Ferromagnetic Heusler Alloy Thin Films: Electronic Properties and Magnetic Moment Formation

  • Heike C. Herper
  • Peter Kratzer
  • Heiko Wende
  • Bernhard Krumme
  • Kurt Westerholt
  • Peter Entel
Chapter
Part of the Springer Tracts in Modern Physics book series (STMP, volume 246)

Abstract

Heusler alloys have attracted huge interest due to their outstanding magnetic properties which make them suitable for various applications. Bulk Heusler alloys are applied in magnetic shape memory and magneto-caloric devices. Here, we focus on thin films of Heusler alloys as needed for magneto-electronic applications. Especially, Co- or Fe-based systems such as Co\(_2\)MnSi are known to be half-metallic or have at least a high spin polarization and a high Curie temperature making them appropriate as spintronic materials. In the present paper the influence of composition, disorder, and structural deformation on the magnetic properties is discussed from experimental as well as theoretical point of view. Since the quality of a spintronic device crucially depends on the interplay between the ferromagnet and the substrate the influence of different substrates (GaAs, MgO) on the electronic and magnetic properties is studied.

Keywords

Spin Polarization Heusler Alloy Heusler Compound Magnetic Shape Memory Alloy High Spin Polarization 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

References

  1. 1.
    S. Maekawa, T. Shinjo (eds.), Spin Dependent Transport in Magnetic Nanostructures, Advances in Condensed Matter Science (Taylor & Francis, London, 2002)Google Scholar
  2. 2.
    N. Tran, T.J. Webster, J. Mater. Chem. 20, 8760 (2010)CrossRefGoogle Scholar
  3. 3.
    A. Ayuela, J. Enkovaara, K. Ullakko, R.M. Nieminen, J. Phys.: Condens. Matter. 11, 2017 (1999)Google Scholar
  4. 4.
    T. Mizuno, Y. Tsuchiya, T. Machita, S. Hara, D. Miyauchi, K. Shimazawa, T. Chou, K. Noguchi, K. Tagami, IEEE Trans. Magn. 44, 3584 (2008)ADSCrossRefGoogle Scholar
  5. 5.
    A. Kalitsov, M. Chshiev, I. Theodonis, M. Kioussis, W.H. Butler, Phys. Rev. B 79, 174416 (2009)ADSCrossRefGoogle Scholar
  6. 6.
    B. Krumme et al., Phys. Rev. B 80, 144403 (2009)ADSCrossRefGoogle Scholar
  7. 7.
    P. Mavropoulos, N. Papanikolaou, P.H. Dederichs, Phys. Rev. Lett. 85, 1088 (2000)ADSCrossRefGoogle Scholar
  8. 8.
    S. Chadov, G.H. Fecher, C. Felser, J. Minár, J. Braun, H. Ebert, J. Phys. D: Appl. Phys. 42, 084002 (2009)ADSCrossRefGoogle Scholar
  9. 9.
    P. Klaer, M. Kallmayer, C.G.F. Blum, T. Graf, J. Barth, B. Balke, G.H. Fecher, C. Felser, H.J. Elmers, Phys. Rev. B 80, 144405 (2009)ADSCrossRefGoogle Scholar
  10. 10.
    K. Tsuchiya, H. Nakamura, D. Ohtoyo, H. Nakayama, H. Ohtsuka, M. Umemoto, Int.. J. Mater. Prod. Technol. SPM1, 409 (2001)Google Scholar
  11. 11.
    G. Wu, C. Yu, L. Meng, J. Chen, F. Yang, S. Qi, W. Zhan, Z. Wang, Y. Zheng, C. Zhao, Appl. Phys. Lett. 75, 2990 (1999)ADSCrossRefGoogle Scholar
  12. 12.
    P. Entel, M.E. Gruner, A. Dannenberg, M. Siewert, S.K. Nayak, H.C. Herper, V.D. Buchelnikov, Mater. Sci. Forum 635, 3 (2010)CrossRefGoogle Scholar
  13. 13.
    A.N. Vasil’ev, A.D. Bozhko, V.V. Khovailo, I.E. Dikshtein, V.G. Shavrov, V.D. Buchelnikov, M. Matsumoto, S. Suzuki, T. Takagi, J. Tani, Phys. Rev. B 59, 1113 (1999)ADSCrossRefGoogle Scholar
  14. 14.
