High-Temperature Samarium Cobalt Permanent Magnets

  • Oliver Gutfleisch


This chapter reviews the development of SmCo-type magnets over the last 40 years. First, the physical metallurgy and crystal structures are considered; then the focus is on the recent developments in high-temperature Sm(CobalFe w Cu x Zr y ) z magnets suitable for operation temperatures up to 500°C. It is elucidated that the evolution of coercivity and microchemistry in the respective phases of the heterogeneous nanostructure as well as magnetic domain structure is very sensitive to details of the processing procedure, especially to the slow cooling ramp as the last step where the hard magnetic properties evolve. These changes give rise to rather complex pinning mechanisms in a three-phase precipitation structure, which again depend in a subtle manner on the microchemistry of the 1:5-type cell boundary phase in the 2:17-type magnets. It is the amount and distribution of Cu in and at the cell boundary phase which is the prevalent factor determining the pinning strength and which can yield a non-monotonic temperature dependence of coercivity. The chapter concludes with an overview of novel non-equilibrium processing routes used to obtain SmCo-type nanocomposites.


Domain Wall Slow Cool Isothermal Aging Magnetic Force Microscopy High Coercivity 
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.


  1. 1.
    Al-Omari, I.A., J. Shobaki, R. Skomski, D. Leslie-Pelecky, J. Zhou and D.J. Sellmyer. (2002). High-temperature magnetic properties of SmCo6.7 xCu0.6Tix magnets. Physica B: Cond. Matter 321: 107–111.CrossRefGoogle Scholar
  2. 2.
    Barthem, V.M.T.S., D. Givord, M.F. Rossignol and P. Tenaud. (2002). An approach to coercivity relating coercive field and activation volume. Physica B 319: 127–132.CrossRefGoogle Scholar
  3. 3.
    Buschow, K.H.J. and A.S. van der Goot. (1968). Intermetallic compounds in the system samarium-cobalt. J. Less-Common Met. 14: 323–328.CrossRefGoogle Scholar
  4. 4.
    Buschow, K.H.J. and A.S. van der Goot. (1971). Composition and crystal structure of hexagonal Cu-rich rare earth-copper compounds. Acta Cryst. B 27: 1085–1088.CrossRefGoogle Scholar
  5. 5.
    Buschow, K.H.J., (1989).  Chapter 1, Permanent magnet materials based on 3d-rich ternary compounds. In: Ferromagnetic Materials, vol. 4, E. P. Wohlfarth and K.H.J. Buschow (eds.), North-Holland Elsevier, Amsterdam, Netherlands.Google Scholar
  6. 6.
    Buschow, K.H.J. (1997).  Chapter 4, Magnetism and processing of permanent magnet materials. In: Handbook of Magnetic Materials, vol. 10, K.H.J. Buschow (ed.), North Holland Elsevier, Amsterdam, Netherlands.Google Scholar
  7. 7.
    Cataldo, L., A. Lefevre, F. Ducret, M.Th. Cohen-Adat, C.H. Allibert and N. Valignat. (1996). Binary system Sm-Co: revision of the phase diagram in the Co rich field. J. Alloys Comp. 241: 216–223.CrossRefGoogle Scholar
  8. 8.
    Chen, C., M.S. Walmer, M.H. Walmer, S. Liu, G.E. Kuhl and G. Simon. (1998). Sm2(Co, Fe, Cu, Zr)17 magnets for use at temperature ≥ 400ºC. J. Appl. Phys. 83: 6706–6708.CrossRefGoogle Scholar
  9. 9.
    Chen, C., M.S. Walmer, M.H. Walmer, S. Liu, G.E. Kuhl and G.K. Simon. (1999). New series of Sm2TM17 magnet materials for application at temperatures up to 550°C. In: MRS Symp. Proc. Advanced Hard and Soft Magnets, vol. 577, J. Fidler, M. Coey et al. (eds.), Materials Research Society, Pittsburgh, USA, pp. 277–287.Google Scholar
  10. 10.
    Chen, C., M.H. Walmer, E.H. Kottcamp and W. Gong. (2001). Surface reaction and Sm depletion at 550°C for high temperature Sm-TM magnets. IEEE Trans. Mag. 37: 2531–2533.CrossRefGoogle Scholar
  11. 11.
