Hard Magnetic Materials for MEMS Applications

  • Nora M. Dempsey


Micro-magnets of thickness in the range 1−500 μm have many potential applications in micro-electro-mechanical-systems (MEMS) because of favorable downscaling laws and their unique ability to produce long range bi-directional forces. The advantages and disadvantages of a number of “top-down” routes, which use bulk processed precursors (magnets or magnetic powders), to produce μ-magnets of thickness in the range 10−500 μm will be discussed. Progress in the fabrication and patterning of thick film magnets (1−100 μm) using “bottom-up” deposition techniques will be reviewed. In particular, recent results concerning high-rate triode sputtering and micro-patterning of high-performance NdFeB and SmCo films will be presented.


High Deposition Rate Soft Magnetic Material Hard Magnetic Material Maximum Energy Product FePt Film 
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.



Some of the results presented here were achieved during the thesis of A. Walther (Institut Néel+CEA Léti + G2Elab) and in the framework of the ANR (French National Research Agency) “Nanomag2” project. They are the fruit of collaboration with a number of colleagues including D. Givord (Institut Néel), O. Cugat, J. Delamare, and G. Reyne (G2Elab), C. Marcoux and B. Desloges (CEA Léti), O. Gutfleisch (IFW Dresden) and R. Grechishkin (Tver State University). N. Kornilov is thanked for many fruitful discussions and his invaluable contribution to setting up the triode sputtering system at Institut Néel.


