Effects of zero-point spin fluctuation on the metamagnetism in YCo2 and LuCo2

Metamagnetism in YCo2 and LuCo2 is investigated in the spin-fluctuation the ory, considering the contribution from both the zero-point and the thermal spin fluctuation. The metamagnetic transition at low temperature and the te mperature dependence of the paramagnetic susceptibility at finite temperatu re are investigated in a self-consistent numerical calculation based on the spin-fluctuation theory and good agreements with experimental results have been obtained in a systematic way. It is shown that the effect of strong e nhancement of the paramagnetic susceptibility and the electronic specific c oefficient at low temperature can be explained satisfactorily by taking int o consideration the zero-point spin fluctuation.