In situ grazing-incidence small-angle X-ray scattering observation of block-copolymer templated formation of magnetic nanodot arrays and their magnetic properties


The fabrication of bit-patterned media (BPM) is crucial for new types of hard disk drives. The development of methods for the production of BPM is progressing rapidly. Conventional lithography reaches the limit regarding lateral resolution, and new routes are needed. In this study, we mainly focus on the dependence of the size and shape of magnetic nanodots on the Ar+-ion etching duration, using silica dots as masks. Two-dimensional (2D) arrays of magnetic nanostructures are created using silica-filled diblock-copolymer micelles as templates. After the self-assembly of the micelles into 2D hexagonal arrays, the polymer shell is removed, and the SiO2 cores are utilized to transform the morphology into a (Co/Pt)2-multilayer via ion etching under normal incidence. The number of preparation steps is kept as low as possible to simplify the formation of the nanostructure arrays. High-resolution in situ grazing-incidence small-angle X-ray scattering (GISAXS) investigations are performed during the Ar+-ion etching to monitor and control the fabrication process. The in situ investigation provides information on how the etching conditions can be improved for further ex situ experiments. The GISAXS patterns are compared with simulations. We observe that the dots change in shape from cylindrical to conical during the etching process. The magnetic behavior is studied by utilizing the magneto-optic Kerr effect. The Co/Pt dots exhibit different magnetic behaviors depending on their size, interparticle distance, and etching time. They show ferromagnetism with an easy axis of magnetization perpendicular to the film. A systematic dependence of the coercivity on the dot size is observed.

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  1. [1]

    Lille, J.; Patel, K.; Ruiz, R.; Wu, T. W.; Gao, H.; Wan, L.; Zeltzer, G.; Dobisz, E.; Albrecht, T. R. Imprint lithography template technology for bit patterned media (BPM). In Proceedings of the SPIE 8166, Photomask Technology 2011, Monterey, CA,USA, 2011.

    Google Scholar 

  2. [2]

    Shaw, J. M.; Rippard, W. H.; Russek, S. E.; Reith, T.; Falco, C. M. Origins of switching field distributions in perpendicular magnetic nanodot arrays. J. Appl. Phys. 2007, 101, 023909.

    Article  Google Scholar 

  3. [3]

    Hamley, I. W. The Physics of Block Copolymers; Oxford University Press: Oxford, UK, 1998.

    Google Scholar 

  4. [4]

    Leibler, L. Theory of microphase separation in block copolymers. Macromolecules 1980, 13, 1602–1617.

    Article  Google Scholar 

  5. [5]

    Fasolka, M. J.; Mayes, A. M. Block copolymer thin films: Physics and applications. Annu. Rev. Mater. Res. 2001, 31, 323–355.

    Article  Google Scholar 

  6. [6]

    Krausch, G.; Magerle, R. Nanostructured thin films via self-assembly of block copolymers. Adv. Mater. 2002, 14, 1579–1583.

    Article  Google Scholar 

  7. [7]

    Böker, A.; Müller, A. H. E.; Krausch, G. Nanoscopic surface patterns from functional ABC triblock copolymers. Macromolecules 2001, 34, 7477–7488.

    Article  Google Scholar 

  8. [8]

    Knoll, A.; Tsarkova, L.; Krausch, G. Nanoscaling of microdomain spacings in thin films of cylinder-forming block copolymers. Nano Lett. 2007, 7, 843–846.

    Article  Google Scholar 

  9. [9]

    Tsarkova, L.; Knoll, A.; Krausch, G.; Magerle, R. Substrateinduced phase transitions in thin films of cylinder-forming diblock copolymer melts. Macromolecules 2006, 39, 3608–3615.

    Article  Google Scholar 

  10. [10]

    Park, M.; Harrison, C.; Chaikin, P. M.; Register, R. A.; Adamson, D. H. Block copolymer lithography: Periodic arrays of ~1011 holes in 1 square centimeter. Science 1997, 276, 1401–1404.

    Article  Google Scholar 

  11. [11]

    Li, R. R.; Dapkus, P. D.; Thomson, M. E.; Jeong, W. G.; Harrison, C.; Chaikin, P. M.; Register, R. A.; Adamson, D. H. Dense arrays of ordered GaAs nanostructures by selective area growth on substrates patterned by block copolymer lithography. Appl. Phys. Lett. 2000, 76, 1689–1691.