    Chikazumi, S. (1997). Physics of Ferromagnetism, 2nd ed. Oxford Science Publications, Oxford, p. 276.Google Scholar
  12. 12.
    Coey, J.M.D. (ed.). (1996) Rare Earth Iron Permanent Magnets. Clarendon Press, Oxford, UK.Google Scholar
  13. 13.
    Craik, D.J. and E.D. Isaac. (1960). Magnetic interaction domains. Proc. Phys. Soc. (Research Notes) 76.Google Scholar
  14. 14.
    Cullity, B.D. (1972). Introduction to Magnetic Materials. Addison-Wesley Publishing Company, Reading, MA.Google Scholar
  15. 15.
    Delannay, F., S. Derkaoui and C.H. Allibert. (1987a). The influence of zirconium on Sm(CoFeCuZr)7.2 alloys for permanent magnets I: identification of the phases by transmission electron microscopy. J. Less-Common Met. 134: 249–262.CrossRefGoogle Scholar
  16. 16.
    Delannay, F., S. Derkaoui and C.H. Allibert. (1987b). Transmission electron microscopy of Sm(CoFeCuZr)7.2 alloys for permanent magnet. Micron Microscopica Acta 18: 243.CrossRefGoogle Scholar
  17. 17.
    Derkaoui, S., C.H. Allibert, F. Delannay and J. Laforest. (1987). The influence of zirconium on Sm(Co,Fe,Cu,Zr)7.2 alloys for permanent magnets II: composition and lattice constants of the phases in heat-treated materials. J. Less-Common Met. 136: 75–86.CrossRefGoogle Scholar
  18. 18.
    Derkaoui, S. and C.H. Allibert. (1989). Redetermination of the phase equilibria in the system Sm-Co-Cu for Sm content 0–20 at.% at 850°C. J. Less-Common Met. 154: 309–315.CrossRefGoogle Scholar
  19. 19.
    Derkaoui, S., N. Valignat and C.H. Allibert. (1996a). Co corner of the system Sm-Co-Zr: decomposition of the phase 1:7 and equilibria at 850°C. J. Alloys Comp. 235: 112–119.CrossRefGoogle Scholar
  20. 20.
    Derkaoui, S., N. Valignat and C.H. Allibert. (1996b). Phase equilibria at 1150°C in the Co-rich alloys Sm-Co-Zr and structure of the 1:7 phase. J. Alloys Comp. 232: 296–301.CrossRefGoogle Scholar
  21. 21.
    Ding, J., P.G. McCormick and R. Street. (1994). A study of Sm13(Co1-xFex)87 prepared by mechanical alloying. J. Magn. Magn. Mat. 135: 200–204.CrossRefGoogle Scholar
  22. 22.
    Durst, K.D. and H. Kronmüller. (1985). Magnetic hardening mechanisms in sintered Nd-Fe-B and Sm(Co,Fe,Cu,Zr)7.6 permanent magnets. Proc. 4th Int. Symp. Magn. Anisotropy and Coercivity in RETM Alloys, Dayton, USA, pp. 725–735.Google Scholar
  23. 23.
    Durst, K.D., H. Kronmüller, F.T. Parker and H. Oesterreicher. (1986). Temperature dependence of coercivity of cellular Sm2Co17-SmCo5 permanent magnets. Phys. Stat. Sol. (a) 95: 213–219.CrossRefGoogle Scholar
  24. 24.
    Durst, K.D., H. Kronmüller and W. Ervens. (1988a). Investigations of the magnetic properties and demagnetisation processes of an extremely high coercive Sm(Co,Cu,Fe,Zr)7.6 permanent magnet – I Determination of intrinsic magnetic material parameters. Phys. Stat. Sol. (a) 108: 403–416.CrossRefGoogle Scholar
  25. 25.
    Durst, K.D., H. Kronmüller and W. Ervens. (1988b). Investigations of the magnetic properties and demagnetisation processes of an extremely high coercive Sm(Co,Cu,Fe,Zr)7.6 permanent magnet – II The coercivity mechanism. Phys. Stat. Sol. (a) 108: 705–719.CrossRefGoogle Scholar
  26. 26.