    S. Tsunegi, Y. Sakuraba, M. Oogane, K. Takanashi, Y. Ando, Appl. Phys. Lett. 93, 112506 (2008)ADSCrossRefGoogle Scholar
  15. 15.
    G.Q. Yu, L. Chen, S. Rizwan, J.H. Zhao, K. Xu, X.F. Han, Appl. Phys. Lett. 98, 262501 (2011)ADSCrossRefGoogle Scholar
  16. 16.
    K. Inomata, S. Okamura, A. Miyazaki, N. Tezuka, M. Wojcik, E. Jedryka, J. Phys. D: Appl. Phys. 39, 816 (2006)ADSCrossRefGoogle Scholar
  17. 17.
    X. Moya, L. Mañosa, A. Planes, S. Aksoy, M. Acet, E.F. Wassermann, T. Krenke, Phys. Rev. B 75, 184412 (2007)ADSCrossRefGoogle Scholar
  18. 18.
    J. Marcos, L. Mañosa, A. Planes, F. Casanova, X. Batlle, A. Labarta, B. Matínez, J. Phys. IV France 115, 105 (2004)CrossRefGoogle Scholar
  19. 19.
    S. Chadov, X.L. Qi, J. Kübler, G.H. Fecher, C. Felser, S.C. Zhang, Nat. Mater. 9, 541 (2010)ADSCrossRefGoogle Scholar
  20. 20.
    K. Ullakko, J. Huang, C. Kantner, R. O’Handley, V. Kokorin, Appl. Phys. Lett. 69, 1966 (1996)ADSCrossRefGoogle Scholar
  21. 21.
    O. Heczko, M. Thomas, R. Niemann, L. Schultz, S. Fähler, Appl. Phys. Lett. 94, 152513 (2009)ADSCrossRefGoogle Scholar
  22. 22.
    C.A. Jenkins, R. Ramesh, M. Huth, T. Eichhorn, P. Pörsch, H.J. Elmers, G. Jakob, Appl. Phys. Lett. 93, 234101 (2008)ADSCrossRefGoogle Scholar
  23. 23.
    S. Ghosh, B. Sanyal, J. Phys. Condens. Matter 22, 346001 (2010)CrossRefGoogle Scholar
  24. 24.
    S. Hamann et al., Acta Materialia 58, 5949 (2010)CrossRefGoogle Scholar
  25. 25.
    A. Planes, L. Mañosa, M. Acet, J. Phys.: Condens. Matter 21, 233201 (2009)Google Scholar
  26. 26.
    P. Entel, V.D. Buchelnikov, V.V. Khovailo, A.T. Zayak, W.A. Adeagbo, M.E. Gruner, H.C. Herper, E.F. Wassermann, J. Phys. D: Appl. Phys. 39, 865 (2006)ADSCrossRefGoogle Scholar
  27. 27.
    M. Gilleßen, R. Dronskowski, J. Comput. Chem. 30, 1290 (2008)CrossRefGoogle Scholar
  28. 28.
    A. Dannenberg, M. Siewert, M.E. Gruner, M. Wuttig, P. Entel, Phys. Rev. B 82, 214421 (2010)ADSCrossRefGoogle Scholar
  29. 29.
    J.-G. Zhu, C. Park, Mater. Today 9, 36 (2006)CrossRefGoogle Scholar
  30. 30.
    M. Kallmayer et al., Appl. Phys. Lett. 91, 192501 (2007)ADSCrossRefGoogle Scholar
  31. 31.
    J. Schmalhorst, A. Thomas, G. Reiss, X. Kou, E. Arenholz, J. Appl. Phys. 102, 053907 (2007)ADSCrossRefGoogle Scholar
  32. 32.
    A. Vedyayev, N. Ryzhanova, R. Vlutters, B. Dieny, Europhys. Lett. 46, 808 (1999)ADSCrossRefGoogle Scholar
  33. 33.
    C. Gusenbauer, T. Ashraf, J. Stangl, G. Hesser, T. Plach, A. Meingast, G. Kothleitner, R. Koch, Phys. Rev. B 83, 035319 (2011)ADSCrossRefGoogle Scholar
  34. 34.
    X.W. Zhou, H.N. Wagley, Phys. Rev. B 71, 054418 (2005)ADSCrossRefGoogle Scholar
  35. 35.
