Cd 6 Nd, and Ba 2 Tl, and H is at least one selected from the group consisting of: BaPd 2 , BaPd 5 , NdPd, NdPd 3 , NdPd 5 , Nd 7 Pt 3 , Nd 3 Pt 2 , NdPt, Nd 3 Pt 4 , NdPt 2 , NdPt 5 , Bi 2 Nd, BiNd, Bi 3 Nd 4 , Bi 3 Nd 5 , BiNd 2 , Cd 2 Nd, CdNd, Mn 2 Nd, Mn 23 Nd 6 , Mn 12 Nd, Nd 5 Sb 3 , Nd 4 Sb 3 , NdSb, NdSb 2 , Fe 2 Nd, Fe 17 Nd 2 , Cs 3 Ge 2 , CsGe, CsGe 4 , Nd 5 Si 3 , Nd 5 Si 4 , NdSi, Nd 3 Si 4 , Nd 2 Si 3 , Nd 5 Si 9 , Cs 2 Te, NdTe 3 , Nd 2 Te 5 , NdTe 2 , Nd 4 Te 7 , Nd 2 Te 3 , Nd 3 , Te 4 , NdTe, Ce 3 Ir, Ce 2 Ir, Ce 55 Ir 45 , CeIr 2 , CeIr 3 , Ce 2 Ir 7 , CeIr 5 , CaPd, CaPd 2 , CaGe, Ca 2 Ge, GeNa 3 , GeNa, CaSi 2 , Ca 2 Si, CaSi, Se 2 Sr, Se 3 Sr 2 , SeSr, GeSr 2 , GeSr, Ge 2 Sr, SnSr, Sn 3 Sr 5 , SnSr 2 , Ce 2 Tl, Ce 5 Tl 3 , CeTl 3 , Ce 3 Tl 5 , CeTl, BaTl, Pd 13 Tl 9 , Pd 2 Tl, Pd 3 Tl, Mg 2 Si, Mg 2 Ge, BaPd 2 , BaPd 5 , Ce 4 Se 7 , Ce 3 Se 4 , Ce 2 Se 3 , CeSe, Ce 5 Se 3 , Ce 4 Ge 3 , Ce 5 Ge 4 , CeGe, Ce 3 Ge 5 , Ce 5 Si 3 , Ce 3 Si 2 , Ce 5 Si 4 , CeSi, Ce 3 Si 5 , CeSi 2 , CeTe 3 , Ce 2 Te 5 , CeTe 2 , Ce 4 Te 7 , Ce 3 Te 4 , CeTe, La 3 Se 7 , LaSe 2 , La 4 Se 7 , La 2 Se 3 , La 3 Se 4 , LaSe, GeLa 3 , Ge 3 La 5 , Ge 3 La 4 , Ge 4 La 5 , GeLa, Ge 5 La 3 , BaSe 2 , Ba 2 Se 3 , BaSe, PdSe, Mo 3 Se 4 , MoSe 2 , Ba 2 Ge, BaGe 2 , BaGe, Ba 2 Te 3 , BaTe, Ge 2 Pd 5 , GePd 2 , Ge 9 , Pd 25 , GePd, Ge 3 Pt, Ge 3 Pt, Ge 3 Pt 2 , GePt, Ge 2 Pt 3 , GePt 2 , GePt 3 , Pu 3 Sn, Pu 5 Sn 3 , Pu 5 Sn 4 , Pu 8 Sn 7 , Pu 7 Sn 8 , PuSn 2 , PuSn 3 , Pt 5 Te 4 , Pt 4 Te 5 , PtTe 2 , GeNi, Ge 3 Ni 5 , Ge 2 Ni 5 , GeNi 3 , NiTe 0 .85, NiTe 0 .775, Cr 11 Ge 19 , CrGe, Cr 11 Ge 8 , Cr 5 Ge 3 , Cr 3 Ge, CrSi 2 , Cr 5 Si 3 , Cr 3 Si, Cr 5 Te 8 , Cr 4 Te 5 , Cr 3 Te 4 , Ge 3 Mn 5 , GeMn 2 , Mn 6 Si, Mn 9 Si 2 , Mn 3 Si, Mn 5 Si 2 , Mn 5 Si 3 , MnSi, Mn 11 Si 19 , Mn 2 Sn, Mn 3 .25 Sn, MnTe, Te 2 W, FeGe 2 , Fe 5 Ge 3 , Fe 3 Ge, Fe 2 Si, Fe 5 Si 3 , FeSi, FeSi 2 , Ge 2 Mo, Ge 41 Mo 23 , Ge 16 Mo 9 , Ge 23 Mo 13 , Ge 3 Mo 5 , GeMo 3 , Mo 3 Si, Mo 5 Si 3 , MoSi 2 , MoSn, MoSn 2 , Mo 3 Te 4 , MoTe 2 , Si 2 Ti, SiTi, Si 4 , Ti 5 , Si 3 Ti 5 , SiTi 3 , Sn 5 Ti 6 , Sn 3 Ti 5 , SnTi 2 , SnTi 3 , CoGe 2 , Co 5 Ge 7 , CoGe, Co 5 Ge 3 , Co 4 Ge, Co 3 Te 4 , Ge 7 Re 3 , Re 5 Si 3 , ReSi, ReSi 2 , and Re 2 Te.

