Exchange Coupling in MnAlC/α-Fe Nanocomposite Magnets

  • J. S. Trujillo Hernandez
  • F. Maccari
  • L. G. Marshall
  • Jesús A. Tabares
  • G. A. Pérez Alcázar
Original Paper


Nanostructured composite materials consisting of exchange-coupled hard and soft magnetic phases are proposed as alternative for the development of high-energy product permanent magnets. In this work, we have examined the effects of soft magnetic α-Fe addition on the structure and magnetic properties of powders composed of hard magnetic Mn54.3Al44C1.7 compound. The optimum melt-spun ribbon precursor (with τ-phase structure, with magnetization of 88 emu/g and coercive field of 1.6 kOe) was obtained after annealing the ribbons at 500 C for 20 min. After the combination between the soft and the optimized hard phase, the intensity of τ-phase peaks measured by X-ray diffraction decreases. These changes can also be seen in the magnetic properties. The coercivity (∼ 500 Oe) tends to decrease with the annealing temperature, while the magnetization tends to increase up to 141 emu/g. Evidence of good exchange coupling between particles of Mn54.3Al44C1.7 and α-Fe, in the produced composite, was proved by the hysteresis loop and its corresponding Thamm-Hesse analysis.


MnAlC alloys Mössbauer spectroscopy Cryomilling 



The authors would like to acknowledge professor Laura Lewis and her Nanomagnetism Group and professor Oliver Gutfleisch and his Functional Materials Group for their kind support during the doctoral visit of J.S. Trujillo Hernandez, Dr. Semih Ener for the SEM images, and M.Sc. Jeferson Piamba for the Mossbauer data.

Funding Information

This work was in part financed by Colciencias (contract No. 110671250407), Centro de Excelencia de Nuevos Materiales CENM-Univalle, and COLCIENCIAS, under Contract 110671250407. The authors specially acknowledge INAPEM (project EU 691235) for the kind support to our group.