    Article  Google Scholar 

  12. [12]

    Thurn-Albrecht, T.; Schotter, J.; Kästle, G. A.; Emley, N.; Shibauchi, T.; Krusin-Elbaum, L.; Guarini, K.; Black, C. T.; Tuominen, M. T.; Russell, T. P. Ultrahigh-density nanowire arrays grown in self-assembled diblock copolymer templates. Science 2000, 290, 2126–2129.

    Article  Google Scholar 

  13. [13]

    Kim, H.-C.; Jia, X.; Stafford, C. M.; Kim, D. H.; McCarthy, T. J.; Tuominen, M.; Hawker, C. J.; Russell, T. P. A route to nanoscopic SiO2 posts via block copolymer templates. Adv. Mater. 2001, 13, 795–797.

    Article  Google Scholar 

  14. [14]

    Melde, B. J.; Burkett, S. L.; Xu, T.; Goldbach, J. T.; Russell, T. P.; Hawker, C. J. Silica nanostructures templated by oriented block copolymer thin films using pore-filling and selective-mineralization routes. Chem. Mater. 2005, 17, 4743–4749.

    Article  Google Scholar 

  15. [15]

    Jung, J.-M.; Kwon, K. Y.; Ha, T.-H.; Chung, B. H.; Jung, H.-T. Gold-conjugated protein nanoarrays through blockcopolymer lithography: From fabrication to biosensor design. Small 2006, 2, 1010–1015.

    Article  Google Scholar 

  16. [16]

    Lee, D. H.; Shin, D. O.; Lee, W. J.; Kim, S. O. Hierarchically organized carbon nanotube arrays from self-assembled block copolymer nanotemplates. Adv. Mater. 2008, 20, 2480–2485.

    Article  Google Scholar 

  17. [17]

    Cheng, J. Y.; Ross, C. A.; Chan, V. Z.-H.; Thomas, E. L.; Lammertink, R. G. H.; Vansco, G. J. Formation of a cobalt magnetic dot array via block copolymer lithography. Adv. Mater. 2001, 13, 1174–1178.

    Article  Google Scholar 

  18. [18]

    Ross, C. A.; Jung, Y. S.; Chuang, V. P.; Ilievski, F.; Yang, J. K. W.; Bita, I.; Thomas, E. L.; Smith, H. I.; Berggren, K. K.; Vansco, G. J. et al. Si-containing block copolymers for self-assembled nanolithography. J. Vac. Sci. Technol. B 2008, 26, 2489–2494.

    Article  Google Scholar 

  19. [19]

    Dong, Q. C.; Li, G. J.; Ho, C.-L.; Faisal, M.; Leung, C.-W.; Pong, P. W.-T.; Liu, K.; Tang, B.-Z.; Manners, I.; Wong, W.-Y. A polyferroplatinyne precursor for the rapid fabrication of L10-FePt-type bit patterned media by nanoimprint lithography. Adv. Mater. 2012, 24, 1034–1040.

    Article  Google Scholar 

  20. [20]

    Dong, Q. C.; Li, G. J.; Ho, C.-L.; Leung, C.-W.; Pong, P. W.-T.; Manners, I.; Wong, W.-Y. Facile generation of L10-FePt nanodot arrays from a nanopatterned metallopolymer blend of iron and platinum homopolymers. Adv. Funct. Mater. 2014, 24, 857–862.

    Article  Google Scholar 

  21. [21]

    Dong, Q. C.; Li, G. J.; Wang, H.; Pong, P. W.-T.; Leung, C.-W.; Manners, I.; Ho, C.-L.; Wong, W.-Y. Investigation of pyrolysis temperature in the one-step synthesis of L10 FePt nanoparticles from a FePt-containing metallopolymer. J. Mater. Chem. C 2015, 3, 734–741.

    Article  Google Scholar 

  22. [22]

    Dong, Q. C.; Qu, W. S.; Liang, W. Q.; Guo, K. P.; Xue, H. B.; Guo, Y. Y.; Meng, Z. G.; Ho, C.-L.; Leung, C.-W.; Wong, W.-Y. Metallopolymer precursors to L10-CoPt nanoparticles: Synthesis, characterization, nanopatterning and potential application. Nanoscale 2016, 8, 7068–7074.

    Article  Google Scholar 

  23. [23]

    Lodge, T. P.; Pudil, B.; Hanley, K. J. The full phase behavior for block copolymers in solvents of varying selectivity. Macromolecules 2002, 35, 4707–4717.

