Abstract

Ni80Nb20-MgO multilayers with d spacing that varies from 2.50 to 3.07 nm were prepared by pulsed laser deposition under conditions of ultrahigh vacuum (UHV) and argon. The morphological and atomic structure in the multilayers was determined by hard-x-ray scattering. It was found that the interface roughness in both cases, UHV and argon deposition, is <0.4 nm, whereas the lateral and longitudinal correlation lengths in the case of argon deposition, 5.0 and 1.0 nm, respectively, are an order of magnitude lower. This is due to a reduction in kinetic energy of the condensing species in argon by orders of magnitude due to multiple collisions, which reduces the lateral relaxation probability. Hence the soft-x-ray reflectance of [Ni80Nb20-MgO]10 multilayers deposited in argon was determined at 413 eV (3.00 nm), middle of the water window. The reflectance has a peak at ∼35.2° with a half-width of 3.5° and 0.19% maximum value. These results agree well with the simulation results performed by use of the structural parameters obtained from hard-x-ray scattering. The atomic structure determined by high-angle x-ray diffraction shows that both Ni80Nb20 and MgO are amorphous in the as-deposited condition.

© 2003 Optical Society of America

Full Article  |  PDF Article

References

  • View by:
  • |
  • |
  • |

  1. J. Kirz, C. Jacobsen, M. Howells, “Soft x-ray microscopes and their biological applications,” Q. Rev. Biophys. 28, 33–130 (1995).
    [CrossRef] [PubMed]
  2. S. Vitta, T. H. Metzger, J. Peisl, “Structure and normal incidence soft-x-ray reflectivity of Ni-Nb/C amorphous multilayers,” Appl. Opt. 36, 1472–1481 (1997).
    [CrossRef] [PubMed]
  3. S. Vitta, P. Yang, “Thermal stability of 2.4 nm period Ni-Nb/C multilayer x-ray mirror,” Appl. Phys. Lett. 77, 3654–3656 (2000).
    [CrossRef]
  4. N. N. Salashchenko, E. A. Shamov, “Short period x-ray multilayers based on Cr/Sc,” Opt. Commun. 134, 7–10 (1997).
    [CrossRef]
  5. F. Schafers, M. Mertin, D. Abramsohn, A. Gaupp, H.-Ch. Mertins, N. N. Salashchenko, “Cr/Sc nanolayers for the water window: improved performance,” Nucl. Instrum. Methods Phys. Res. A 467–468, 349–353 (2001).
    [CrossRef]
  6. T. B. Massalski, ed., Binary Alloy Phase Diagrams (American Society of Metals, Materials Park, Ohio, 1986).
  7. S. Vitta, “The limits of glass formation by pulsed laser quenching,” Scr. Metall. Mater. 25, 2209–2214 (1991).
    [CrossRef]
  8. X. Y. Chen, K. H. Wong, C. L. Mak, X. B. Yin, M. Wang, L. M. Liu, Z. G. Liu, “Selective growth of (100)-, (110)-, and (111)-oriented MgO films on Si(100) by pulsed laser deposition,” J. Appl. Phys. 91, 5728–5734 (2002).
    [CrossRef]
  9. Data are available at http://www-cxro.lbl.gov .
  10. D. L. Windt, “IMD—software for modeling the optical properties of multilayers,” Comput. Phys. 12, 360–370 (1998).
    [CrossRef]
  11. S. Vitta, M. Weisheit, T. Scharf, H.-U. Krebs, “Alloy-ceramic oxide multilayer mirrors for water-window soft x rays,” Opt. Lett. 26, 1448–1459 (2001).
    [CrossRef]
  12. H.-U. Krebs, “Characteristic properties of laser deposited metallic systems,” Int. J. Non-Equilibrium Process. 10, 3–25 (1997).
  13. L. Nevot, P. Croce, “Characterisation des surfaces par reflexion rasante de rayons X,” Rev. Phys. Appl. 15, 761–779 (1980).
    [CrossRef]
  14. K.-H. Mueller, “Dependence of thin-film microstructure on deposition rate by means of a computer simulation,” J. Appl. Phys. 58, 2573–2576 (1985).
    [CrossRef]
  15. S. K. Sinha, E. B. Sirota, S. Garoff, H. B. Stanley, “X-ray and neutron scattering from rough surfaces,” Phys. Rev. B 38, 2297–2311 (1988).
    [CrossRef]
  16. T. Salditt, T. H. Metzger, Ch. Brandt, U. Klemradt, J. Peisl, “Determination of the static scaling exponent of self-affine interfaces by nonspecular x-ray scattering,” Phys. Rev. B 51, 5617–5627 (1995).
    [CrossRef]
  17. A.-L. Barabasi, H. E. Stanley, Fractal Concepts in Surface Growth (Cambridge U. Press, Cambridge, England, 1995).
    [CrossRef]
  18. Y. Nakata, J. Muramoto, T. Okada, M. Maeda, “Particle dynamics during nanoparticle synthesis by laser ablation in a background gas,” J. Appl. Phys. 91, 1640–1643 (2002).
    [CrossRef]