  1. 1.
    Coey, J.M.: Hard magnetic materials: a perspective. IEEE Trans. Magn. 47, 4671–4681 (2011)ADSCrossRefGoogle Scholar
  2. 2.
    Kuzmin, M.D., Skokov, K.P., Jian, H., Radulov, I., Gutfleisch, O.: Towards high performance permanent magnets without rare earths. J. Phys. Condens. Matter 26, 064205 (2014)CrossRefGoogle Scholar
  3. 3.
    Coey, J.M.: New permanent magnets; manganese compounds. J. Phys.: Condens. Matter 26, 064211 (2014)Google Scholar
  4. 4.
    Jian, H., Skokov, K.P., Gutfleisch, O.: Microstructure and magnetic properties of Mn–Al–C alloy powders prepared by ball milling. J. Alloys Compd. 622, 524–528 (2015)CrossRefGoogle Scholar
  5. 5.
    Park, J., Hong, Y.K., Lee, J., Lee, W., Choi, C.J., Xu, X., Lane, A.M.: Magnetization and Intrinsic Coercivity for τ-phase Mn54Al46/α-phase Fe65Co35 composite. J. Magn. 19(1), 55–58 (2014)CrossRefGoogle Scholar
  6. 6.
    Wang, H.X., Si, P.Z., Jiang, W., Liu, J.J., Lee, J.G., Choi, C.J., Ge, H.L.: Structure and magnetic properties of MnAl/α-Fe nano-composite powders prepared by high energy ball milling. Adv. Mater. Res. 287–290, 1492–1495 (2011)Google Scholar
  7. 7.
    Kneller, E.F., Hawig, R.: The exchange-spring magnet: a new material principle for permanent magnets. IEEE Trans. Magn. 27(4), 3588–3600 (1991)ADSCrossRefGoogle Scholar
  8. 8.
    Marshall, L.G., McDonald, I.J., Lewis, L.H.: Quantification of the strain-induced promotion of τ-MnAl via cryogenic milling. J. Magn. Magn. Mater. 404, 215 (2016)CrossRefGoogle Scholar
  9. 9.
    Larson, A.C., Von Dreele, R.B.: General structure analysis system (GSAS). Los Alamos National Laboratory Report LAUR, pp. 86–748 (2004)Google Scholar
  10. 10.
    Thamm, S., Hesse, J.: A simple plot indicating interactions between single-domain particles. J. Mag. Mag. Mat. 154, 254–262 (1996)ADSCrossRefGoogle Scholar
  11. 11.
    Varret, F., Teillet, J.: Unpublished MOSFIT Program. Maine University, France (n.d.)Google Scholar
  12. 12.
    Obi, O., Burns, L., Chen, Y., Fitchorov, T., Kim, S., Hsu, K., Heiman, D., Lewis, L.H., Harris, V.G.: Magnetic and structural properties of heat-treated high-moment mechanically alloyed MnAlC powders. J. Alloys Compd. 582, 598–602 (2014)CrossRefGoogle Scholar
  13. 13.
    Lu, W., Niu, J., Wang, T., Xia, K., Xiang, Z., Song, Y., Mi, Z., Zhang, W., Tian, W., Yan, Y.: Phase transformations kinetics and microstructural evolutions of MnAl permanent magnet alloys. J. Alloys Compd. 685, 992–996 (2016)CrossRefGoogle Scholar
  14. 14.
    Liu, Z.W., Chen, C., Zheng, Z.G., Tan, B.H., Ramanujan, R.V.: Phase transitions and hard magnetic properties for rapidly solidified MnAl alloys doped with C, B, and rare earth elements. J. Mater. Sci. 47, 2333–2338 (2012)ADSCrossRefGoogle Scholar
  15. 15.
    Nouri, A., Wen, C.: Surfactants in mechanical alloying/milling: a catch-22 situation. Crit. Rev. Sol. Stat. Mater. Sci. 39, 81–108 (2014)ADSCrossRefGoogle Scholar
  16. 16.
    Saravanan, P., Vinod, V.T.P., Cernik, M., Chakravarty, D., Ghosal, P., Kamat, S.V.: Exchange coupled rare-earth free Mn-Al/Fe nanocomposite magnets by spark plasma sintering. Mater. Lett. 137, 369–372 (2014)CrossRefGoogle Scholar
  17. 17.
    Chuev, M.A., Hesse, J.: Nanomagnetism: extension of the Stoner-Wohlfarth model within Néel’s ideas and useful plots. J. Phys.: Condens. Matter. 19, 506201 (2007)Google Scholar
  18. 18.
    Cui, B.Z., Zheng, L.Y., Li, W.F., Liu, J.F., Hadjipanayis, G.C.: Single-crystal and textured polycrystalline Nd2Fe14B flakes with a submicron or nanosize thickness. Acta Mater. 60, 1721–1730 (2012)CrossRefGoogle Scholar
  19. 19.
    Agudelo, A.C., Marco, J.F., Gancedo, J.R., Perez Alcazar, G.A.: Fe-Mn-Al-C alloys: a study of their corrosion behaviour in SO2 environments. Hyperfine Interact. 139/140, 141 (2002)CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2018

Authors and Affiliations

  • J. S. Trujillo Hernandez
    • 1
    • 2
  • F. Maccari
    • 3
  • L. G. Marshall
    • 4
  • Jesús A. Tabares
    • 1
  • G. A. Pérez Alcázar
    • 1
  1. 1.Departamento de FísicaUniversidad del ValleMélendezColombia
  2. 2.Facultad de Ciencias Naturales y MatemáticasUniversidad de IbaguéIbaguéColombia
  3. 3.Institute of Materials ScienceTechnische Universitaet DarmstadtDarmstadtGermany
  4. 4.Department of Chemical EngineeringNortheastern UniversityBostonUSA

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