  1. 1.
    Achotte, N., Gilles, P.-A., Cugat, O., Delamare, J., Gaud, P., Dieppedale, C.: Planar brushless magnetic μ-motors. J. MEMS 15(4), 1001–1014 (2006)Google Scholar
  2. 2.
    Allen, R.P., Dahlgren, S.D., Arrowsmith, H.W., Heinrich, J.P.: Research in the Production of Rare-Earth-Cobalt Permanent Magnet Material by Sputter Deposition. Technical report AFML TR-74–87 (1974)Google Scholar
  3. 3.
    Arnold, D.P., Das, S., Cros, F., Zana, I., Allen, M.G., Lang, J.H.: Magnetic induction machines integrated into bulk-micromachined silicon. J. MEMS 15(2), 406–414 (2006)Google Scholar
  4. 4.
    Berkh, O., Rosenberg, Yu., Shacham-Diamand, Y., Gileadi, E.: Electrodeposited near Equiatomic CoPt thick films. Electrochem. Solid-State Lett. 11(4), D38–D41 (2008)CrossRefGoogle Scholar
  5. 5.
    Bernstein, J., Taylor, W., Brazzle, J.D., Corcoran, C.J., Kirkos, G., Odhner, J.E., Pareek, A., Waelti, M., Zai, M.: Electromagnetically actuated mirror arrays for use in 3D optical switching applications. J. MEMS 13(3), 526–535 (2004)Google Scholar
  6. 6.
    Bowers, B.J., Agashe, J.S., Arnold, D.P.: method to form bonded micromagnets embedded in silicon. Solid-State Sensors, Actuators and Microsystems Conference, 2007. TRANSDUCERS’07, 1585–1588 (2007)Google Scholar
  7. 7.
    Budde T., Gatzen, H.H.: Patterned sputter deposited SmCo-films for MEMS Applications. J. Magn. Magn. Mat. 242–245, 1146–1148 (2002)CrossRefGoogle Scholar
  8. 8.
    Budde T., Gatzen, H.H.: Thin film SmCo magnets for use in electromagnetic microactuators. J. Appl. Phys. 99, 08N304-3 (2006)CrossRefGoogle Scholar
  9. 9.
    Buschbeck, J., Fähler, S., Weisheit, M., Leistner, K., McCord, J., Rellinghaus, B., Schultz, L.: Thermodynamics and kinetics during pulsed laser annealing and patterning of FePt films. J. Appl. Phys. 100, 123901-7 (2006)CrossRefGoogle Scholar
  10. 10.
    Cadieu, F.J.: Permanent magnet thin films: A review of Film Synthesis and Properties. In: Francombe, M., Vossen, J. (eds.) Physics of Thin Films, vol. 16. Academic Press Inc., (1992)Google Scholar
  11. 11.
    Cavallotti, P.L., Lecis, N., Fauser, H., Zielonka, A., Celis, J.P., Wouters, G., Machado da Silva, J., Brochado Oliveira, J.M., Sa, M.A.: Electrodeposition of magnetic multilayers. Surface and Coatings Technology 105, 232–239 (1998)CrossRefGoogle Scholar
  12. 12.
    Chen, C.H., Walmer, M.S., Walmer, M.H., Gong, W., Ma, B.-M.: The relationship of thermal expansion to magnetocrystalline anisotropy, spontaneous magnetization, and Tc for permanent magnets. J. Appl. Phys. 85, 5669–5671 (1999)CrossRefGoogle Scholar
  13. 13.
    Chetouani, H., Haguet, V., Jeandey, C., Pigot, C., Walther, A., Dempsey, N.M., Chatelain, F., Delinchant, B., Reyne, G.: Diamagnetic levitation of beads and cells above permanent magnets. Solid-State Sensors, Actuators and Microsystems Conference, 2007. TRANSDUCERS’07, 715–718 (2007)Google Scholar
  14. 14.
    Cho, H.J., Bhansali, S., Ahn, C.H.: Electroplated thick permanent magnet arrays with controlled direction of magnetization for MEMS application. J. Appl. Phys. 87, 6340–6343 (2000)CrossRefGoogle Scholar
  15. 15.
    Cho H.J., Ahn, C.H.: Microscale resin-bonded permanent magnets for magnetic micro-electro-mechanical systems applications. J. Appl. Phys. 93, 8674–8676 (2003)CrossRefGoogle Scholar
  16. 16.
    Christenson, T.R., Garino, T.J., Venturini, E.L., Berry, D.M.: Application of deep x-ray lithography fabricated rare earth permanent magnets to multipole magnetic microactuators. Electrochem. Soc. Proc. 98–20, 312–323 (1999)Google Scholar
  17. 17.