    Article  Google Scholar 

  24. [24]

    Lai, C.; Russel, W. B.; Register, R. A. Phase behavior of styrene-isoprene diblock copolymers in strongly selective solvents. Macromolecules 2002, 35, 841–849.

    Article  Google Scholar 

  25. [25]

    Lee, S.; Bluemle, M. J.; Bates, F. S. Discovery of a Frank-Kaspar s phase in sphere-forming block copolymer melts. Science 2010, 330, 349–353.

    Article  Google Scholar 

  26. [26]

    Bennett, T. M.; Jack, K. S.; Thurecht, K. J.; Blakey, I. Perturbation of the experimental phase diagram of a diblock copolymer by blending with an ionic liquid. Macromolecules 2016, 49, 205–214.

    Article  Google Scholar 

  27. [27]

    Li, Z.; Zhao, W.; Liu, Y.; Rafailovich, M. H.; Sokolov, J.; Khougaz, K.; Eisenberg, A.; Lennox, R. B.; Krausch, G. Self-ordering of diblock copolymers from solution. J. Am. Chem. Soc. 1996, 118, 10892–10893.

    Article  Google Scholar 

  28. [28]

    Meiners, J. C.; Quintel-Ritzi, A.; Mlynek, J.; Elbs, H.; Krausch, G. Adsorption of block-copolymer micelles from a selective solvent. Macromolecules 1997, 30, 4945–4951.

    Article  Google Scholar 

  29. [29]

    Spatz, J. P.; Sheiko, S.; Möller, M. Ion-stabilized block copolymer micelles: Film formation and intermicellar interaction. Macromolecules 1996, 29, 3220–3226.

    Article  Google Scholar 

  30. [30]

    Spatz, J. P.; Herzog, T.; Mößmer, S.; Ziemann, P.; Möller, M. Micellar inorganic-polymer hybrid systems—A tool for nanolithography. Adv. Mater. 1999, 11, 149–153.

    Article  Google Scholar 

  31. [31]

    Spatz, J. P.; Mößmer, S.; Hartmann, C.; Möller, M. Ordered deposition of inorganic clusters from micellar block copolymer films. Langmuir 2000, 16, 407–415.

    Article  Google Scholar 

  32. [32]

    Haupt, M.; Miller, S.; Glass, R.; Arnold, M.; Sauer, R.; Thonke, K.; Möller, M.; Spatz, J. P. Nanoporous gold films created using templates formed from self-assembled structures of inorganic-block copolymer micelles. Adv. Mater. 2003, 15, 829–831.

    Article  Google Scholar 

  33. [33]

    Bhaviripudi, S.; Reina, A.; Qi, J. F.; Kong, J.; Belcher, A. M. Block-copolymer assisted synthesis of arrays of metal nanoparticles and their catalytic activities for the growth of SWNTs. Nanotechnology 2006, 17, 5080–5086.

    Article  Google Scholar 

  34. [34]

    Shan, L. C.; Punniyakoti, S.; van Bael, M. J.; Temst, K.; van Bael, M. K.; Ke, X. X.; Bals, S.; van Tendeloo, G.; D’Olieslaeger, M.; Wagner, P. et al. Homopolymers as nanocarriers for the loading of block copolymer micelles with metal salts: A facile way to large-scale ordered arrays of transition-metal nanoparticles. J. Mater. Chem. C 2014, 2, 701–707.

    Article  Google Scholar 

  35. [35]

    Aizawa, M.; Buriak, J. M. Block copolymer-templated chemistry on Si, Ge, InP, and GaAs surfaces. J. Am. Chem. Soc. 2005, 127, 8932–8933.

    Article  Google Scholar 

  36. [36]

    Sun, Z.; Wolkenhauer, M.; Bumbu, G.-G.; Kim, D. H.; Gutmann, J. S. GISAXS investigation of TiO2 nanoparticles in PS-b-PEO block-copolymer films. Phys. B 2005, 357, 141–143.

    Article  Google Scholar 

  37. [37]

    Kim, D. H.; Sun, Z.; Russell, T. P.; Knoll, W.; Gutmann, J. S. Organic-inorganic nanohybridization by block copolymer thin films. Adv. Funct. Mater. 2005, 15, 1160–1164.

    Article  Google Scholar 

  38. [38]

    Li, X.; Lau, K. H. A.; Kim, D. H.; Knoll, W. High-density arrays of titania nanoparticles using monolayer micellar films of diblock copolymers as templates. Langmuir 2005, 21, 5212–5217.

