Accounting for spin fluctuations beyond local spin density approximation in the density functional theory

We present a method to correct the magnetic properties of itinerant systems in the local-spin-density approximation (LSDA), and we apply it to the ferromagnetic-paramagnetic transition under pressure in a typical itinerant system Ni3Al. We obtain a scaling of the critical fluctuations as a function of pressure equivalent to the one obtained within Moryia's theory. Moreover, we show that in this material the role of the band structure is crucial in driving the transition. Finally, we calculate the magnetic moment as a function of pressure and find that it gives a scaling of the Curie temperature that is in good agreement with experiment. The method can be easily extended to the antiferromagnetic case and applied, for instance, to the Fe pnictides in order to correct the LSDA magnetic moment.