In search for magnon-magnon/phonon coupling in metallic triangular antiferromagnet CrB2

Recent theories and experiments on two-dimensional triangular lattice antiferromagnet show that the spin dynamics of these system exhibit the rare phenomena due to high-order magnon interaction terms. This unuusal interaction can give rise to a so-called Roton-like minimum at the B point in the momentum space, a flat mode and finally a magnon breakdown. All these three key theoretical observations have now been borne out by our experiments, done at ISIS. With this sucess, we now want to study a metallic version of the same system. The question here is how the high-order term survies under the sea of condunction electron, in particular with the long-range RKKY interaction. For this study, we propose to investigate CrB2, a metallic triangular antiferromagnetic with TN=88 K and an incommensurate cycloid magnetic order.