2002 (2)

X. Y. Chen, K. H. Wong, C. L. Mak, X. B. Yin, M. Wang, L. M. Liu, Z. G. Liu, “Selective growth of (100)-, (110)-, and (111)-oriented MgO films on Si(100) by pulsed laser deposition,” J. Appl. Phys. 91, 5728–5734 (2002).
[CrossRef]

Y. Nakata, J. Muramoto, T. Okada, M. Maeda, “Particle dynamics during nanoparticle synthesis by laser ablation in a background gas,” J. Appl. Phys. 91, 1640–1643 (2002).
[CrossRef]

2001 (2)

S. Vitta, M. Weisheit, T. Scharf, H.-U. Krebs, “Alloy-ceramic oxide multilayer mirrors for water-window soft x rays,” Opt. Lett. 26, 1448–1459 (2001).
[CrossRef]

F. Schafers, M. Mertin, D. Abramsohn, A. Gaupp, H.-Ch. Mertins, N. N. Salashchenko, “Cr/Sc nanolayers for the water window: improved performance,” Nucl. Instrum. Methods Phys. Res. A 467–468, 349–353 (2001).
[CrossRef]

2000 (1)

S. Vitta, P. Yang, “Thermal stability of 2.4 nm period Ni-Nb/C multilayer x-ray mirror,” Appl. Phys. Lett. 77, 3654–3656 (2000).
[CrossRef]

1998 (1)

D. L. Windt, “IMD—software for modeling the optical properties of multilayers,” Comput. Phys. 12, 360–370 (1998).
[CrossRef]

1997 (3)

N. N. Salashchenko, E. A. Shamov, “Short period x-ray multilayers based on Cr/Sc,” Opt. Commun. 134, 7–10 (1997).
[CrossRef]

S. Vitta, T. H. Metzger, J. Peisl, “Structure and normal incidence soft-x-ray reflectivity of Ni-Nb/C amorphous multilayers,” Appl. Opt. 36, 1472–1481 (1997).
[CrossRef] [PubMed]

H.-U. Krebs, “Characteristic properties of laser deposited metallic systems,” Int. J. Non-Equilibrium Process. 10, 3–25 (1997).

1995 (2)

T. Salditt, T. H. Metzger, Ch. Brandt, U. Klemradt, J. Peisl, “Determination of the static scaling exponent of self-affine interfaces by nonspecular x-ray scattering,” Phys. Rev. B 51, 5617–5627 (1995).
[CrossRef]

J. Kirz, C. Jacobsen, M. Howells, “Soft x-ray microscopes and their biological applications,” Q. Rev. Biophys. 28, 33–130 (1995).
[CrossRef] [PubMed]

1991 (1)

S. Vitta, “The limits of glass formation by pulsed laser quenching,” Scr. Metall. Mater. 25, 2209–2214 (1991).
[CrossRef]

1988 (1)

S. K. Sinha, E. B. Sirota, S. Garoff, H. B. Stanley, “X-ray and neutron scattering from rough surfaces,” Phys. Rev. B 38, 2297–2311 (1988).
[CrossRef]

1985 (1)

K.-H. Mueller, “Dependence of thin-film microstructure on deposition rate by means of a computer simulation,” J. Appl. Phys. 58, 2573–2576 (1985).
[CrossRef]

1980 (1)

L. Nevot, P. Croce, “Characterisation des surfaces par reflexion rasante de rayons X,” Rev. Phys. Appl. 15, 761–779 (1980).
[CrossRef]

Abramsohn, D.

