NEW DYNAMICAL FEATURES IN LA0.95CA0.05MNO(3)

Inelastic neutron scattering data of La0.95Ca0.05MnO3 are reported and compared to those of LaMnO3. At this low doping rate, the energy spec tra are drastically changed. Around all ferromagnetic centers, a new m agnetic mode appears which is very weakly dispersed. It coexists with a dispersed spin-wave branch, similar to that found in the pure system , showing a strong decrease of interplane coupling. The new mode, whic h reveals a magnetic coupling of distinct origin, could be a precursor effect of the dynamics in the metallic state.