Scaling of spin-wave stiffness constant to Curie temperature in the colossal magnetoresistance material La1-xSrxMnO3

The spin dynamics of La1-xSrxMnO3 for Sr concentrations of x less than or equal to 0.3 were studied by inelastic neutron scattering. For the entire concentration range studied, we found that the spin-wave stiffness constant D and the paramagnetic spin-diffusion constant A* are ruled by the nearest neighbor interaction, i.e., the strength of double exchange interactions. The Sr concentration dependence of both the constants, D and A*, scale that of the Curie temperature T-C very well, and the ratios T-CMF/T-C (T-CMF: Mean field T-C determined from D) and A*/T-C fit in the universal table for typical transition metal ferromagnets.