Rare earth high performance magnets for energy applications: Demand, sustainability and the reality of alternatives

Magnetic materials are key components in energy technologies, robotics, sensors and information technology. Magnets are inseparable from our everyday life. “Green” energy technologies such as wind turbines, electro-mobility and solid state cooling, rely on high performance magnetic materials which have to be available in bulk quantities, at low-cost and with tailored magnetic hysteresis.
The realisation of renewable energy technologies is generally linked to the sustainable availability of strategic metals such as the group of rare earth elements (REE) namely Nd, Gd, Tb, Dy, transition metals such as Co, Ga, Ge, In, and the platinum group metals. Resource criticality is understood here as a concept to assess potentials and risks in using raw materials and their functionality in emerging technologies. Specifically, the demand, sustainability and the reality of alternatives of rare earth elements will be discussed.
There is an ever-growing demand for the benchmark high performance Nd-Fe-B magnets. The increase in e-mobility and wind energy and other smart magnet usages in the future has yet to have its impact on the rare earth market. No substitute is at hand for the massive amounts of high-energy density magnets needed; yet various concept of heavy rare earth free, free rare earth and rare earth free magnets are being explored.
Gas-vapour compression technology for refrigeration, heating, ventilation, and air-conditioning has remained unchallenged for more than 150 years. There is a huge demand for a smarter, more flexible and more efficient cooling technology. Magnetic refrigeration could be that alternative working without gas-based refrigerants. Energy spent for domestic cooling is expected to outreach that for heating worldwide over the course of the twenty-first century.
I will address these different global trends and will attempt to scale bridge these challenges by discussing the modelling, synthesis, characterization, and property evaluation of novel magnetic materials considering their micromagnetic length scales, phase transition characteristics and hysteretic properties.
[1] O. Gutfleisch, M. A. Willard, E. Brück, C. H. Chen, S. G. Sankar, and J. P. Liu, Magnetic materials and devices for the 21st century: stronger, lighter, and more energy efficient. Adv. Mater. 23 (2011) 82.
[2] K.P. Skokov and O. Gutfleisch, Heavy rare earth free, free rare earth and rare earth free magnets - vision and reality, Scripta Materialia View Point Set, 154 (2018) 289-294.
[3] T. Gottschall, A. Gracia-Condal, M. Fries, A. Taubel, L. Pfeuffer, L. Manosa, A. Planes, K.P. Skokov, O. Gutfleisch, A multicaloric cooling cycle that exploits thermal hysteresis, Nature Materials, accepted.
[4] M. Duerrschnabel, M. Yi, K. Uestuener, M. Liesegang, M. Katter, H.-J. Kleebe, B. Xu, O. Gutfleisch, L. Molina-Luna, Atomic structure and domain wall pinning in samarium -cobalt based permanent magnets, Nature Communications 8:54 (2017).
[5] J. Liu, T. Gottschall, K.P. Skokov, J.D. Moore, O. Gutfleisch, Giant magnetocaloric effect driven by structural transition, Nature Mat. 11 (2012) 620.

Bio:
Prof. Oliver Gutfleisch is a full Professor (W3) for Functional Materials at TU Darmstadt and a scientific manager at Fraunhofer IWKS Materials Recycling and Resource Strategies. He studied Material Science at TU Berlin, did his PhD in Birmingham, UK, and was a group leader at Leibniz Institute IFW Dresden. 2012 he joined TU Darmstadt. His scientific interests span from new permanent magnets for power applications to solid state energy efficient magnetic cooling, ferromagnetic shape memory alloys, magnetic nanoparticles for biomedical applications, and to solid state hydrogen storage materials with a particular emphasis on tailoring structural and chemical properties on the nanoscale. Resource efficiency on element, process and product levels as well as recycling of rare earth containing materials are also in the focus of his work.
He has published more than 370 papers in refereed journals, and has given more than 210 invited talks. In 2011 he was an IEEE Magnetics Society Distinguished Lecturer on the topic of Magnet Materials for Energy. He is on the Intl. Advisory Committees of JEMS, of the Int. Workshop on Rare Earth Permanent Magnets and their Applications and of the Magnetic Refrigeration Intl. Working Party, and of the TMS Magnetic Materials Committee. He served on the IEEE Magnetics Society AdCom (2011-2013). He is EU ERAMIN (Network on the Industrial Handling of Raw Materials for European Industries) advisor on substitution, a member of the EU ERECON (European Rare Earths Competency Network) Steering Committee and chairs the DGM Fachausschuss Functional Materials. He did hold visiting Professorships at Imperial College London and Chinese Academy of Science NIMTE Institute in Ningbo and from autumn 2017 he is a visiting Professor at University of Parma. In April 2017 he was awarded an ERC Advanced Grant (Cool Innov) and he will receive the Prize of the German Materials Society (DGM Prize 2018).