F. Schafers, M. Mertin, D. Abramsohn, A. Gaupp, H.-Ch. Mertins, N. N. Salashchenko, “Cr/Sc nanolayers for the water window: improved performance,” Nucl. Instrum. Methods Phys. Res. A 467–468, 349–353 (2001).
[CrossRef]

Barabasi, A.-L.

A.-L. Barabasi, H. E. Stanley, Fractal Concepts in Surface Growth (Cambridge U. Press, Cambridge, England, 1995).
[CrossRef]

Brandt, Ch.

T. Salditt, T. H. Metzger, Ch. Brandt, U. Klemradt, J. Peisl, “Determination of the static scaling exponent of self-affine interfaces by nonspecular x-ray scattering,” Phys. Rev. B 51, 5617–5627 (1995).
[CrossRef]

Chen, X. Y.

X. Y. Chen, K. H. Wong, C. L. Mak, X. B. Yin, M. Wang, L. M. Liu, Z. G. Liu, “Selective growth of (100)-, (110)-, and (111)-oriented MgO films on Si(100) by pulsed laser deposition,” J. Appl. Phys. 91, 5728–5734 (2002).
[CrossRef]

Croce, P.

L. Nevot, P. Croce, “Characterisation des surfaces par reflexion rasante de rayons X,” Rev. Phys. Appl. 15, 761–779 (1980).
[CrossRef]

Garoff, S.

S. K. Sinha, E. B. Sirota, S. Garoff, H. B. Stanley, “X-ray and neutron scattering from rough surfaces,” Phys. Rev. B 38, 2297–2311 (1988).
[CrossRef]

Gaupp, A.

F. Schafers, M. Mertin, D. Abramsohn, A. Gaupp, H.-Ch. Mertins, N. N. Salashchenko, “Cr/Sc nanolayers for the water window: improved performance,” Nucl. Instrum. Methods Phys. Res. A 467–468, 349–353 (2001).
[CrossRef]

Howells, M.

J. Kirz, C. Jacobsen, M. Howells, “Soft x-ray microscopes and their biological applications,” Q. Rev. Biophys. 28, 33–130 (1995).
[CrossRef] [PubMed]

Jacobsen, C.

J. Kirz, C. Jacobsen, M. Howells, “Soft x-ray microscopes and their biological applications,” Q. Rev. Biophys. 28, 33–130 (1995).
[CrossRef] [PubMed]

Kirz, J.

J. Kirz, C. Jacobsen, M. Howells, “Soft x-ray microscopes and their biological applications,” Q. Rev. Biophys. 28, 33–130 (1995).
[CrossRef] [PubMed]

Klemradt, U.

T. Salditt, T. H. Metzger, Ch. Brandt, U. Klemradt, J. Peisl, “Determination of the static scaling exponent of self-affine interfaces by nonspecular x-ray scattering,” Phys. Rev. B 51, 5617–5627 (1995).
[CrossRef]

Krebs, H.-U.

S. Vitta, M. Weisheit, T. Scharf, H.-U. Krebs, “Alloy-ceramic oxide multilayer mirrors for water-window soft x rays,” Opt. Lett. 26, 1448–1459 (2001).
[CrossRef]

H.-U. Krebs, “Characteristic properties of laser deposited metallic systems,” Int. J. Non-Equilibrium Process. 10, 3–25 (1997).

Liu, L. M.

X. Y. Chen, K. H. Wong, C. L. Mak, X. B. Yin, M. Wang, L. M. Liu, Z. G. Liu, “Selective growth of (100)-, (110)-, and (111)-oriented MgO films on Si(100) by pulsed laser deposition,” J. Appl. Phys. 91, 5728–5734 (2002).
[CrossRef]

Liu, Z. G.

