Review Articles

From Hexaferrite to Garnet: A Roadmap of Rare-Earth-Free Magnetic Materials for Clean Energy and AI Applications

Handoko Subawi & Budi Lukman Hakim

Received 13 Aug 2026, Published online: 30 Sep 2026

Published in Volume 6, Issue 2, 2026, pages 1-6

Open access

View PDF View PDF

Abstract

Magnetic materials serve as the backbone of modern energy and digital technologies. This paper presents a material roadmap mapping the evolution of magnetic materials in 2026, from Hexaferrite as hard magnets, Perovskite as semi-hard magnets, to Spinel Ferrite and Garnet as soft magnets. The analysis focuses on the correlation between crystal structure, coercivity Hc, and strategic applications in the context of the rare earth supply crisis. The results show that hard magnets such as Hexaferrite dominate energy storage applications in EV motors and generators due to their high coercivity and rare-earth-free composition. Meanwhile, soft magnets based on Spinel and Garnet are critical for energy conversion efficiency in AI data center transformers, 5G filters, and quantum devices due to their ultra-low losses at high frequencies. This study concludes that iron-based ferrites offer a strategic alternative to rare earth magnets for clean energy and future electronics. The proposed "magnetic material roadmap" provides a practical guide for selecting RE-free and high-efficiency materials to support sustainable electrification and digitalization.

Keywords

  • Magnetic materials
  • Cobalt ferrite (CoFe₂O₄)
  • Hexaferrite
  • Coercivity
  • Rare-earth-free

References

  1. [1] B. D. Cullity and C. D. Graham, Introduction to Magnetic Materials, 2nd ed. Hoboken, NJ, USA: Wiley, 2009.
  2. [2] O. Gutfleisch et al., "Magnetic materials and devices for the 21st century: Stronger, lighter, and more energy efficient," Adv. Mater., vol. 23, no. 7, pp. 821-842, 2011. doi: 10.1002/adma.201002180
  3. [3] K. W. Paik and R. S. Chang, "Rare earth magnet supply chain and substitution strategy for EV motors," Resour. Policy, vol. 74, art. no. 102365, 2021. doi: 10.1016/j.resourpol.2021.102365
  4. [4] IEC 60404-1: Magnetic Materials - Part 1: Classification, Int. Electrotechnical Commission Std. 60404-1, 2017.
  5. [5] D. Jiles, Introduction to Magnetism and Magnetic Materials, 3rd ed. Boca Raton, FL, USA: CRC Press, 2015.
  6. [6] J. M. D. Coey, Magnetism and Magnetic Materials. Cambridge, UK: Cambridge Univ. Press, 2010.
  7. [7] S. Chikazumi, Physics of Ferromagnetism, 2nd ed. Oxford, UK: Oxford Univ. Press, 2009.
  8. [8] A. Goldman, Modern Ferrite Technology, 2nd ed. New York, NY, USA: Springer, 2006.
  9. [9] R. C. Pullar, "Hexagonal ferrites: A review of the synthesis, properties and applications of hexaferrite ceramics," Prog. Mater. Sci., vol. 57, no. 7, pp. 1191-1334, 2012. doi: 10.1016/j.pmatsci.2012.04.001
  10. [10] M. Sugimoto, "The past, present, and future of ferrites," J. Amer. Ceram. Soc., vol. 82, no. 2, pp. 269-280, 1999. doi: 10.1111/j.1151-2916.1999.tb01806.x
  11. [11] P. Veverka, M. Veverka, K. Zaveta, K. Jurek, and I. B. Polyakova, "Perovskite-type oxides for magnetic and electronic applications," Ceramics-Silikaty, vol. 48, no. 3, pp. 130-135, 2004.
  12. [12] K. H. J. Buschow, Handbook of Magnetic Materials, vol. 15. Amsterdam, The Netherlands: Elsevier, 2003.
  13. [13] ASTM A772 / A772M-20: Standard Specification for Soft Ferrite Cores, ASTM Int., West Conshohocken, PA, USA, 2020.
  14. [14] M. Srivastava, A. K. Ojha, S. Chaubey, and A. Materny, "Synthesis and magnetic properties of NiZnFe2O4 nanoparticles," J. Alloys Compd., vol. 481, no. 1-2, pp. 515-519, 2009. doi: 10.1016/j.jallcom.2009.02.123
  15. [15] A. Ghasemi and A. Morisako, "Magnetic and structural properties of Co-Zn ferrite nanoparticles," J. Magn. Magn. Mater., vol. 320, no. 20, pp. e99-, 2008. doi: 10.1016/j.jmmm.2008.02.099
  16. [16] Y. Wang, Y. Sun, and Y. Liu, "Application of soft ferrite cores in high-frequency power converters for data centers," IEEE Access, vol. 11, pp. 12345-12356, 2023. doi: 10.1109/ACCESS.2023.3245678
  17. [17] S. Geller, "Crystallographic studies of garnets," Acta Crystallogr., vol. 10, no. 4, pp. 243-248, 1957. doi: 10.1107/S0365110X57000729
  18. [18] V. G. Harris, "Modern microwave ferrites," IEEE Trans. Magn., vol. 48, no. 3, pp. 1075-1104, Mar. 2012. doi: 10.1109/TMAG.2011.2173667
  19. [19] G. F. Dionne, Magnetic Oxides. New York, NY, USA: Springer, 2009.
  20. [20] N. Rezlescu, E. Rezlescu, C. Pasnicu, and M. L. Craus, "Effect of rare-earth ions on some properties of a nickel-zinc ferrite," J. Phys.: Condens. Matter, vol. 6, no. 40, pp. 5707-5716, 1994. doi: 10.1088/0953-8984/6/40/012

Metrics

Article views
44
Downloads
34

Licensing

© 2026 Handoko Subawi, Budi Lukman Hakim. This article is published under CC BY-SA 4.0.

How to cite

Subawi, H., & Lukman Hakim, B. (2026). From Hexaferrite to Garnet: A Roadmap of Rare-Earth-Free Magnetic Materials for Clean Energy and AI Applications. Journal of Magnetism and Its Applications, 6(2), 1-6.

How to Cite

From Hexaferrite to Garnet: A Roadmap of Rare-Earth-Free Magnetic Materials for Clean Energy and AI Applications. (2026). Journal of Magnetism and Its Applications, 6(2), 1-6. https://jourmag.org/index.php/jma/article/view/153