EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

High-performance permanent magnets are needed for a large number of applications, especially ‘green’ energy conversion, such as electric motors and windmills, which require them in extremely large quantities. At the same time, the heavier rare-earth elements which are necessary for obtaining the good magnetic characteristics of these materials are often mined with methods that leave an environmental footprint, quite expensive, and are rapidly decreasing in availability.
We are using a high-throughput and data-mining approach to the search of rare-earth free permanent magnets by filtering through a large number of known structures from ICSD database [1] looking for the materials with high M >1 T, uniaxial MAE >1 MJ/m3, and Tc >300 K.
A search was performed for the materials that contain at least two 3d- metals. A new material was found (that had not been used as a permanent magnet before) and consequently synthesized – Co3Mn2Ge [4]. From the ab-initio theory, the defect-free material is predicted to have the saturation magnetization of 1.71 T, the uniaxial magnetocrystalline anisotropy of 1.44 MJ/m3, and the Curie temperature of 700 K. The samples synthesized were found to have a partial disorder of Co and Ge. 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 TC = 359 K. These magnetic properties make Co3Mn2Ge a very promising material to be considered 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 would like to acknowledge the financial support of the SSF and SNIC for the computation resources.