Toward cost-competitive Fe2P permanent magnets

Context

Permanent magnets are indispensable components of our modern technology. The permanent magnets market is currently divided between the low-performance yet inexpensive ferrites and the high performance but critical rare-earth compounds. The development of cost-competitive intermediate products is of interest, with these products being based on elements that are widely available, such as iron (Fe) and phosphorus (P).

The Fe₂P-type structure consists of non-equivalent metallic sites stacked along the c-axis of the hexagonal lattice. This quasi-2D structure exhibits a large uniaxial magneto-crystalline anisotropy, which is one of the prerequisites for permanent magnets. Recent investigations have shown that subtle chemical compounding can lead to a combination of intrinsic properties (saturation magnetization, Curie temperature and uniaxial anisotropy) promising for applications.

Project

At an early stage of research, a plethora of questions regarding Fe₂P magnets remain unanswered. First, in order to define the most promising compounding strategies, a systematic exploration of the phase diagrams of quaternary (Fe,TM)₂(P,Si) compounds with TM denoting a transition metal is required. A focus of the project is to gain a deeper understanding of the structure-properties relationships. For that purpose, preliminary investigations on polycrystalline samples will be complemented by accurate magnetic anisotropy measurements on single crystals. In addition, preferential site occupancies will be addressed by experiments at large-scale facilities (e.g. x-ray absorption).

The development of permanent magnets is not contingent upon the optimization of intrinsic properties alone; it is also dependent upon a precise control of the microstructure. To enhance the coercivity, it is therefore imperative to optimize the current synthesis method, which involves a sequence of ball-milling and solid-state reaction. In addition, unconventional sintering methods such as based on Spark Plasma Sintering will have to be explored.

CRISMAT (Laboratoire de CRIstallographie et Sciences des MATériaux – Caen): A leading materials science laboratory specializing in the synthesis, characterization, and modeling of advanced materials.

We are seeking a highly motivated and talented experimentalist with a Master's degree in Materials Science, Physics, Chemistry, or a related field. A familiarity with intermetallic synthesis methods (ball-milling, arc-melting, mel-spinning or similar methods), microscopy, X-ray diffraction techniques and/or magnetic measurements is a plus. A good level in written and spoken English is also expected.