    Ervens, W. (1979). Rare earth-transition metal 2:17 permanent magnet alloys, state and trends. Goldschmidt Informiert 48: 3–9.Google Scholar
  27. 27.
    Fidler, J. and P. Skalicky. (1982a). Coercivity of precipitation hardened cobalt rare earth 17:2 permanent magnets. J. Magn. Magn. Mat. 30: 58–70.CrossRefGoogle Scholar
  28. 28.
    Fidler, J. and P. Skalicky (1982b, September). Domain wall pinning in REPM. In: Proc. 3rd Int. Symp. Magnetic Anisotropy and Coercivity in Rare Earth-Transition Metal Alloys, J. Fidler(ed.), Baden, Austria, pp. 585–597.Google Scholar
  29. 29.
    Gavigan, J.P. and D. Givord. (1990). Intrinsic and extrinsic properties of rare earth-transition metal compounds and permanent magnets. J. Magn. Magn. Mat. 84: 288–298.CrossRefGoogle Scholar
  30. 30.
    Givord, D., A. Lienard, P. Tenaud and T. Viadieu. (1987). Magnetic viscosity in Nd-Fe-B sintered magnets. J. Magn. Magn. Mat. 67: L281–L285.CrossRefGoogle Scholar
  31. 31.
    Givord, D., P. Tenaud and T. Viadieu. (1988). Coercivity mechanisms in ferrites and rare earth transition metal sintered magnets(SmCo5,Nd-Fe-B). IEEE Trans. Magn. 24: 1921–1923.CrossRefGoogle Scholar
  32. 32.
    Givord, D., M. Rossignol and V.M.T.S. Barthem. (2003). The physics of coercivity. J. Magn. Magn. Mat. 258–259: 1–5.CrossRefGoogle Scholar
  33. 33.
    Goll, D., I. Kleinschroth, W. Sigle and H. Kronmüller. (2000). Melt-spun precipitation-hardened Sm2(Co,Cu,Fe,Zr)17 magnets with abnormal temperature dependence of coercivity. Appl. Phys. Lett. 76: 1054–1056.CrossRefGoogle Scholar
  34. 34.
    Goll, D. and H. Kronmüller. (2002). Micromagnetic analysis of pinning-hardened nanostructured, nanocrystalline Sm2Co17 based alloys. Scripta Mat. 47: 545–550.CrossRefGoogle Scholar
  35. 35.
    Goll, D., H. Kronmüller and H.H. Stadelmaier. (2004). Micromagnetism and the microstructure of high-temperature permanent magnets. J. Appl. Phys. 96: 6534–6545.CrossRefGoogle Scholar
  36. 36.
    Gopalan, R., K. Hono, A. Yan and O. Gutfleisch. (2009). Direct evidence on Cu-concentration variation and its correlation to coercivity in Sm(Co0.74Fe0.1Cu0.12Zr0.4)7.4 ribbons, Scripta. Mat. 60: 764–767.Google Scholar
  37. 37.
    Gutfleisch, O. and I.R. Harris. (1996). Fundamental and practical aspects of the hydrogenation, disproportionation, desorption and recombination process. J. Phys. D: Appl. Phys. 29: 2255–2265.CrossRefGoogle Scholar
  38. 38.
    Gutfleisch, O., M. Kubis, A. Handstein, K.H. Müller and L. Schultz. (1998). Hydrogenation disproportionation desorption recombination in Sm–Co alloys by means of reactive milling. Appl. Phys. Lett. 73: 3001–3003.CrossRefGoogle Scholar
  39. 39.
    Gutfleisch, O. (2000). Controlling the properties of high energy density permanent magnetic materials by different processing routes. J. Phys. D: Appl. Phys. 33: R157–R172.CrossRefGoogle Scholar
  40. 40.
    Gutfleisch, O., N.M. Dempsey, A. Yan, K.-H. Müller and D. Givord. (2004). Coercivity analysis of melt-spun Sm2(Co,Fe,Cu,Zr)17. J . Magn. Magn. Mat. 272–276: 647–649.CrossRefGoogle Scholar
  41. 41.
