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2021 (English)In: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 212, article id 116913Article in journal (Refereed) Published
Abstract [en]
A new class of rare-earth-free permanent magnets is proposed. The parent compound of this class is Co3Mn2Ge, and its discovery is the result of first principles theory combined with experimental synthesis and characterisation. The theory is based on a high-throughput/data-mining search among materials listed in the ICSD database. From ab-initio theory of the defect free material it is predicted that the saturation magnetization is 1.71 T, the uniaxial magnetocrystalline anisotropy is 1.44 MJ/m3, and the Curie temperature is 700 K. Co3Mn2Ge samples were then synthesized and characterised with respect to structure and magnetism. The crystal structure was found to be the MgZn2-type, with partial disorder of Co and Ge on the crystallographic lattice sites. From magnetization measurements a saturation polarization of 0.86 T at 10 K was detected, together with a uniaxial magnetocrystalline anisotropy constant of 1.18 MJ/m3, and the Curie temperature of TC = 359 K. These magnetic properties make Co3Mn2Ge a very promising material as a rare-earth free permanent magnet, and since we can demonstrate that magnetism depends critically on the amount of disorder of the Co and Ge atoms, a further improvement of the magnetism is possible. We demonstrate here that the class of compounds based on T3Mn2X (T = Co or alloys between Fe and Ni; X = Ge, Al or Ga) in the MgZn2 structure type, form a new class of rare-earth free permanent magnets with very promising performance.
Place, publisher, year, edition, pages
Elsevier, 2021
Keywords
Permanent magnets, Rare-earth, Synthesis, DFT, Magnetism
National Category
Condensed Matter Physics Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-448912 (URN)10.1016/j.actamat.2021.116913 (DOI)000663657100005 ()
Funder
VinnovaSwedish Foundation for Strategic Research SweGRIDS - Swedish Centre for Smart Grids and Energy StorageSwedish Energy AgencySwedish Research CouncilKnut and Alice Wallenberg FoundationStandUpSwedish National Infrastructure for Computing (SNIC)
2021-07-122021-07-122024-01-15Bibliographically approved