Electronic structure and magnetic properties of YM2compounds (M=Mn, Fe, Co and Ni)

Abstract

The electronic structures of itinerant de electrons in the intermetallic compounds YMn₂, YFe₂, YCo₂ and YNi₂ with cubic Laves-phase structure are calculated using both the recursion method and the standard method of the tight-binding approximation (TBA). Using the calculated density-of-states curves in the TBA and taking the effect of spin fluctuations into account, the temperature dependences of the paramagnetic spin susceptibility in these compounds are calculated. The field dependence of the induced magnetic moment in YCo₂ at OK is also calculated. Good agreement between the calculated and observed results can be obtained by allowing the number of d electrons to be an adjustable parameter. Furthermore, the densities of states for magnetised YCo₂ and ferromagnetic YFe₂ are calculated. It is shown that the values of the local magnetic moments on Co and Fe are smaller than those in pure metals and the local magnetic moments on Y become negative due to the hybridisation between the d bands of Y and Co or Fe.