    Gutfleisch, O., K.-H. Müller, K. Khlopkov, M. Wolf, A. Yan, R. Schäfer, T. Gemming and L. Schultz. (2006). Evolution of magnetic domain structures and coercivity in high-performance SmCo 2:17 type permanent magnets. Acta Mat. 54: 997–1008.CrossRefGoogle Scholar
  42. 42.
    Hadjipanayis, G.C. (1996). Microstructure and magnetic domains. In: Rare-Earth Iron Permanent Magnets, J.M.D. Coey (ed.), Oxford University Press, Oxford, UK, pp. 286–335.Google Scholar
  43. 43.
    Hadjipanayis, G.C., W. Tang, Y. Zhang, S.T. Chui, J.F. Liu, C. Chen and H. Kronmüller. (2000). High temperature 2:17 magnets: relationship of magnetic properties to microstructure and processing. IEEE Trans. Magn. 36: 3382–3387.CrossRefGoogle Scholar
  44. 44.
    Handstein, A., M. Kubis, O. Gutfleisch, B. Gebel and K.H. Müller. (1999). HDDR of Sm–Co alloys using high hydrogen pressures. J. Magn. Magn. Mat. 192: 73–76.CrossRefGoogle Scholar
  45. 45.
    Handstein, A., A. Yan, G. Martinek, O. Gutfleisch, K.H. Müller and L. Schultz. (2003). Stability of magnetic properties of Sm2Co17-type magnets at operating temperatures larger than 400ºC. IEEE Trans. Magn. 39: 2923–2925.CrossRefGoogle Scholar
  46. 46.
    Hofer, F. (1970). Physical metallurgy and magnetic measurements of SmCo5-SmCu5 alloys. IEEE Trans. Magn. 6: 221–224.CrossRefGoogle Scholar
  47. 47.
    Hubert, A. and R. Schäfer (1998). Magnetic Domains – The Analysis of Magnetic Microstructures. Springer Verlag, Berlin, Germany.Google Scholar
  48. 48.
    Kardelky, S., A. Gebert, O. Gutfleisch, A. Handstein, G. Martinek and L. Schultz. (2004). Corrosion behavior of Sm-Co based permanent magnets in oxidizing environments. IEEE Trans. Magn. 40: 2931–2933.CrossRefGoogle Scholar
  49. 49.
    Katter, M., J. Weber, W. Assmus, P. Schrey and W. Rodewald. (1996). A new model for the coercivity mechanism of Sm2(Co,Fe,Cu,Zr)17 magnets. IEEE Trans. Magn. 32: 4815–4817.CrossRefGoogle Scholar
  50. 50.
    Katter, M. (1998). Coercivity calculation of Sm2(Co,Fe,Cu,Zr)17 magnets. J. Appl. Phys. 83: 6721–6723.CrossRefGoogle Scholar
  51. 51.
    Kerschl, P., A. Handstein, K. Khlopkov, O. Gutfleisch, D. Eckert, K. Nenkov, J.-C. Téllez-Blanco, R. Grössinger, K.-H. Müller and L. Schultz. (2005). High-field magnetisation of SmCo5 xCux (x ≈ 2.5) determined in pulse fields up to 48 T. J. Magn. Magn. Mat. 290–291(part 1): 420–423.Google Scholar
  52. 52.
    Khan, Y. (1973). The crystal structures of R2Co17 intermetallic compounds. Acta Crystall. Section B 29: 2502–2507.CrossRefGoogle Scholar
  53. 53.
    Khlopkov, K., O. Gutfleisch, D. Eckert, D. Hinz, B. Wall, W. Rodewald, K.-H. Müller, and L. Schultz. (2004). Local texture in Nd-Fe-B sintered magnets with maximised energy density. J. Alloys Comp. 365: 259–265.CrossRefGoogle Scholar
  54. 54.
    Kronmüller, H., K.-D. Durst, W. Ervens and W. Fernengel. (1984). Micromagnetic analysis of precipitation hardened permanent magnets. IEEE Trans. Magn. 20: 1569–1571.CrossRefGoogle Scholar
  55. 55.
    Kronmüller, H. and D. Goll. (2002). Micromagnetic theory of the pinning of domain walls at phase boundaries. Physica B 319: 122–126.CrossRefGoogle Scholar
  56. 56.