    M. Julliere, Phys. Lett. 54, 225 (1975)CrossRefGoogle Scholar
  36. 36.
    T. Miyazaki, N. Tezuka, J. Magn. Magn. Mater. 139, 231 (1995)ADSGoogle Scholar
  37. 37.
    J.P. Velev, P.A. Dowben, E. Tsymbal, S.J. Jenkins, A.N. Caruso, Surf. Sci. Rep. 63, 400 (2008)ADSCrossRefGoogle Scholar
  38. 38.
    M. Hattori, Y. Sakuraba, M. Oogane, Y. Ando, T. Miyazaki, Appl. Phys. Express 1, 021301 (2008)ADSCrossRefGoogle Scholar
  39. 39.
    N. Tezuka, N. Ikeda, F. Mitsuhashi, S. Sugimoto, Appl. Phys. Lett. 94, 162504 (2009)ADSCrossRefGoogle Scholar
  40. 40.
    S. Trudel, O. Gaier, J. Hamrle, B. Hillebrands, J. Phys. D: Appl. Phys. 43, 193001 (2010)ADSCrossRefGoogle Scholar
  41. 41.
    K.J. Buschow (ed.), Handbook of Magnetic Materials, vol. 17 (North-Holland, Amsterdam, 2007)Google Scholar
  42. 42.
    M. Oogane, Y. Sakuraba, J. Nakata, H. Kubota, Y. Ando, A. Sakuma, T. Miyazaki, J. Phys. D: Appl. Phys. 39, 834 (2006)ADSCrossRefGoogle Scholar
  43. 43.
    P. Pörsch, M. Kallmayer, T. Eichhorn, G. Jakob, H.J. Elmers, C.A. Jenkins, C. Felser, R. Ramesh, M. Huth, Appl. Phys. Lett. 93, 022501 (2008)ADSCrossRefGoogle Scholar
  44. 44.
    F. Heusler, Verh. Deutsch. Phys. Ges. 5, 219 (1903)Google Scholar
  45. 45.
    J. Kübler, Phys. Rev. B 28, 1745 (1983)ADSCrossRefGoogle Scholar
  46. 46.
    D. Erb, G. Nowak, K. Westerholt, H. Zabel, J. Phys. D: Appl. Phys. 43, 285001 (2010)CrossRefGoogle Scholar
  47. 47.
    L. Krusin-Elbaum, A.P. Malozemoff, R.C. Taylor, Phys. Rev. B 27, 562 (1983)ADSCrossRefGoogle Scholar
  48. 48.
    P.J. Webster, J. Phys. Chem. Solids 32, 1221 (1983)ADSCrossRefGoogle Scholar
  49. 49.
    U. Geiersbach, A. Bergmann, K. Westerholt, J. Magn. Magn. Mater. 240, 546 (2002)ADSCrossRefGoogle Scholar
  50. 50.
    B. Krumme, H. Herper, D. Erb, C. Weis, C. Antoniak, A. Warland, K. Westerholt, P. Entel, H. Wende, J. Phys. D: Appl. Phys. 44, 415004 (2011)CrossRefGoogle Scholar
  51. 51.
    H. Wende, Rep. Prog. Phys. 67, 2105 (2004)ADSCrossRefGoogle Scholar
  52. 52.
    H. Dürr, G. van der Laan, D. Spanke, F. Hillebrecht, N. Brookes, Phys. Rev. B 56, 8156 (1997)ADSCrossRefGoogle Scholar
  53. 53.
    O. Šipr, J. Minár, A. Scherz, H. Wende, H. Ebert, Phys. Rev. B 84, 115102 (2011)ADSCrossRefGoogle Scholar
  54. 54.
    H. Landolt, R. Börnstein (eds.), New Series Landolt-Börnstein, vol. III/19c (Springer, Berlin, 1988)Google Scholar
  55. 55.
    A. Ionescu et al., Phys. Rev. B 71, 094401 (2005)ADSCrossRefGoogle Scholar
  56. 56.
    C. Antoniak, H.C. Herper, Y.N. Zhang, A. Warland, T. Kachel, F. Stromberg, B. Krumme, C. Weis, K. Fauth, W. Keune, P. Entel, R.Q. Wu, J. Lindner, H. Wende, Phys. Rev. B 85, 214432 (2012)Google Scholar
  57. 57.