Claim 21

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≦k/(j+k)≦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 2 Te 4 and at least one selected from the group consisting of Sn, Pb, Sb, Te, Zn, Cd, Se, In, Ga, S, Tl, Mg, Tl 2 Se, TlSe, Tl 2 Se 3 , Tl 3 Te 2 , TlTe, InBi, In 2 Bi, TeBi, Tl--Se, Tl--Te, PB--Sn, Bi--Sn, Se--Te, S--Se, Bi--Ga, Sn--Zn, Ga--Sn, Ga--In, In 3 SeTe 2 , AgInTe 2 , GeSb 4 Te 7 , Ge 2 Sb 2 Te 5 , GeBi 4 Te 7 , GeBi 2 Te 4 , Ge 3 Bi 2 Te 6 , Sn 2 Sb 6 Se 11 , Sn 2 Sb 2 Se 5 , SnSb 2 Te 4 , Pb 2 Sb 6 Te 11 , CuAsSe 2 , Cu 3 AsSe 3 , CuSbS 2 , CuSbSe 2 , InSe, Sb 2 Se 3 , Sb 2 Te 3 , Bi 2 Te 3 , SnSb, FeTe, Fe 2 Te 3 , FeTe 2 , ZnSb, Zn 3 Sb 2 , VTe 2 , V 5 Te 8 , AgIn 2 , BiSe, InSb, In 2 Te, In 2 Te 5 , Ba 4 Tl, Cd 11 Nd, Ba 13 Tl, Cd 6 Nd, and Ba 2 Tl, and H is at least one selected from the group consisting of: BaPd 2 , BaPd 5 , NdPd, NdPd 3 , NdPd 5 , Nd 7 Pt 3 , Nd 3 Pt 2 , NdPt, Nd 3 Pt 4 , NdPt 2 , NdPt 5 , Bi 2 Nd, BiNd, Bi 3 Nd 4 , Bi 3 Nd 5 , BiNd 2 , Cd 2 Nd, CdNd, Mn 2 Nd, Mn 23 Nd 6 , Mn 12 Nd, Nd 5 Sb 3 , Nd 4 Sb 3 , NdSb, NdSb 2 , Fe 2 Nd, Fe 17 Nd 2 , Cs 3 Ge 2 , CsGe, CsGe 4 , Nd 5 Si 3 , Nd 5 Si 4 , NdSi, Nd 3 Si 4 , Nd 2 Si 3 , Nd 5 Si 9 , Cs 2 Te, NdTe 3 , Nd 2 Te 5 , NdTe 2 , Nd 4 Te 7 , Nd 2 Te 3 , Nd 3 , Te 4 , NdTe, Ce 3 Ir, Ce 2 Ir, Ce 55 Ir 45 , CeIr 2 , CeIr 3 , Ce 2 Ir 7 , CeIr 5 , CaPd, CaPd 2 , CaGe, Ca 2 Ge, GeNa 3 , GeNa, CaSi 2 , Ca 2 Si, CaSi, Se 2 Sr, Se 3 Sr 2 , SeSr, GeSr 2 , GeSr, Ge 2 Sr, SnSr, Sn 3 Sr 5 , SnSr 2 , Ce 2 Tl, Ce 5 Tl 3 , CeTl 3 , Ce 3 Tl 5 , CeTl, BaTl, Pd 13 Tl 9 , Pd 2 Tl, Pd 3 Tl, Mg 2 Si, Mg 2 Ge, BaPd 2 , BaPd 5 , Ce 4 Se 7 , Ce 3 Se 4 , Ce 2 Se 3 , CeSe, Ce 5 Se 3 , Ce 4 Ge 3 , Ce 5 Ge 4 , CeGe, Ce 3 Ge 5 , Ce 5 Si 3 , Ce 3 Si 2 , Ce 5 Si 4 , CeSi, Ce 3 Si 5 , CeSi 2 , CeTe 3 , Ce 2 Te 5 , CeTe 2 , Ce 4 Te 7 , Ce 3 Te 4 , CeTe, La 3 Se 7 , LaSe 2 , La 4 Se 7 , La 2 Se 3 , La 3 Se 4 , LaSe, GeLa 3 , Ge 3 La 5 , Ge 