Tuesday 4 June, 13.30
Old Library, All Souls
Rare Earths, Meteorites and Magnets
Prof. Lindsay Greer, Cambridge
Rare-earth elements are not necessarily rare, but are found only in low-concentration deposits and are difficult to extract. They are used (at low concentrations) in many technologies: flat-panel displays, LED lights, camera lenses, catalytic converters, disc-drives, batteries, and many more. Now, the largest use is in permanent magnets, which are used in electric motors and generators. With the aim towards ‘zero carbon’ and electrification, manifest in the proliferation of electric cars and wind turbines, the demand for permanent magnets has soared. With up to 95% of all rare earths coming from China, there is strategic concern about security of supply: rare earths top the ‘critical materials’ list. It has been of great interest, therefore, that some meteorites (composed mainly of iron and nickel, and, importantly, devoid of rare earths) have regions within them with excellent magnetic properties, even rivalling those of man-made magnets containing rare earths. These regions even act as magnetic recorders of conditions in the early Universe. But meteorites cannot meet the demand for magnets. This talk is largely about the decades-long struggle to replicate the desirable structures in meteorites — a tale of occasional glimpses of success, of dashed hopes, and of ongoing efforts. And I will mention how I got into research in this area, while looking for something totally different!
Lindsay Greer earned MA and PhD degrees at Cambridge, then undertook postdoctoral work and was Assistant Professor of Applied Physics at Harvard University before returning to a faculty position in Cambridge. He has held visiting positions at the Institut National Polytechnique de Grenoble and the Centre d'Études Nucléaires de Grenoble, and was Harrison Distinguished Visiting Professor, Department of Physics and Centre for Materials Innovation, Washington University. He holds an Advisory Professorship at Chongqing University. He is an editor of Philosophical Magazine (founded in 1798, publishing papers on the structure and properties of condensed matter). He has been awarded the Pilkington Teaching Prize of the University of Cambridge, the Light Metals and Cast Shop Technology Awards of TMS (USA), the Cook-Ablett Award, the Hume Rothery Prize and the Griffith Medal of the Institute of Materials, Minerals and Mining, the ISMANAM Senior Scientist Medal, the Honda Kotaro Memorial Medal of Tohoku University, and the Lee Hsun Lecture Award of the Chinese Academy of Sciences. He has published two books, more than 10 book chapters and more than 350 scientific papers.
Seminars at 13.30, Old Library, All Souls
All are welcome, no need to book.