    S.I. Makarov, B. Krumme, F. Stromberg, C. Weis, W. Keune, H. Wende, Appl. Phys. Lett. 99, 141910 (2011)ADSCrossRefGoogle Scholar
  58. 58.
    M. Arita, S. Nasu, F. Fujita, Trans. Jpn. Inst. Met. 26, 710 (1985)Google Scholar
  59. 59.
    V. Ko, J. Qiu, P. Luo, G.C. Han, Y.P. Feng, J. Appl. Phys. 109, 07B103 (2011)Google Scholar
  60. 60.
    H.C. Herper, B. Krumme, D. Ebke, C. Antoniak, C. Weis, A. Warland, A. Hütten, H. Wende, P. Entel, J. Appl. Phys. 109, 07E128 (2011)Google Scholar
  61. 61.
    V. Jung, G.H. Fecher, B. Balke, V. Ksenofontov, C. Felser, J. Phys. D: Appl. Phys. 42, 084007 (2009)ADSCrossRefGoogle Scholar
  62. 62.
    L. Hongzhi, Z. Zhiyong, M. Li, X. Shifeng, L. Heyan, Q. Jingping, L. Yangxian, W. Guangheng, J. Phys. D: Appl. Phys. 40, 7121 (2007)CrossRefGoogle Scholar
  63. 63.
    J. Kübler, G. Fecher, C. Felser, Phys. Rev. B 76, 024414 (2007)ADSCrossRefGoogle Scholar
  64. 64.
    S. Wurmehl, G.H. Fecher, H.C. Kandpal, V. Ksenofontov, C. Felser, H.-J. Lin, J. Morais, Phys. Rev. B 72, 184434 (2005)ADSCrossRefGoogle Scholar
  65. 65.
    H. Ebert et al., The Munich SPR-KKR package, version 3.6, http://olymp.cup.uni-muenchen.de/ak/ebert/SPRKKR
  66. 66.
    H. Ebert, Fully relativistic band structure calculations for magnetic solids—formalism and application, in Electronic Structure and Physical Properties of Solids, Lecture Notes in Physics, vol. 535, ed. by H. Dreyssé (Springer, Berlin, 2000), p. 191Google Scholar
  67. 67.
    H. Ebert, Rep. Prog. Phys. 59, 1665 (1996)ADSCrossRefGoogle Scholar
  68. 68.
    H.C. Herper, to be publishedGoogle Scholar
  69. 69.
    A.I. Liechtenstein, V.I. Anisimov, J. Zaanen, Phys. Rev. B 52, R5467 (1995)ADSCrossRefGoogle Scholar
  70. 70.
    S.L. Dudarev, G.A. Botton, S.Y. Savrasov, C.J. Humphreys, A.P. Sutton, Phys. Rev. B 57, 1505 (1998)ADSCrossRefGoogle Scholar
  71. 71.
    J. Thoene, S. Chadov, G. Fecher, C. Felser, J. Kübler, J. Phys. D: Appl. Phys. 42, 084013 (2009)ADSCrossRefGoogle Scholar
  72. 72.
    Y. Nakamura, Landolt-Börnstein, New Series, vol. III/19c (Springer, Berlin, 1988)Google Scholar
  73. 73.
    P.W. Anderson, in Solid State Physics, Chap. Theory of magnetic exchange interactions: exchange in insulators and, semiconductors, vol. 14, ed. by F. Seitz, D. Turnbull (Academic, New York, 1993), p. 99Google Scholar
  74. 74.
    G. Kresse, J. Furthmüller, Comput. Mater. Sci. 6, 15 (1996)CrossRefGoogle Scholar
  75. 75.
    P. Entel, A. Dannenberg, M. Siewert, H.C. Herper, M.E. Gruner, V.D. Buchelnikov, V.A. Chernenko, Mater. Sci. Forum 684, 1 (2011)CrossRefGoogle Scholar
  76. 76.
    X.-Q. Chen, R. Podloucky, P. Rogl, J. Appl. Phys. 100, 113901 (2006)ADSCrossRefGoogle Scholar
  77. 77.
    J. Herfort, H.-P. Schönherr, A. Kawaharazuka, M. Ramsteiner, K.H. Ploog, J. Cryst. Growth 278, 666 (2005)ADSCrossRefGoogle Scholar
  78. 78.
