Thermal Activation in Permanent Magnets

Abstract

The coercive field of permanent magnets decays with temperature. At non-zero temperatures, the system can overcome a finite energy barrier through thermal fluctuations. Using finite element micromagnetic simulations, we quantify this effect, which reduces coercivity in addition to the decrease of the coercive field associated with the temperature dependence of the anisotropy field, and validate the method through comparison with existing experimental data.

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Acknowledgements

This paper is based on results obtained from the future pioneering program “Development of magnetic material technology for high-efficiency motors” commissioned by the New Energy and Industrial Technology Development Organization (NEDO). The authors would like to acknowledge funding support from the Replacement and Original Magnet Engineering Options (ROMEO) Seventh Framework Program (FP7).

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Correspondence to S. Bance.

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Bance, S., Fischbacher, J., Kovacs, A. et al. Thermal Activation in Permanent Magnets. JOM 67, 1350–1356 (2015). https://doi.org/10.1007/s11837-015-1415-7

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Keywords

  • Domain Wall
  • Energy Barrier
  • Permanent Magnet
  • Coercive Field
  • Magnetization Reversal