Spin Dynamics in Heusler Alloy Pd2MnSn

The dynamical spin susceptibility in the ferromagnetic Heusler alloy X 2 MnY (Pd 2 MnSn) is evaluated on the basis of the realistic band structure. The theoretical results of spin wave spectra of Pd 2 MnSn are in good agreement with the experimental ones, as have been for Cu 2 MnAl. The correlation between the spin densities of d-electrons of Mn is important to the spin waves with small and large q in both Cu 2 MnAl and Pd 2 MnSn. In Pd 2 MnSn the correlation between the spin density of d-electrons of Mn and that of conduction electrons is important for the spin waves with small and large q , but in Cu 2 MnAl this correlation decreases significantly for those with large q . These different q dependences of the spin-density correlation for Cu 2 MnAl and Pd 2 MnSn are consistent with the strong dependence on X atom of the magnetic interactions pointed out by Ishikawa et al.