    V.P. LaBella, M.R. Krause, Z. Ding, P.M. Thibado, Surf. Sci. Rep. 60, 1 (2005)ADSCrossRefGoogle Scholar
  79. 79.
    Q. Xue, T. Hashizume, J.M. Zhou, T. Sakata, T. Ohno, T. Sakurai, Phys. Rev. Lett. 74, 3177 (1995)ADSCrossRefGoogle Scholar
  80. 80.
    R.A. Gordon, E.D. Crozier, D.-T. Jiang, T.L. Monchesky, B. Heinrich, Phys. Rev. B 62, 2151 (2005)ADSCrossRefGoogle Scholar
  81. 81.
    S. Mirbt, B. Sanyal, C. Isheden, B. Johansson, Phys. Rev. B 67, 155421 (2003)ADSCrossRefGoogle Scholar
  82. 82.
    H.C. Herper, P. Entel, Philos. Mag. 88, 2699 (2008)ADSCrossRefGoogle Scholar
  83. 83.
    J. Herfort, H.-P. Schönherr, K. Ploog, Appl. Phys. Lett. 83, 3912 (2003)ADSCrossRefGoogle Scholar
  84. 84.
    L. Wining, M. Wenderoth, J. Homoth, A. Siewers, R. Ulbrich, Appl. Phys. Lett. 92, 193102 (2008)ADSCrossRefGoogle Scholar
  85. 85.
    A. Grünebohm, H.C. Herper, P. Entel, Phys. Rev. B 80, 064417 (2009)ADSCrossRefGoogle Scholar
  86. 86.
    H. Wende, unpublishedGoogle Scholar
  87. 87.
    A. Grünebohm, M. Siewert, H.C. Herper, M.E. Gruner, P. Entel, J. Phys.: Conf. Ser. 200, 072038 (2009)Google Scholar
  88. 88.
    W.C. Lim, G.M. Choi, T.D. Lee, S. Seo, IEEE 44, 2595 (2008)Google Scholar
  89. 89.
    S. Hakamata, T. Ishikawa, T. Marukame, K. Matsuda, T. Uemura, M. Arita, M. Yamamoto, J. Appl. Phys. 101, 09J513 (2007)Google Scholar
  90. 90.
    D.M. Roessler, W.C. Walker, Phys. Rev. 159, 733 (1967)ADSCrossRefGoogle Scholar
  91. 91.
    O. Taurian, M. Springborg, N. Christensen, Sol. States Commun. 55, 351 (1985)ADSCrossRefGoogle Scholar
  92. 92.
    D. Kmiec, B. Sepiol, M. Sladecek, M. Rennhofer, S. Stankov, G. Vogl, B. Laenens, J. Meersschaut, T. Slezak, M. Zajkac, Phys. Rev. B 75, 054306 (2007)Google Scholar
  93. 93.
    K. Zakeri et al., Phys. Rev. B 76, 214421 (2007)ADSCrossRefGoogle Scholar
  94. 94.
    H. Schneider, G. Jakob, M. Kallmayer, H. Elmers, B. Balke, S. Wurmehl, C. Felser, M. Aeschlimann, H. Adrian, Phys. Rev. B 74, 174426 (2006)ADSCrossRefGoogle Scholar
  95. 95.
    I. Galanakis, P. Dederichs (eds.), Half-Metallic Alloys, Lecture Notes in Physics (Springer, Berlin, 2005)Google Scholar
  96. 96.
    G.H. Fecher, H.C. Kandpal, S. Wurmehl, C. Felser, G. Schönhense, J. Appl. Phys. 99, 08J106 (2006)Google Scholar
  97. 97.
    S. Picozzi, A. Continenza, A.J. Freeman, Phys. Rev. B 69, 094423 (2004)ADSCrossRefGoogle Scholar
  98. 98.
    B. Hülsen, M. Scheffler, P. Kratzer, Phys. Rev. B 79, 094407 (2009)ADSCrossRefGoogle Scholar
  99. 99.
    T. Ishikawa, H. Liu, T. Tairo, K.-I. Matsuda, T. Uemura, M. Yamamoto, Appl. Phys. Lett. 95, 232512 (2009)ADSCrossRefGoogle Scholar
  100. 100.