    Kubis, M., A. Handstein, B. Gebel, O. Gutfleisch, K.H. Müller and L. Schultz. (1999). Highly coercive SmCo5 magnets prepared by a modified hydrogenation-disproportionation-desorption-recombination process. J. Appl. Phys. 85: 5666–5668.CrossRefGoogle Scholar
  57. 57.
    Kumar, K. (1988). RETM5 and RE2TM17 permanent magnets development. J. Appl. Phys. 63: R13–R57.CrossRefGoogle Scholar
  58. 58.
    Lectard, E., C.H. Allibert and R. Ballou. (1994). Saturation magnetization and anisotropy fields in the Sm(Co1–xCux)5 phases. J. Appl. Phys. 75: 6277–6279.CrossRefGoogle Scholar
  59. 59.
    Lefèvre, A., L. Cataldo, M.Th. Cohen-Adad, and B.F. Mentzen. (1997). A representation of the Sm-Co-Zr-Cu-Fe quinary system: a tool for optimisation of 2/17 permanent magnets. J. Alloys Comp. 262–263: 129–133.CrossRefGoogle Scholar
  60. 60.
    Li, D. and K.J. Strnat. (1984). Domain structures of two Sm-Co-Cu-Fe-Zr “2–17” magnets during magnetization reversal. J. Appl. Phys. 55: 2103–2105.CrossRefGoogle Scholar
  61. 61.
    Liu, J.F., T. Chui, D. Dimitrov and G.C. Hadjipanayis. (1998a). Abnormal temperature dependence of intrinsic coercivity in Sm(Co, Fe, Cu, Zr)z powder materials. Appl. Phys. Lett. 73: 3007–3009.CrossRefGoogle Scholar
  62. 62.
    Liu, J.F., Y. Zhang, Y. Ding, D. Dimitrov, and G.C. Hadjipanayis (1998b). Rare earth permanent magnets for high temperature applications. In: Proc. of 15th Int. Workshop on Rare Earth Magnets and their Appl., Dresden, Germany, vol. 2, pp. 607–622.Google Scholar
  63. 63.
    Liu, J.F., Y. Zhang, D. Dimitrov and G.C. Hadjipanayis. (1999). Microstructure and high temperature magnetic properties of Sm(Co,Cu,Fe,Zr)z (z = 6.7–9.1) permanent magnets. J. Appl. Phys. 85: 2800–2804.CrossRefGoogle Scholar
  64. 64.
    Livingston, J.D. and M.D. McConnell. (1972). Domain-wall energy in cobalt-rare-earth compounds. J. Appl. Phys. 43: 4756–4762.CrossRefGoogle Scholar
  65. 65.
    Livingston, J.D. (1975). Domains in sintered Co-Cu-Fe-Sm magnets. J. Appl. Phys. 46: 5259–5262.CrossRefGoogle Scholar
  66. 66.
    Livingston, J.D. and D.L. Martin. (1977). Microstructure of aged (Co,Cu,Fe)7Sm magnets. J. Appl. Phys. 48: 1350–1354.CrossRefGoogle Scholar
  67. 67.
    Matthias, T., G. Zehetner, J. Fidler, W. Scholz, T. Schrefl, D. Schobinger and G. Martinek. (2002). TEM-analysis of Sm(Co,Fe,Cu,Zr)z magnets for high-temperature applications. J. Magn. Magn. Mat. 242–245: 1353–1355.CrossRefGoogle Scholar
  68. 68.
    Maury, C., L. Rabenberg and C.H. Allibert. (1993). Genesis of the cell microstructure in the Sm(Co,Fe,Cu,Zr) permanent magnets with 2:17 type. Phys. Stat. Sol. (a) 140: 57–72.CrossRefGoogle Scholar
  69. 69.
    Meyer-Liautaud, F., S. Derkaoui, C.H. Allibert and R. Castanet. (1987). Structural and thermodynamic data on the pseudobinary phases R(Co1 xCux)5 with R ≡ Sm, Y, Ce. J. Less-Common Met. 127: 231–242.CrossRefGoogle Scholar
  70. 70.