X. Y. Chen, K. H. Wong, C. L. Mak, X. B. Yin, M. Wang, L. M. Liu, Z. G. Liu, “Selective growth of (100)-, (110)-, and (111)-oriented MgO films on Si(100) by pulsed laser deposition,” J. Appl. Phys. 91, 5728–5734 (2002).
[CrossRef]

Maeda, M.

Y. Nakata, J. Muramoto, T. Okada, M. Maeda, “Particle dynamics during nanoparticle synthesis by laser ablation in a background gas,” J. Appl. Phys. 91, 1640–1643 (2002).
[CrossRef]

Mak, C. L.

X. Y. Chen, K. H. Wong, C. L. Mak, X. B. Yin, M. Wang, L. M. Liu, Z. G. Liu, “Selective growth of (100)-, (110)-, and (111)-oriented MgO films on Si(100) by pulsed laser deposition,” J. Appl. Phys. 91, 5728–5734 (2002).
[CrossRef]

Mertin, M.

F. Schafers, M. Mertin, D. Abramsohn, A. Gaupp, H.-Ch. Mertins, N. N. Salashchenko, “Cr/Sc nanolayers for the water window: improved performance,” Nucl. Instrum. Methods Phys. Res. A 467–468, 349–353 (2001).
[CrossRef]

Mertins, H.-Ch.

F. Schafers, M. Mertin, D. Abramsohn, A. Gaupp, H.-Ch. Mertins, N. N. Salashchenko, “Cr/Sc nanolayers for the water window: improved performance,” Nucl. Instrum. Methods Phys. Res. A 467–468, 349–353 (2001).
[CrossRef]

Metzger, T. H.

S. Vitta, T. H. Metzger, J. Peisl, “Structure and normal incidence soft-x-ray reflectivity of Ni-Nb/C amorphous multilayers,” Appl. Opt. 36, 1472–1481 (1997).
[CrossRef] [PubMed]

T. Salditt, T. H. Metzger, Ch. Brandt, U. Klemradt, J. Peisl, “Determination of the static scaling exponent of self-affine interfaces by nonspecular x-ray scattering,” Phys. Rev. B 51, 5617–5627 (1995).
[CrossRef]

Mueller, K.-H.

K.-H. Mueller, “Dependence of thin-film microstructure on deposition rate by means of a computer simulation,” J. Appl. Phys. 58, 2573–2576 (1985).
[CrossRef]

Muramoto, J.

Y. Nakata, J. Muramoto, T. Okada, M. Maeda, “Particle dynamics during nanoparticle synthesis by laser ablation in a background gas,” J. Appl. Phys. 91, 1640–1643 (2002).
[CrossRef]

Nakata, Y.

Y. Nakata, J. Muramoto, T. Okada, M. Maeda, “Particle dynamics during nanoparticle synthesis by laser ablation in a background gas,” J. Appl. Phys. 91, 1640–1643 (2002).
[CrossRef]

Nevot, L.

L. Nevot, P. Croce, “Characterisation des surfaces par reflexion rasante de rayons X,” Rev. Phys. Appl. 15, 761–779 (1980).
[CrossRef]

Okada, T.

Y. Nakata, J. Muramoto, T. Okada, M. Maeda, “Particle dynamics during nanoparticle synthesis by laser ablation in a background gas,” J. Appl. Phys. 91, 1640–1643 (2002).
[CrossRef]

Peisl, J.

S. Vitta, T. H. Metzger, J. Peisl, “Structure and normal incidence soft-x-ray reflectivity of Ni-Nb/C amorphous multilayers,” Appl. Opt. 36, 1472–1481 (1997).
[CrossRef] [PubMed]

T. Salditt, T. H. Metzger, Ch. Brandt, U. Klemradt, J. Peisl, “Determination of the static scaling exponent of self-affine interfaces by nonspecular x-ray scattering,” Phys. Rev. B 51, 5617–5627 (1995).
[CrossRef]

Salashchenko, N. N.

