Discovery and Implications of Hidden Atomic-Scale Structure in a Metallic Meteorite

Kovács, A. and Lewis, L.H. and Palanisamy, D. and Denneulin, T. and Schwedt, A. and Scott, E.R.D. and Gault, B. and Raabe, D. and Dunin-Borkowski, R.E. and Charilaou, M.

Volume: 21 Pages: 8135-8142
DOI: 10.1021/acs.nanolett.1c02573
Published: 2021

Iron and its alloys have made modern civilization possible, with metallic meteorites providing one of the human's earliest sources of usable iron as well as providing a window into our solar system's billion-year history. Here highest-resolution tools reveal the existence of a previously hidden FeNi nanophase within the extremely slowly cooled metallic meteorite NWA 6259. This new nanophase exists alongside Ni-poor and Ni-rich nanoprecipitates within a matrix of tetrataenite, the uniaxial, chemically ordered form of FeNi. The ferromagnetic nature of the nanoprecipitates combined with the antiferromagnetic character of the FeNi nanophases gives rise to a complex magnetic state that evolves dramatically with temperature. These observations extend and possibly alter our understanding of celestial metallurgy, provide new knowledge concerning the archetypal Fe-Ni phase diagram and supply new information for the development of new types of sustainable, technologically critical high-energy magnets. ©

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