Theoretical study on the exchange constants of the transition metal systems

Heisenberg type exchange constants of the 3d transition metals are theoretically studied based both on the Hubbard model and the first principles calculations with the local spin density functional approach. Investigations from these two approaches convince ourselves that the exchange constants of the 3d transition metals can be explained mainly through the differences of the d electron concentration and is insensitive to the details of the band structures. Quantitatively, the exchange constants calculated with first principles approach reproduce well the trend of the measured magnetic transition temperatures of the transition metals.