Dresden 2017 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 56: Bulk Materials: Soft and hard permanent magnets
MA 56.1: Vortrag
Donnerstag, 23. März 2017, 15:00–15:15, HSZ 403
Ab initio theory of Fe-based permanent magnets — •Olga Vekilova, Olle Eriksson, and Heike Herper — Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden
Strong permanent magnets are of great importance for many technological applications, from magnetic resonance imaging to green sources of energy. The modern society is currently interested in the design of magnetic materials that are cheaper and contain smaller amounts of rare earth elements compared with the existing ones. Theoretical modelling is a promising tool to discover new advanced rare earth-free permanent magnets. Good permanent magnet is a ferromagnetic compound with high Curie temperature, high saturation magnetization and high anisotropy energy. The latter is the key factor for the required large coercivity and in addition it should be uniaxial. The listed conditions are satisfied in Fe-rich materials, in particular in hexagonal Fe3Sn. However, as it is known from both the experiment and the theory, the easy magnetization axis lies in the hexagonal plane. One of the possibilities for changing the easy axis direction is through alloying. We have studied the magnetic properties of Fe-based alloys with phase stabilizers, such as Sn, Sb, Ga, Ge and Si to find new ferromagnetic phases with uniaxial anisotropy suitable for the development of advanced permanent magnets. The calculated magnetocrystalline anisotropies and Curie temperatures of these compounds are analyzed and suggestions for the better permanent magnets are formulated. The work is supported by NOVAMAG (EU686056)