Magnetic instabilities in ordered and disordered Invar systems

We performed total energy calculations for several transition metal systems showing Invar and anti-Invar anomalies using methods based on the LMTO technique. The sensibility of the magnetic properties against the number of valence electrons per atom and to external pressure has been analyzed and compared with experiment. The influence of substitutional disorder on the electronic properties of Ni-Fe and Fe-Cr is briefly discussed