F. Schafers, M. Mertin, D. Abramsohn, A. Gaupp, H.-Ch. Mertins, N. N. Salashchenko, “Cr/Sc nanolayers for the water window: improved performance,” Nucl. Instrum. Methods Phys. Res. A 467–468, 349–353 (2001).
[CrossRef]

N. N. Salashchenko, E. A. Shamov, “Short period x-ray multilayers based on Cr/Sc,” Opt. Commun. 134, 7–10 (1997).
[CrossRef]

Salditt, T.

T. Salditt, T. H. Metzger, Ch. Brandt, U. Klemradt, J. Peisl, “Determination of the static scaling exponent of self-affine interfaces by nonspecular x-ray scattering,” Phys. Rev. B 51, 5617–5627 (1995).
[CrossRef]

Schafers, F.

F. Schafers, M. Mertin, D. Abramsohn, A. Gaupp, H.-Ch. Mertins, N. N. Salashchenko, “Cr/Sc nanolayers for the water window: improved performance,” Nucl. Instrum. Methods Phys. Res. A 467–468, 349–353 (2001).
[CrossRef]

Scharf, T.

Shamov, E. A.

N. N. Salashchenko, E. A. Shamov, “Short period x-ray multilayers based on Cr/Sc,” Opt. Commun. 134, 7–10 (1997).
[CrossRef]

Sinha, S. K.

S. K. Sinha, E. B. Sirota, S. Garoff, H. B. Stanley, “X-ray and neutron scattering from rough surfaces,” Phys. Rev. B 38, 2297–2311 (1988).
[CrossRef]

Sirota, E. B.

S. K. Sinha, E. B. Sirota, S. Garoff, H. B. Stanley, “X-ray and neutron scattering from rough surfaces,” Phys. Rev. B 38, 2297–2311 (1988).
[CrossRef]

Stanley, H. B.

S. K. Sinha, E. B. Sirota, S. Garoff, H. B. Stanley, “X-ray and neutron scattering from rough surfaces,” Phys. Rev. B 38, 2297–2311 (1988).
[CrossRef]

Stanley, H. E.

A.-L. Barabasi, H. E. Stanley, Fractal Concepts in Surface Growth (Cambridge U. Press, Cambridge, England, 1995).
[CrossRef]

Vitta, S.

S. Vitta, M. Weisheit, T. Scharf, H.-U. Krebs, “Alloy-ceramic oxide multilayer mirrors for water-window soft x rays,” Opt. Lett. 26, 1448–1459 (2001).
[CrossRef]

S. Vitta, P. Yang, “Thermal stability of 2.4 nm period Ni-Nb/C multilayer x-ray mirror,” Appl. Phys. Lett. 77, 3654–3656 (2000).
[CrossRef]

S. Vitta, T. H. Metzger, J. Peisl, “Structure and normal incidence soft-x-ray reflectivity of Ni-Nb/C amorphous multilayers,” Appl. Opt. 36, 1472–1481 (1997).
[CrossRef] [PubMed]

S. Vitta, “The limits of glass formation by pulsed laser quenching,” Scr. Metall. Mater. 25, 2209–2214 (1991).
[CrossRef]

Wang, M.

X. Y. Chen, K. H. Wong, C. L. Mak, X. B. Yin, M. Wang, L. M. Liu, Z. G. Liu, “Selective growth of (100)-, (110)-, and (111)-oriented MgO films on Si(100) by pulsed laser deposition,” J. Appl. Phys. 91, 5728–5734 (2002).
[CrossRef]

Weisheit, M.

Windt, D. L.

D. L. Windt, “IMD—software for modeling the optical properties of multilayers,” Comput. Phys. 12, 360–370 (1998).
[CrossRef]

Wong, K. H.

X. Y. Chen, K. H. Wong, C. L. Mak, X. B. Yin, M. Wang, L. M. Liu, Z. G. Liu, “Selective growth of (100)-, (110)-, and (111)-oriented MgO films on Si(100) by pulsed laser deposition,” J. Appl. Phys. 91, 5728–5734 (2002).
[CrossRef]

Yang, P.

S. Vitta, P. Yang, “Thermal stability of 2.4 nm period Ni-Nb/C multilayer x-ray mirror,” Appl. Phys. Lett. 77, 3654–3656 (2000).
[CrossRef]

Yin, X. B.