    Morita, Y., T. Umeda and Y. Kimura. (1987). Phase transformation at high temperature and coercivity of Sm(Co,Cu,Fe,Zr)7-9 magnet alloys. IEEE Trans. Magn. 23: 2702–2704.CrossRefGoogle Scholar
  71. 71.
    Nagel, H. (1979). Coercivity and microstructure of Sm(Co0.87Cu0.13)7.8. J. Appl. Phys. 50: 1026–1030.CrossRefGoogle Scholar
  72. 72.
    Nesbitt, E.A., R.H. Willens, R.C. Sherwood and E. Bühler. (1968). New permanent magnet materials. Appl. Phys. Lett. 12: 361–362.CrossRefGoogle Scholar
  73. 73.
    Oesterreicher, H., F.T. Parker and M. Misroch. (1979). Giant intrinsic magnetic hardness in SmCo5-xCux. J. Appl. Phys. 50: 4273–4278.CrossRefGoogle Scholar
  74. 74.
    Ojima, T., S. Tomizawa, T. Yoneyama and T. Hori. (1977). Magnetic properties of new type of rare-earth cobalt magnets. IEEE Trans. Magn. 13: 1317–1319.CrossRefGoogle Scholar
  75. 75.
    Panagiotopoulos, I., M. Gjoka and D. Niarchos. (2002). Temperature dependence of the activation volume in high-temperature Sm(Co,Fe,Cu,Zr)Z magnets. J. Appl. Phys. 92: 7693–7695.CrossRefGoogle Scholar
  76. 76.
    Perkins, R.S., S. Gaiffi and A. Menth. (1975). Permanent magnet properties of Sm2(Co,Fe)17. IEEE Trans. Magn. 11: 1431–1433CrossRefGoogle Scholar
  77. 77.
    Perkins, R.S. and S. Strässler. (1977). Interpretation of the magnetic properties of pseudobinary Sm2(Co,M)17 compounds. I. Magnetocrystalline anisotropy. Phys. Rev. B 15: 477–489; Interpretation of the magnetic properties of pseudobinary Sm2(Co,M)17 compounds. II. Magnetization. Phys. Rev. B 15: 490–495.CrossRefGoogle Scholar
  78. 78.
    Perry, A.J. and A. Menth. (1975). Permanent magnets based on Sm(Co,Cu,Fe)z. IEEE Trans. Magn. 11: 1423–1425.CrossRefGoogle Scholar
  79. 79.
    Perry, A.J. (1977). The constitution of copper-hardened samarium-cobalt permanent magnets. J. Less-Common Met. 51: 153–162.CrossRefGoogle Scholar
  80. 80.
    Popov, A.G., A.V. Korolev and N.N. Shchegoleva. (1990). Temperature dependence of the coercive force of Sm(Co,Fe,Cu,Zr)7.3 alloys. Phys. Met. Metall. 69: 100–106.Google Scholar
  81. 81.
    Rabenberg, L., R.K. Mishra, and G. Thomas. (1982a). Microstructure of precipitation hardened SmCo permanent magnets. J. Appl. Phys. 53: 2389–2391.CrossRefGoogle Scholar
  82. 82.
    Rabenberg, L., R.K. Mishra, and G. Thomas. (1982b, September). Development of the cellular microstructure in the SmCo7.4-type magnets. In: Proc. 3rd Int. Symp. Magnetic Anisotropy and Coercivity in Rare Earth-Transition Metal Alloys, J. Fidler (ed.), Baden, Austria, pp. 599–608.Google Scholar
  83. 83.
    Ray, A.E. (1984). Metallurgical behavior of Sm(Co,Fe,Cu,Zr)z alloys. J. Appl. Phys. 55: 2094–2096.CrossRefGoogle Scholar
  84. 84.
    Ray, A.E. and S. Liu. (1992). Recent progress in 2:17 type permanent magnets. Proc. 12th Int. Workshop on RE Magnets and their Appl., Canberra, Australia, pp. 552–573.Google Scholar
  85. 85.
    Schobinger, D., O. Gutfleisch, D. Hinz, K.H. Müller, L. Schultz and G. Martinek. (2002). High temperature magnetic properties of 2:17 Sm–Co magnets. J. Magn. Magn. Mat. 242–245: 1347–1349.CrossRefGoogle Scholar
  86. 86.
