Modelling Atomic Ordering and Magnetocrystalline Anisotropy in L10 FeNi (Tetrataenite)
Date:
Contributed talk at the 2024 International Conference on Magnetism.
Abstract
In the face of ever-growing demand for permanent magnets for advanced applications, there is a pressing need for materials to be developed which will reduce humanity’s dependence on critical materials, including rare earth elements. This is because there are myriad concerns around these constrained materials, including price volatility, geopolitical sensitivities, and concerns around the environmental impact of their extraction. One rare-earth-free magnetic material of current interest is atomically ordered FeNi [1], which crystallizes in the L10 structure and is commonly referred to by its meteoritic mineral name, tetrataenite [2]. However, a low atomic ordering temperature and consequently sluggish kinetics make this material challenging to synthesize in the laboratory. Here, new results will be presented examining the combined impacts of mechanical strain and varying Fe:Ni ratio on the L10 ordering temperature of this material, which are in alignment with recent experimental results reporting bulk, lab-based synthesis of the L10 phase given suitable processing conditions [3]. Our DFT-based methodology [4,5] enables holistic modelling of both atomic ordering and associated magnetocrystalline anisotropy within the same computational framework. These results suggest new routes by which economically viable synthesis of this material could be achieved and are therefore of profound technological significance.
References
[1] L. Neel et al., J. Appl. Phys. 35, 873 (1964).
[2] L. H. Lewis et al., J. Phys.: Condens. Matter 26, 064213 (2014).
[3] L. H. Lewis, P. S. Stamenov, Adv. Sci. 2302696 (2023).
[4] C. D. Woodgate et al., J. Appl. Phys. 134, 163905 (2023).
[5] C. D. Woodgate et al., arXiv:2401.02809 (2024).