X. Y. Chen, K. H. Wong, C. L. Mak, X. B. Yin, M. Wang, L. M. Liu, Z. G. Liu, “Selective growth of (100)-, (110)-, and (111)-oriented MgO films on Si(100) by pulsed laser deposition,” J. Appl. Phys. 91, 5728–5734 (2002).
[CrossRef]

Appl. Opt. (1)

Appl. Phys. Lett. (1)

S. Vitta, P. Yang, “Thermal stability of 2.4 nm period Ni-Nb/C multilayer x-ray mirror,” Appl. Phys. Lett. 77, 3654–3656 (2000).
[CrossRef]

Comput. Phys. (1)

D. L. Windt, “IMD—software for modeling the optical properties of multilayers,” Comput. Phys. 12, 360–370 (1998).
[CrossRef]

Int. J. Non-Equilibrium Process. (1)

H.-U. Krebs, “Characteristic properties of laser deposited metallic systems,” Int. J. Non-Equilibrium Process. 10, 3–25 (1997).

J. Appl. Phys. (3)

K.-H. Mueller, “Dependence of thin-film microstructure on deposition rate by means of a computer simulation,” J. Appl. Phys. 58, 2573–2576 (1985).
[CrossRef]

X. Y. Chen, K. H. Wong, C. L. Mak, X. B. Yin, M. Wang, L. M. Liu, Z. G. Liu, “Selective growth of (100)-, (110)-, and (111)-oriented MgO films on Si(100) by pulsed laser deposition,” J. Appl. Phys. 91, 5728–5734 (2002).
[CrossRef]

Y. Nakata, J. Muramoto, T. Okada, M. Maeda, “Particle dynamics during nanoparticle synthesis by laser ablation in a background gas,” J. Appl. Phys. 91, 1640–1643 (2002).
[CrossRef]

Nucl. Instrum. Methods Phys. Res. A (1)

F. Schafers, M. Mertin, D. Abramsohn, A. Gaupp, H.-Ch. Mertins, N. N. Salashchenko, “Cr/Sc nanolayers for the water window: improved performance,” Nucl. Instrum. Methods Phys. Res. A 467–468, 349–353 (2001).
[CrossRef]

Opt. Commun. (1)

N. N. Salashchenko, E. A. Shamov, “Short period x-ray multilayers based on Cr/Sc,” Opt. Commun. 134, 7–10 (1997).
[CrossRef]

Opt. Lett. (1)

Phys. Rev. B (2)

S. K. Sinha, E. B. Sirota, S. Garoff, H. B. Stanley, “X-ray and neutron scattering from rough surfaces,” Phys. Rev. B 38, 2297–2311 (1988).
[CrossRef]

T. Salditt, T. H. Metzger, Ch. Brandt, U. Klemradt, J. Peisl, “Determination of the static scaling exponent of self-affine interfaces by nonspecular x-ray scattering,” Phys. Rev. B 51, 5617–5627 (1995).
[CrossRef]

Q. Rev. Biophys. (1)

J. Kirz, C. Jacobsen, M. Howells, “Soft x-ray microscopes and their biological applications,” Q. Rev. Biophys. 28, 33–130 (1995).
[CrossRef] [PubMed]

Rev. Phys. Appl. (1)

L. Nevot, P. Croce, “Characterisation des surfaces par reflexion rasante de rayons X,” Rev. Phys. Appl. 15, 761–779 (1980).
[CrossRef]

Scr. Metall. Mater. (1)

S. Vitta, “The limits of glass formation by pulsed laser quenching,” Scr. Metall. Mater. 25, 2209–2214 (1991).
[CrossRef]

Other (3)

Data are available at http://www-cxro.lbl.gov .

T. B. Massalski, ed., Binary Alloy Phase Diagrams (American Society of Metals, Materials Park, Ohio, 1986).

A.-L. Barabasi, H. E. Stanley, Fractal Concepts in Surface Growth (Cambridge U. Press, Cambridge, England, 1995).
[CrossRef]

Cited By

OSA participates in CrossRef's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (6)

Fig. 1
Fig. 1

Calculated maximum soft-x-ray reflectivity of Ni-Mg (circles) and Ni80Nb20-MgO (curve) multilayers at 3.0-nm wavelength as a function of an increased number of periods at an angle of 36.9° shows that they are comparable. The d spacing in both cases is 2.5 nm, and the multilayers are assumed to be ideal with no interface roughness.