3 La 4 , Ge 4 La 5 , GeLa, Ge 5 La 3 , BaSe 2 , Ba 2 Se 3 , BaSe, PdSe, Mo 3 Se 4 , MoSe 2 , Ba 2 Ge, BaGe 2 , BaGe, Ba 2 Te 3 , BaTe, Ge 2 Pd 5 , GePd 2 , Ge 9 , Pd 25 , GePd, Ge 3 Pt, Ge 3 Pt, Ge 3 Pt 2 , GePt, Ge 2 Pt 3 , GePt 2 , GePt 3 , Pu 3 Sn, Pu 5 Sn 3 , Pu 5 Sn 4 , Pu 8 Sn 7 , Pu 7 Sn 8 , PuSn 2 , PuSn 3 , Pt 5 Te 4 , Pt 4 Te 5 , PtTe 2 , GeNi, Ge 3 Ni 5 , Ge 2 Ni 5 , GeNi 3 , NiTe 0 .85, NiTe 0 .775, Cr 11 Ge 19 , CrGe, Cr 11 Ge 8 , Cr 5 Ge 3 , Cr 3 Ge, CrSi 2 , Cr 5 Si 3 , Cr 3 Si, Cr 5 Te 8 , Cr 4 Te 5 , Cr 3 Te 4 , Ge 3 Mn 5 , GeMn 2 , Mn 6 Si, Mn 9 Si 2 , Mn 3 Si, Mn 5 Si 2 , Mn 5 Si 3 , MnSi, Mn 11 Si 19 , Mn 2 Sn, Mn 3 .25 Sn, MnTe, Te 2 W, FeGe 2 , Fe 5 Ge 3 , Fe 3 Ge, Fe 2 Si, Fe 5 Si 3 , FeSi, FeSi 2 , Ge 2 Mo, Ge 41 Mo 23 , Ge 16 Mo 9 , Ge 23 Mo 13 , Ge 3 Mo 5 , GeMo 3 , Mo 3 Si, Mo 5 Si 3 , MoSi 2 , MoSn, MoSn 2 , Mo 3 Te 4 , MoTe 2 , Si 2 Ti, SiTi, Si 4 , Ti 5 , Si 3 Ti 5 , SiTi 3 , Sn 5 Ti 6 , Sn 3 Ti 5 , SnTi 2 , SnTi 3 , CoGe 2 , Co 5 Ge 7 , CoGe, Co 5 Ge 3 , Co 4 Ge, Co 3 Te 4 , Ge 7 Re 3 , Re 5 Si 3 , ReSi, ReSi 2 , and Re 2 Te.

Claim 22

A superresolution readout apparatus according to claim 18, further comprising means for detecting a disturbance of power distribution of the reflected light during superresolution readout, and means for controlling the power of the laser beam in response to the disturbance.

Claim 23

A superresolution readout apparatus according to claim 18 the laser beam is pulsating light, and relationships 0.4 λ/NA≦vT 1.5 λ/NA, and 0.3 k≦x/T≦0.5k are met, where k is a proportion constant, T is a period of the laser pulses, v is the linear velocity, λ/NA is the spot diameter, and x is the pulse width.

Claim 24

A superresolution readout apparatus according to claim 18, further comprising means for setting an output power of the laser beam at which the whole superresolution readout thin film cannot be melted even in a region of maximum temperatures thereof.