Rare earth free permanent magnets based on exchange coupling

The energy transition fosters the growth of the demand for electric machines, in particular for use in electric vehicles and in wind turbines. These electric machines rely on permanent (hard) magnets with high energy density. Therefore,  today mainly NdFeB alloys are used as magnets, since they are the most powerful magnets currently available. The use of rare earths (Nd and others) in these magnets poses a multitude of problems, with respect to the availability of resources, strong price fluctuations, and the geopolitical dependence on the countries detaining the resources (and the capability of refining them). There are two options to circumvent these problems: (i) build up a recycling industry for rare earths or (ii) use alternative magnets, which do not rely on rare earths. As such alternatives we can cite FeN12, alloys of Mn and hexaferrites (MFe12O19; M = Sr, Ba, etc.). 
This thesis project will focus on hexaferrites. Hexaferrites have been in commercial use for a long time, but they are handicapped by their low magnetization, leading to low energy density. On the other hand, Fe and Co or their alloys have a very high magnetization, but are soft magnets. Theory predicts that if a hard and a soft magnet are mixed on nanoscale, their magnetic properties get coupled (exchange coupling), which may render the soft component hard. Such a magnetically coupled nanocomposite is a very attractive design target, but the desired correct nanoscale architecture is difficult to build in practice. The goal of the PhD project is to develop efficient synthesis methods that approach the optimal nanostructured composites predicted by theory. It, therefore, combines the fields of chemistry (nanoparticle synthesis) and physics (characterization of the magnetic properties). State of the art characterization methods (including synchrotron experiments) will be used for monitoring the syntheses and analyzing the physico-chemical properties of the prepared nanocomposites, in order to understand and rationalize the physico-chemical mechanisms involved during the formation and the use of these nano-magnets.
The candidate should have experience in inorganic chemistry and an interest in the physics of magnetism, be rigorous, hard-working and have a passion for science. A good level in English (in speaking and writing) is required (and if applicable, the willingness to learn French). 

Keywords: permanent magnet, soft magnet, exchange coupling, nanoparticle synthesis 

• Academic supervisor    Prof. Frédéric MAZALEYRAT, ENS Paris-Saclay, ORCID : 0000-0001-8544-4599
• Doctoral School    Electrical Optical and Bio-Engineering (EOBE ED 375) Univ. Paris-Saclay
• IFPEN supervisor    Dr  Gerhard PIRNGRUBER, ORCID : 0000-0003-0688-425X.
• PhD location    IFPEN, Lyon, France  
• Duration and start date    3 years, starting in the fourth quarter 2026
• Employer    IFPEN
• Academic requirements    Master degree in Chemistry, Physics, Material Science   
• Language requirements    English level B2 (CEFR), Willingness to learn French    

    
To apply, please send your cover letter and CV to the IFPEN supervisor indicated here below.