First principles calculations of the itinerant magnetism of cubic laves phase compounds

摘要: [en] The cubic Laves phase compounds YFe 2, ZrFe 2, YCo 2, ZrCo 2 exhibit different magnetic properties. YFe 2 and ZrFe 2 order magnetically. For these four compounds self consistent spin polarised energy band calculations were performed by means of th Augmented Spherical Wave (ASW) method. It is important to know the magnetic free energy as a function of magnetisation. The newly developed Fixed Spin Moment (FSM) method allows to obtain the complete functional dependence of the free energy including excited magnetic states. YFe 2 and ZrFe 2 were found ferrimagnetically. The origin of the ferrimagnetic coupling could be explained in terms of the covalent magnetism. At the theoretical equilibrium lattice constant YCo 2 is a paramagnet, but at a slightly increased volume a metamagnetic transition could occur. The critical field for this transition can be estimated from the shape of the free energy function to be at least 300T. ZrCo 2 remains paramagnetic. For these compounds the theoretical results are in very good agreement with the experimental data and provide an understanding of their magnetic properties. It can be expected that these results are of interest for the whole class of Laves phases.(Author)