    Cugat, O., Basrour, S., Divoux, C., Mounaix, P., Reyne, G.: Deformable magnetic mirror for adaptive optics: Technological aspects. Sensors & Actuators A 89, 1–9 (2001)CrossRefGoogle Scholar
  18. 18.
    Cugat, O., Delamare, J., Reyne, G.: Magnetic micro-actuators and systems (MAGMAS). IEEE Trans. Mag. 39, 3607–3612 (2003)CrossRefGoogle Scholar
  19. 19.
    Cui, B.Z., Han, K., Li, D.S., Garmestani, H., Liu, J.P., Dempsey, N.M., Schneider-Muntau, H.J.: Magnetic-field-induced crystallographic texture enhancement in cold-deformed FePt nanostructured magnets. J. Appl. Phys. 100, 013902-4 (2006)CrossRefGoogle Scholar
  20. 20.
    Dempsey, N.M., Walther, A., May, F., Givord, D., Khlopkov, K., Gutfleisch, O.: High performance hard magnetic NdFeB thick films for integration into Micro-Electro-Mechanical Systems. Appl. Phys. Lett. 90, 092509-3 (2007)CrossRefGoogle Scholar
  21. 21.
    Dieppedale, C., Desloges, B., Rostaing, H., Delamare, J., Cugat, O., Meunier-Carus, J.: Magnetic bistable μ-actuator with integrated permanent magnets. Proc. IEEE Sensors 1, 493–496 (2004)CrossRefGoogle Scholar
  22. 22.
    Dutoit, B., Besse, P.A., Blanchard, H., Guérin, L., Popovic, R.S.: High performance micro-machined Sm2Co17 polymer bonded magnets. Sensors Actuators A 77, 178–182 (1999).CrossRefGoogle Scholar
  23. 23.
    Fujita, N., Maeda, S., Yoshida, S., Takase, M., Nakano, M., Fukunaga, H.: Preparation of Co–Pt alloy film magnets by electrodeposition. J. Magn. Magn. Mater. 272–276, e1895–e1897 (2004)CrossRefGoogle Scholar
  24. 24.
    Grechishkin, R., Chigirinsky, S., Gusev, M., Cugat, O., Dempsey, N.M.: Magnetic imaging films. In: G. Asti, L. Pareti, and M. Ghidini (eds.) Magnetic Nanostructures in Modern Technology, pp. 195–224. Springer, Netherlands (2007)Google Scholar
  25. 25.
    Guan S., Nelson, B.J., Vollmers, K.: Electrochemical codeposition of magnetic particle ferromagnetic matrix composites for magnetic MEMS actuator applications. J. Electrochem. Soc. 151(9), C545–C549 (2004)CrossRefGoogle Scholar
  26. 26.
    Guan, S., Nelson, B.J.: Fabrication of hard magnetic microarrays by electroless codeposition for MEMS actuators. Sensors Actuators A 118, 307–312 (2005)CrossRefGoogle Scholar
  27. 27.
    Guan, S., Nelson, B.J.: Electrodeposition of low residual stress CoNiMnP hard magnetic thin films for magnetic MEMS actuators. J. Magn. Magn. Mater. 292, 49–58 (2005)CrossRefGoogle Scholar
  28. 28.
    Gutfleisch, O.: Controlling the properties of high density permanent magnetic materials. J. Phys. D: Appl. Phys. 33, R157–R172 (2000)CrossRefGoogle Scholar
  29. 29.
    Gutfleisch, O., Dempsey, N.M.: High performance μ-Magnets for Microelectromechanical Systems (MEMS). In: G. Asti, L. Pareti, and M. Ghidini (eds.) Magnetic Nanostructures in Modern Technology, pp. 167–194. Springer, Netherlands (2007)Google Scholar
  30. 30.
    Hai, N.H., Dempsey, N.M., Veron, M., Verdier, M., Givord, D.: An original route for the preparation of hard FePt. J. Magn. Magn. Mater. 257, 139–145 (2003)CrossRefGoogle Scholar
  31. 31.
    Hinz, D., Gutfleisch, O., Müller, K.-H.: High performance NdFeB magnets with a thickness of some 100 μm for MEMS applications. Proceedings of the 18th International. Workshop on High Performance Magnets and their Applications, 797 (2004)Google Scholar
  32. 32.
    Holmes, A.S., Guodong, H., Pullen, K.R.: Axial-flux permanent magnet machines for μ power generation. J. MEMS 14, 54–62 (2005)Google Scholar
  33. 33.
    Homburg, H., Sinnemann, Th., Methfessel, S., Rosenberg, M., Gu, B.X.: Sputtered NdFeB films of high coercivity. J. Magn. Magn. Mater. 83, 231–233 (1990)CrossRefGoogle Scholar