    Article  Google Scholar 

  39. [39]

    Sun, Z. C.; Kim, D. H.; Wolkenhauer, M.; Bumbu, G.-G.; Knoll, W.; Gutmann, J. S. Synthesis and photoluminescence of titania nanoparticle arrays templated by block-copolymer thin films. ChemPhysChem 2006, 7, 370–378.

    Article  Google Scholar 

  40. [40]

    Bennett, R. D.; Xiong, G. Y.; Ren, Z. F.; Cohen, R. E. Using block copolymer micellar thin films as templates for the production of catalysts for carbon nanotube growth. Chem. Mater. 2004, 16, 5589–5595.

    Article  Google Scholar 

  41. [41]

    Loginova, T. P.; Kabachi, Y. A.; Sidorow, S. N.; Zhirov, D. N.; Valetsky, P. M.; Ezernitskaya, M. G.; Dybrovina, L. V.; Bragina, T. P.; Lependina, O. L.; Stein, B. et al. Molybdenum sulfide nanoparticles in block copolymer micelles: Synthesis and tribological properties. Chem. Mater. 2004, 16, 2369–2378.

    Article  Google Scholar 

  42. [42]

    Wiedwald, U.; Han, L. Y.; Biskupek, J.; Kaiser, U.; Ziemann, P. Preparation and characterization of supported magnetic nanoparticles prepared by reverse micelles. Beilstein J. Nanotechnol. 2010, 1, 24–27.

    Article  Google Scholar 

  43. [43]

    Aizawa, M.; Buriak, J. M. Block copolymer templated chemistry for the formation of metallic nanoparticle arrays on semiconductor surfaces. Chem. Mater. 2007, 19, 5090–5101.

    Article  Google Scholar 

  44. [44]

    Sakar, K.; Schaffer, C. J.; Mosegui Gonzales, D.; Naumann, A.; Perlich, J.; Mueller-Buschbaum, P. Tuning pore size of ZnO nano-grids via time-dependent solvent annealing. J. Mater. Chem. A 2014, 2, 6945–6951.

    Article  Google Scholar 

  45. [45]

    Schwartzkopf, M.; Santoro, G.; Brett, C. J.; Rothkirch, A.; Polonskyi, O.; Hinz, A.; Metwalli, E.; Yao, Y.; Strunskus, T.; Faupel, F. et al. Real-time monitoring of morphology and optical properties during sputter deposition for tailoring metal-polymer interfaces. ACS Appl. Mater. Interfaces 2015, 7, 13547–13556.

    Article  Google Scholar 

  46. [46]

    Schwartzkopf, M.; Buffet, A.; Körstgens, V.; Metwalli, E.; Schlage, K.; Benecke, G.; Perlich, J.; Rawolle, M.; Rothkirch, A.; Heidmann, B. et al. From atoms to layers: In situ gold cluster growth kinetics during sputter deposition. Nanoscale 2013, 5, 5053–5062.

    Article  Google Scholar 

  47. [47]

    Frömsdorf, A.; Kornowski, A.; Pütter, S.; Stillrich, H.; Lee, L.-T. Highly ordered nanostructured surfaces obtained with silica-filled diblock-copolymer micelles as templates. Small 2007, 3, 880–889.

    Article  Google Scholar 

  48. [48]

    Pütter, S.; Stillrich, H.; Frömsdorf, A.; Menk, C.; Frömter, R.; Förster, S.; Oepen, H. P. Magnetic antidot arrays using SiO2 filled diblock copolymer micelles as ion etching mask. J. Magn. Magn. Mater. 2007, 316, e40–e43.

    Article  Google Scholar 

  49. [49]

    Stillrich, H.; Frö msdorf, A.; Pü tter, S.; Förster, S.; Oepen, H. P. Sub-20 nm magnetic dots with perpendicular magnetic anisotropy. Adv. Funct. Mater. 2008, 18, 76–81.

    Article  Google Scholar 

  50. [50]

    Neumann, A.; Franz, N.; Hoffmann, G.; Meyer, A.; Oepen, H. P. Fabrication of magnetic Co/Pt nanodots utilizing filled diblock copolymers. Open Surf. Sci. J. 2012, 4, 55–64.

    Article  Google Scholar 

  51. [51]

    Neumann, A.; Thönnißen, C.; Frauen, A.; Heße, S.; Meyer, A.; Oepen, H. P. Probing the magnetic behavior of single nanodots. Nano Lett. 2013, 13, 2199–2203.