    T. Ishikawa, T. Marukame, H. Kijima, K.-I. Matsuda, T. Uemura, M. Arita, M. Yamamoto, Appl. Phys. Lett. 89, 192505 (2006)ADSCrossRefGoogle Scholar
  101. 101.
    K. Reuter, C. Stampfl, M. Scheffler, in Handbook of Materials Modeling, Chap. Ab initio thermodynamics and statistical mechanics of surface properties and functions, edited by S. Yip (Springer, Berlin, 2005), p. 149Google Scholar
  102. 102.
    B. Hülsen, M. Scheffler, P. Kratzer, Phys. Rev. Lett. 103, 046802 (2009)ADSCrossRefGoogle Scholar
  103. 103.
    S.J. Hashemifar, P. Kratzer, M. Scheffler, Phys. Rev. Lett. 94, 096402 (2005)ADSCrossRefGoogle Scholar
  104. 104.
    M. Kallmayer, H. Schneider, G. Jakob, H.J. Elmers, B. Balke, S. Cramm, J. Phys. D: Appl. Phys. 40, 1552 (2007)ADSCrossRefGoogle Scholar
  105. 105.
    M. Jourdan, E.A. Jorge, C. Herbort, M. Kallmayer, P. Klaer, H.J. Elmers, Appl. Phys. Lett. 95, 172504 (2009)ADSCrossRefGoogle Scholar
  106. 106.
    J. Grabis, A. Bergmann, A. Nefedov, K. Westerholt, H. Zabel, Phys. Rev. B 72, 024438 (2005)ADSCrossRefGoogle Scholar
  107. 107.
    M. Vadalá, A. Nefedov, M. Wolff, K.N. Zhernenkov, K. Westerholt, H. Zabel, J. Phys. D: Appl. Phys. 40, 1289 (2007)ADSCrossRefGoogle Scholar
  108. 108.
    A. Bergmann, J. Grabis, A. Nefedov, K. Westerholt, H. Zabel, J. Phys. D: Appl. Phys. 39, 842 (2006)ADSCrossRefGoogle Scholar
  109. 109.
    P. Mavropoulos, M. Ležaić, S. Blügel, Phys. Rev. B 72, 174428 (2005)ADSCrossRefGoogle Scholar
  110. 110.
    I. Mertig, Rep. Prog. Phys. 62, 237 (1999)ADSCrossRefGoogle Scholar
  111. 111.
    H.C. Herper, P. Weinberger, L. Szunyogh, C. Sommers, Phys. Rev. B 66, 064426 (2002)ADSCrossRefGoogle Scholar
  112. 112.
    J.S. Moodera, J. Nassar, G. Mathon, Annu. Rev. Mater. Sci. 29, 381 (1999)ADSCrossRefGoogle Scholar
  113. 113.
    J. Mathon, A. Umerski, Phys. Rev. B 63, 220403 (2001)ADSCrossRefGoogle Scholar
  114. 114.
    R. Landauer, IBM Res. J. Dev. 1, 223 (1957)MathSciNetCrossRefGoogle Scholar
  115. 115.
    W.H. Butler, X.-G. Zhang, T. Schulthess, J.M. MacLaren, Phys. Rev. B 63, 054416 (2001)ADSCrossRefGoogle Scholar
  116. 116.
    M. Oogane, S. Mizukami, Trans. R. Soc. 369, 3037 (2011)ADSCrossRefGoogle Scholar
  117. 117.
    Y. Sakuraba, M. Hattori, M. Oogane, Y. Ando, H. Kato, A. Sakuma, T. Miyazaki, H. Kubota, Appl. Phys. Lett. 88, 192508 (2006)ADSCrossRefGoogle Scholar
  118. 118.
    E. Ozawa, S. Tsunegi, M. Oogane, H. Naganum, Y. Ando, J. Phys, Conf. Ser. 266, 012104 (2011)ADSCrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Heike C. Herper
    • 1
  • Peter Kratzer
    • 1
  • Heiko Wende
    • 1
  • Bernhard Krumme
    • 1
  • Kurt Westerholt
    • 2
  • Peter Entel
    • 1
  1. 1.Faculty of PhysicsUniversity of Duisburg-EssenDuisburgGermany
  2. 2.Institute of PhysicsRuhr-University of BochumBochumGermany

Personalised recommendations