    Schultz, L., K. Schnitzke, J. Wecker, M. Katter and C. Kuhrt. (1991). Permanent magnets by mechanical alloying. J. Appl. Phys. 70: 6339–6344.CrossRefGoogle Scholar
  87. 87.
    Skomski, R. (1997). Domain-wall curvature and coercivity in pinning type Sm-Co magnets. J. Appl. Phys. 81: 6527–5629.Google Scholar
  88. 88.
    Skomski, R. and J.M.D. Coey. (1999). Permanent Magnetism. Institute of Physics, Bristol.Google Scholar
  89. 89.
    Skomski, R., A. Kashyap, Y. Qiang, and D.J. Sellmyer. (2003). Exchange through nonmagnetic insulating matrix. J. Appl. Phys. 93: 6477–6479.CrossRefGoogle Scholar
  90. 90.
    Stadelmaier, H.H., E.-Th. Henig, G. Schneider and G. Petzow. (1988). The metallurgy of permanent magnets based on Co17Sm2. Z. Metallkd. 79: 313–316.Google Scholar
  91. 91.
    Stadelmaier, H.H., B. Reinsch, and G. Petzow. (1998). Samarium-cobalt phase equilibria revisited; relevance to permanent magnets. Z. Metallkd. 89: 114–118.Google Scholar
  92. 92.
    Stadelmaier, H.H., D. Goll, H. Kronmüller. (2005). Permanent magnet alloys based on Sm2Co17; phase evolution in the quinary system Sm-Zr-Fe-Co-Cu. Z. Metallkd. 96: 17–23.Google Scholar
  93. 93.
    Streibl, B., J. Fidler and T. Schrefl. (2000). Domain wall pinning in high temperature Sm(Co,Fe,Cu,Zr)7-8 magnets. J. Appl. Phys. 87: 4765–4767.CrossRefGoogle Scholar
  94. 94.
    Strnat, K.J., G. Hoffer, J. Olson, W. Ostertag and J.J. Becker. (1967). A family of new cobalt-base permanent magnetic materials. J. Appl. Phys. 38: 1001–1002.CrossRefGoogle Scholar
  95. 95.
    Strnat, K.J. (1988).  Chapter 2, Rare earth–cobalt permanent magnets. In: Ferromagnetic Materials, vol. 4, E.P. Wohlfarth, K.H.J. Buschow (eds.), North-Holland, Amsterdam, Netherlands.Google Scholar
  96. 96.
    Strnat, K.J. and R.M.W. Strnat. (1991). Rare earth–cobalt permanent magnets. J. Magn. Magn. Mat. 100: 38–56.CrossRefGoogle Scholar
  97. 97.
    Tang, H., Y. Liu and D.J. Sellmyer. (2002). Nanocrystalline Sm12.5(Co,Zr)87.5 magnets: synthesis and magnetic properties. J. Magn. Magn. Mat. 241: 345–356.CrossRefGoogle Scholar
  98. 98.
    Tang, W., Y. Zhang and G.C. Hadjipanayis. (2000). Effect of Zr on the microstructure and magnetic properties of Sm(CobalFe0.1Cu0.088Zrx)8.5 magnets. J. Appl. Phys. 87: 399–403.CrossRefGoogle Scholar
  99. 99.
    Tang, W., A.M. Gabbay, Y. Zhang, G.C. Hadjipanayis and H. Kronmüller. (2001). Temperature dependence of coercivity and magnetisation reversal in Sm(CobalFe0.1CuyZr0.4)7.0 magnets. IEEE Trans. Magn. 37: 2515–2517.CrossRefGoogle Scholar
  100. 100.
    Walmer, M.S., C.H. Chen and M.H. Walmer. (2000). A new class of Sm-TM magnets for operating temperatures up to 550°C. IEEE Trans. Magn. 36: 3376–3381.CrossRefGoogle Scholar
  101. 101.
    Wecker, J., M. Katter and L. Schultz. (1991). Mechanically alloyed Sm-Co materials. J. Appl. Phys. 69: 6058–6060.CrossRefGoogle Scholar
  102. 102.