    Article  Google Scholar 

  52. [52]

    Neumann, A.; Altwein, D.; Thönnißen, C.; Wieser, R.; Berger, A.; Meyer, A.; Vedmedenko, E.; Oepen, H. P. Influence of long-range interactions on the switching behavior of particles in an array of ferromagnetic nanostructures. New J. Phys. 2014, 16, 083012.

    Article  Google Scholar 

  53. [53]

    Wellhöfer, M.; Weiß enborn, M.; Anton, R.; Pütter, S.; Oepen, H. P. Morphology and magnetic properties of ECR ion beam sputtered Co/Pt films. J. Magn. Magn. Mater. 2005, 292, 345–358.

    Article  Google Scholar 

  54. [54]

    Stillrich, H.; Menk, C.; Frömter, R.; Oepen, H. P. Magnetic anisotropy and spin reorientation in Co/Pt multilayers: Influence of preparation. J. Magn. Magn. Mater. 2010, 322, 1353–1356.

    Article  Google Scholar 

  55. [55]

    Förster, S.; Antonietti, M. Amphiphilic block copolymers in structure-controlled nanomaterial hybrids. Adv. Mater. 1998, 10, 195–217.

    Article  Google Scholar 

  56. [56]

    Frömsdorf, A.; Capek, R.; Roth, S. V. µ-GISAXS experiment and simulation of a highly ordered model monolayer of PMMA-beads. J. Chem. Phys. B 2006, 110, 15166–15171.

    Article  Google Scholar 

  57. [57]

    Renaud, G.; Lazzari, R.; Leroy, F. Probing surface and interface morphology with grazing incidence small angle X-ray scattering. Surf. Sci. Rep. 2009, 64, 255–380.

    Article  Google Scholar 

  58. [58]

    Hexemer, A.; Müller-Buschbaum, P. Advanced grazingincidence techniques for modern soft-matter materials analysis. IUCrJ 2015, 2, 106–125.

    Article  Google Scholar 

  59. [59]

    Lazzari, R. IsGISAXS: A program for grazing-incidence small-angle X-ray scattering analysis of supported islands. J. Appl. Cryst. 2002, 35, 406–421.

    Article  Google Scholar 

  60. [60]

    Sharrock, M.; McKinney, J. Kinetic effects in coercivity measurements. IEEE Trans. Magn. 1981, 17, 3020–3022.

    Article  Google Scholar 

  61. [61]

    Sharrock, M. P. Time-dependent magnetic phenomena and particle-size effects in recording media. IEEE Trans. Magn. 1990, 26, 193–197.

    Article  Google Scholar 

  62. [62]

    Kneller, E.; Wolff, M. Anomalous superparamagnetism and interface effect. J. Appl. Phys. 1966, 37, 1350–1352.

    Article  Google Scholar 

  63. [63]

    Skomski, R. Nanomagnetics. J. Phys.: Condens. Matter 2003, 15, R841–R896.

    Google Scholar 

  64. [64]

    Millev, Y. T.; Vedmedenko, E.; Oepen, H. P. Dipolar magnetic anisotropy energy of laterally confined ultrathin ferromagnets: Multiplicative separation of discrete and continuum contributions. J. Phys. D.: Appl. Phys. 2003, 36, 2945–2949.

    Article  Google Scholar 

  65. [65]

    Beleggia, M.; de Graef, M.; Millev, Y. T. The equivalent ellipsoid of a magnetized body. J. Phys. D.: Appl. Phys. 2006, 39, 891–899.

    Article  Google Scholar 

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This research was supported by the SFB 668 of the Deutsche Forschungsgemeinschaft and by the University of Hamburg. The authors thank S.V. Roth and the HASYLAB staff for the support at the beamline BW4 and the ESRF staff for their support during beamtime at ID01. We thank A. Kornowski for the helpful advices about the SEM analysis.

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Meyer, A., Franz, N., Oepen, H.P. et al. In situ grazing-incidence small-angle X-ray scattering observation of block-copolymer templated formation of magnetic nanodot arrays and their magnetic properties. Nano Res. 10, 456–471 (2017).

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  • poly(styrene)-b-poly(vinyl pyridine)
  • argon ion etching
  • self-assembly
  • grazing-incidence small-angle X-ray scattering (GISAXS) simulation
  • magnetic nanodot coercivity