Two-Dimensional (2D) magnetic crystals are for all intents and purposes almost totally new entities. The physics of those objects is original, with open questions related to the qualitative changes in magnetic behavior observed while changing the number of layers, the anisotropy requirements for the magnetic order to overcome thermal fluctuations, the conditions required to maximize the transition temperature, etc. An innovative research route to explore low dimensional physics has recently been opened by the discovery of a novel system: magnetically-ordered Rare Earth (RE) MAX phases. MAX phases form a family of nano- lamellar materials where M is usually restricted to an early transition metal, A is an A-group element and x=C or N. They offer a unique combination of ceramic and metallic-like properties, stemming from their inherently nano-laminated atomic structure. Adding ordered RE elements and magnetic characteristics open new potentialities, from spintronics to refrigeration, even though the research efforts have so far been focused solely on the discovery of new magnetic phases and compositions and fundamentals of magnetic properties.

The great advantage of RE-based MAX phases lies in the fact that the local environment can easily be tuned just by a change in the RE element, which, in turn, should allow us to shed important light on many intriguing and fascinating interrogations. Crystals of those nano-lamellar carbides can be exfoliated. If 2D ferromagnetic single sheets are produced, such a major breakthrough can lead to spin injection and/or detection and pave the way for applications in the field of spin electronics and quantum computing.

The PhD topic focuses on deciphering the magnetic properties of Re-i-MAX phases with Mo4RE4Al7C3 or Mo4RE2Al3C3 composition. Our goal is to use the ferromagnetism of the periodic lattice of the RE atoms to induce spin polarization of the 2D free electrons at the Fermi level, which are located within the Mo atom planes. The key issue is then to probe the magnetic properties of Mo and RE atoms separately using synchrotron-based X-ray spectroscopies like X-ray Magnetic Circular Dichroism (XMCD), developed at the ESRF beam line ID12. The group in Grenoble is the only lab in the world growing macroscopic single crystals of MAX phases, and was already successful in producing mm-sized single crystals of four of the phases initially discovered in powder form at Linköping University (LiU). Main objectives of the PhD are (i) to grow sizeable, high quality single crystals, (ii) to establish structure-property relationships through a wide variety of characterization techniques (TEM, SQUID, magneto-transport measurements) and (iii) to study the electronic and magnetic properties of each RE-MAX phase element selectively. The PhD project is co-funded by the IDEX ISP program and by ESRF on equal basis. It will allow us to leverage the expertise of each partner in order to produce pioneering, high impact science on this exciting, new family of 2D solids.