    Xiong, X.Y., T. Ohkubo, T. Koyama, K. Ohashi, T. Tawara and K. Hono. (2004). The microstructure of sintered Sm(Co0.72Fe0.20Cu0.055Zr0.025)7.5 permanent magnet studied by atom probe. Acta Mat. 52: 737–748.CrossRefGoogle Scholar
  103. 103.
    Yan, A., W.-Y. Zhang, H.-W. Zhang and B. Shen. (2000). Melt-spun magnetically anisotropic SmCo5 ribbons with high permanent performance. J. Magn. Magn. Mat. 210: 10–14.CrossRefGoogle Scholar
  104. 104.
    Yan, A., A. Bollero, O. Gutfleisch and K.H. Müller. (2002a). Microstructure and magnetization reversal in nanocomposite SmCo5/Sm2Co17 magnets. J. Appl. Phys. 91: 2192–2196.CrossRefGoogle Scholar
  105. 105.
    Yan, A., A. Bollero, K.-H. Müller and O. Gutfleisch. (2002b). Fast development of high coercivity in melt-spun Sm(Co,Fe,Cu,Zr)z magnets. Appl. Phys. Lett. 80: 1243–1245,CrossRefGoogle Scholar
  106. 106.
    Yan, A., A. Bollero, K.H. Müller and O. Gutfleisch. (2002c). Influence of Fe, Zr and Cu on microstructure and crystallographic texture of melt-spun 2:17 SmCo ribbons. J. Appl. Phys. 91: 8825–8827.CrossRefGoogle Scholar
  107. 107.
    Yan, A., K.H. Müller and O. Gutfleisch. (2002d). Highly coercive melt-spun Sm(Co, Fe, Cu, Zr)z magnets prepared by simple processing. IEEE Trans. Magn. 38: 2937–2939.CrossRefGoogle Scholar
  108. 108.
    Yan, A., O. Gutfleisch, T. Gemming and K.-H. Müller. (2003a). Microchemistry and reversal mechanism in 2:17-type Sm-Co magnets. Appl. Phys. Lett. 83: 2208–2210.CrossRefGoogle Scholar
  109. 109.
    Yan, A., O. Gutfleisch, A. Handstein, T. Gemming and K.-H. Müller. (2003b). Microstructure, microchemistry, and magnetic properties of melt-spun Sm(Co,Fe,Cu,Zr)y magnets. J. Appl. Phys. 93: 7975–7977.CrossRefGoogle Scholar
  110. 110.
    Yan, A., A. Bollero, O. Gutfleisch, K.-H. Müller, L. Schultz, (2004). Melt-spun precipitation hardened Sm(Co,Fe,Cu,Zr)z magnets, Mat. Sci. Eng. A375–377: 1169–1172.Google Scholar
  111. 111.
    Yang, W., W. Ping, S. Zhenhua and Z. Shouzeng. (1992). 2:17 type temperature compensated magnets with high coercivity. In: Proc. of the 12th Int. Workshop on RE Magnets and their Appl., Canberra, Australia, pp. 249–257.Google Scholar
  112. 112.
    Zhang, Y., W. Tang. G.C. Hadjipanayis, C. Chen, C. Nelson and K. Krishnan. (2000). Evolution of microstructure, microchemistry and coercivity in 2:17 type Sm–Co magnets with heat treatment. IEEE Trans. Magn. 37: 2525–2527.CrossRefGoogle Scholar
  113. 113.
    Zhou, J., I.A. Al-Omari, J P. Liu and D.J. Sellmyer. (2000). Structure and magnetic properties of SmCo7-xTix with TbCu7-type structure. J. Appl. Phys. 87: 5299–5301.CrossRefGoogle Scholar
  114. 114.
    Zhou, J., R. Skomski, and D.J. Sellmyer. (2003). Magnetic hysteresis of mechanically alloyed Sm–Co nanocrystalline powders. J. Appl. Phys. 93: 6495–6497.CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC 2009

Authors and Affiliations

  1. 1.Leibniz Institute for Solid State and Materials Research (IFW Dresden)Institute for Metallic MaterialsDresdenGermany

Personalised recommendations