Fig. 2
Fig. 2

Specular reflectivity (dotted curve) scan from the Ni80Nb20-MgO multilayers deposited in (a) UHV and (b) argon shows clear thickness oscillations together with the first-order Bragg peak. The longitudinal offset scans (solid curve), however, do not show a clear peak at the first-order Bragg peak position in the case of (b) argon deposition whereas they show a clear peak in the case of (a) UHV deposition, indicating a difference in the nature of interface roughness correlations. In (a) the top two curves are from 3.07-nm period multilayers and the lower curves are from 2.95-nm period multilayers. In (b) the top curves are from 2.67-nm period multilayers whereas the lower set of curves is from 2.50-nm period multilayers. The two sets of curves were shifted vertically for clarity in both (a) and (b).

Fig. 3
Fig. 3

Transverse rocking scans at the first-order Bragg peak position (filled circles) and prior to the Bragg peak position show significant diffuse scattering on either side of the central peak from Ni80Nb20-MgO multilayers deposited in (a) UHV whereas the multilayers deposited in (b) argon do not show significant diffuse scattering. These results clearly show that the interface morphology is different in the two cases. The two sets of curves in (a) and (b) are from multilayers with different periods as listed in Table 1. The curves represented by open circles are the rocking scans at a position before the first-order Bragg peak; the filled circles correspond to rocking scans at the first-order Bragg peak.

Fig. 4
Fig. 4

Soft-x-ray specular reflectance R in the angular range from 30° to 45° 2α (filled circles) from the [Ni80Nb20-MgO]10 multilayers deposited in argon shows a clear peak at ∼35.2° that corresponds to a spacing of 2.67 nm. The reflectance of an equivalent ideal multilayer is shown by open circles, and the curve is a simulation of the soft-x-ray reflectance obtained with the structural parameters listed in Table 1.

Fig. 5
Fig. 5

Simulated grazing-incidence specular scattering (solid curve) obtained by use of the parameters listed in Table 1 is in good agreement with the experimentally observed specular scattering (open circles) for both (a) UHV and (b) argon deposited Ni80Nb20-MgO multilayers. The interface roughness in all cases was <0.4 nm. The two sets of curves in (a) are from 21 period multilayers with 3.07-nm (top) and 2.95-nm (bottom) periods and in (b) from 10 period multilayers with 2.67-nm (top) and 2.50-nm (bottom) periods. The curves were shifted vertically in both (a) and (b) for clarity.

Fig. 6
Fig. 6

Grazing-incidence diffuse scattering simulation along the transverse direction (Q x ) shows that, for the Ni80Nb20-MgO multilayers deposited in (a) UHV, the lateral and longitudinal roughness correlation lengths, ξ and ξ, are an order of magnitude longer compared with those for multilayers deposited in (b) argon. The experimental results are represented by open circles and the simulation results by a solid curve. The two sets of curves in both (a) and (b) have different bilayer periods and are listed in Table 1.

Tables (1)

Tables Icon

Table 1 Various Ni80Nb20/MgO Multilayer Structural Parametersa

Equations (7)

Equations on this page are rendered with MathJax. Learn more.

Qx=in-plane transverse scattering vector =2π/λcos θi cos 2α-cos θe,
Qz=in-plane longitudinal scattering vector =2π/λsin θi+sin θe,
RQz=RidealQzexp-QzQzσ2,
RidealQz=Qz-Qz2-Qc2-32iπ2β/λ21/2Qz+Qz2-Qc2-32iπ2β/λ21/22,
SQ=|Δρ|AQz2exp-Qz2σ2 expQz2CX, Y-1×expiQxX+QyYdXdY,
CX, Y=σ2 exp-R/ξ2H,
hx, tt=υ2hx, t+ηx, t,

Metrics