  34. 34.
    Kapitanov, B.A., Kornilov, N.V., Linetsky, Ya. L., Tsvetkov, V. Yu.: Sputtered permanent Nd-Fe-B magnets. J. Magn. Magn. Mater. 127, 289–297 (1993).Google Scholar
  35. 35.
    Katter, M., Ûstüner, K., Blank, R.: Model for calculating J(H) curves of Ni coated Nd-Fe-B magnets. Proceedings of the 19th International Workshop on Rare Earth Magnets and their Applications, 87–91 (2006)Google Scholar
  36. 36.
    Kumar, K., Das, D., Wettstein, E.: High coercivity, isotropic plasma sprayed Sm-Co magnets. J. Appl. Phys. 49, 2052–2054 (1978)CrossRefGoogle Scholar
  37. 37.
    Lagorce, L.K., Allen, M.G.: Micromachined polymer magnets. Proceedings of the Ninth Annual International Workshop on Micro Electro Mechanical Systems, 85–90 (1996).Google Scholar
  38. 38.
    Leistner, K., Thomas, J., Schlörb, H., Weisheit, M., Schultz, L., Fähler, S.: Highly coercive electrodeposited FePt films by postannealing in hydrogen. Appl. Phys. Lett. 85, 3498–3500 (2004)CrossRefGoogle Scholar
  39. 39.
    Lemke, H., Lang, T., Giiddenhenrich, T., Heiden, C.: Micro patterning of thin Nd-Fe-B films. J. Magn. Magn. Mater. 148, 426–432 (1995)CrossRefGoogle Scholar
  40. 40.
    Liu, W.F., Suzuki, S., Machida, K.: Magnetic properties of Nd–Fe–B film magnets prepared by RF sputtering. J. Magn. Magn. Mater. 308, 126–130 (2007)CrossRefGoogle Scholar
  41. 41.
    Myung, N.V., Park, D.-Y., Yoob, B.-Y., Sumodjob, P.T.A.: Development of electroplated magnetic materials for MEMS. J. Magn. Magn. Mater. 265, 189–198(2003)CrossRefGoogle Scholar
  42. 42.
    Nakano, M., Katoh, R., Fukunaga, H.: Fabrication of Nd–Fe–B thick-film magnets by high-speed PLD method. IEEE Trans. Magn. 39, 2863–2865 (2003)CrossRefGoogle Scholar
  43. 43.
    Ndao, C.B., Givord, D., Dempsey, N.M.: (2009, in preparation)Google Scholar
  44. 44.
    Okuda, T., Sugimura, A., Eryu, O., Serrona, L.K.E.B., Adachi, N., Sakamoto I., Nakanishi, A.: Nd–Fe–B thin films with perpendicular magnetic anisotropy and high coercivity prepared by pulsed laser annealing. Jpn. J. Appl. Phys. 42, 6859–6864 (2003)CrossRefGoogle Scholar
  45. 45.
    Overfelt, R.A., Anderson, C.D., Flanagan, W.F.: Plasma sprayed Fe76Nd16B8 permanent magnets. Appl. Phys. Lett. 49, 1799–1801 (1986)CrossRefGoogle Scholar
  46. 46.
    Pawlowski, B., Rahmig, A., Töpfer, J.: Preparation and properties of NdFeB thick films. 15th International Workshop on Rare Earth Magnets and their Applications 1045 (1998)Google Scholar
  47. 47.
    Pawlowski, B., Scharzer, S., Rahmig, A., Töpfer, J.: NdFeB thick films prepared by tape casting. J. Magn. Magn. Mat. 265, 337–344 (2003)CrossRefGoogle Scholar
  48. 48.
    Pina, E., Palomares, F.J., Garcia, M.A., Cebollada, de Hoyos, F.A., Romero, J.J., Hernando, A., Gonzalez, J.M.: Coercivity in SmCo hard magnetic films for MEMS applications. J. Magn. Magn. Mat. 290–291, 1234–1236 (2005)CrossRefGoogle Scholar
  49. 49.
    Raisigel, H., Cugat, O., Delamare, J.: Permanent magnet planar μ-generators. Sensors Actuators A 130–131, 438–444 (2006)CrossRefGoogle Scholar
  50. 50.
    Rhen, F.M.F., Hinds, G., O´Reilly, C. Coey, J.M.D.: Electrodeposited FePt films. IEEE Trans. Magn. 39, 2699–2701 (2003)CrossRefGoogle Scholar
  51. 51.
    Rhen, F.M.F., Backen, E., Coey, J.M.D.: Thick-film permanent magnets by membrane electrodeposition. J. Appl. Phys. 97, 113908-4 (2005)CrossRefGoogle Scholar
  52. 52.
    Rieger, G., Wecker, J., Rodewald, W., Sattler, W., Bach, Fr.-W., Duda, T., Unterberg, W.: Nd–Fe–B permanent magnets (thick films) produced by a vacuum-plasma-spraying process. J. Appl. Phys. 87, 5329–5331 (2000)CrossRefGoogle Scholar
