Recent experiments showed that Co undergoes a phase transition from ferromagnetic hcp phase to non-magnetic fcc one around 100 GPa. Since the transition is of first order, a certain region of co-existence of the two phases is present. By means of \textit{ab initio} calculations, we found that the hcp phase itself undergoes a series of electronic topological transitions (ETTs), which affects both elastic and magnetic properties of the material. Most importantly, we propose that the sequence of ETTs lead to the stabilisation of a non-collinear spin arrangement in highly compressed hcp Co. Details of this non-collinear magnetic state and the interatomic exchange parameters that are connected to it, are presented here.
@article{arxiv.1508.06602,
title = {Electronic topological transition and non-collinear magnetism in compressed hcp Co},
author = {Y. O. Kvashnin and W. Sun and I. Di Marco and O. Eriksson},
journal= {arXiv preprint arXiv:1508.06602},
year = {2015}
}