  53. 53.
    Rodewald, W., Wall, B., Fernengel, W., Katter, M.: Production of thin flexible RE magnet-foils. Proceedings of the 15th International Workshop on Rare Earth Magnets and their Applications, 1021 (1998)Google Scholar
  54. 54.
    Romero, J.J., Cuadrado, R., Pina, E., de Hoyos, A., Pigazo, F., Palomares F.J., Hernando, A., Sastre, R., Gonzalez, J.M.: Anisotropic polymer bonded hard-magnetic films. J. Appl. Phys. 99, 08N303-3 (2006)CrossRefGoogle Scholar
  55. 55.
    Rostaing, H., Stepanek, J., Cugat, O., Dieppedale, C., Delamare, J.: Magnetic, out-of-plane, totally integrated bistable μ-actuator. Proc. TRANSDUCERS '05 2, 1366–1370 (2005)Google Scholar
  56. 56.
    Skomski, R., Coey, J.M.D: Permanent Magnetism. Institute of Physics, Bristol (1999)Google Scholar
  57. 57.
    Speliotis, T., Niarchos, D.: Microstructure and magnetic properties of SmCo films. J. Mag. Mag. Mat. 290, 1195–1197 (2005)CrossRefGoogle Scholar
  58. 58.
    Vacuumschmelze GmbH, private communication (2006).Google Scholar
  59. 59.
    Vieux-Rochaz, L., Dieppedale, C., Desloges, B., Gamet, D., Barragatti, C., Rostaing, H., Meunier-Carus, J.: Electrodeposition of hard magnetic CoPtP material and integration into magnetic MEMS. J. Micromech. Microeng. 16, 219–224 (2006)CrossRefGoogle Scholar
  60. 60.
    Walther, A., Khlopkov, K., Gutfleisch, O., Givord, D., Dempsey, N.M.: Evolution of magnetic and microstructural properties of thick sputtered NdFeB films with processing temperature. J. Magn. Magn. Mat. 316, 174–176 (2007)CrossRefGoogle Scholar
  61. 61.
    Walther, A., Givord, D., Dempsey, N.M., Khlopkov, K., Gutfleisch, O.: Structural, magnetic and mechanical properties of 5 μm thick SmCo films suitable for use in Micro-Electro-Mechanical-Systems. J. Appl. Phys. 103, 043911-043911-5 (2008)CrossRefGoogle Scholar
  62. 62.
    Walther, A., Marcoux, C., Desloges, B., Grechishkin,R., Givord, D., Dempsey, N.M.: Micro-patterning of NdFeB and SmCo magnet films for integration into Micro-Electro-Mechanical-Systems. J. Magn. Magn. Mater. (Accepted)Google Scholar
  63. 63.
    Wang, W., Yao, Z., Chen, J.C., Fang, J.: Composite elastic magnet films with hard magnetic feature. J. Micromech. Microeng. 14, 1321–1327 (2004)CrossRefGoogle Scholar
  64. 64.
    Wilson, S.A. et al.: New materials for micro-scale sensors and actuators, an engineering review. Materials Science and Engineering R 56, 1–129 (2007)CrossRefGoogle Scholar
  65. 65.
    Yamashita, S., Yamasaki, J., lkeda, M., lwabuchi, N.: Anisotropic Nd-Fe-B thin-film magnets for millli-size motor. J. Appl. Phys. 70, 6627–6629 (1991)CrossRefGoogle Scholar
  66. 66.
    Yan, J., Luanava, S., Casasanta, V.: Magnetic actuation for MEMS scanners for retinal scanning displays. SPIE Proc. 4985 MOEMS Displays and Imaging Systems, July 1–6 (2004)Google Scholar
  67. 67.
    Zana, I., Zangari, G.: Electrodeposition of Co-Pt films with high perpendicular anisotropy. Electrochem. Solid-State Lett. 6(12), C153–C156 (2003)CrossRefGoogle Scholar
  68. 68.
    Zana, I., Zangari, G., Park, J.-W., Allen, M.G.: Electrodeposited Co–Pt micron-size magnets with strong perpendicular magnetic anisotropy for MEMS applications. J. Magn. Magn. Mat. 272–276, e1775–e1776 (2004)CrossRefGoogle Scholar

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© Springer Science+Business Media, LLC 2009

Authors and Affiliations

  1. 1.Institut Néel, CNRS-UJFGrenobleFrance

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