  Neutron scattering studies on a single crystal of the highly-correlated
electron system, La1-xSrxMnO3 with x~0.3, have been carried out elucidating
both the spin and lattice dynamics of this metallic ferromagnet. We report a
large measured value of the spin wave stiffness constant, which directly shows
that the electron transfer energy of the d band is large. The spin dynamics,
including magnetic critical scattering, demonstrate that this material behaves
similar to other typical metallic ferromagnets such as Fe or Ni. The crystal
structure is rhombohedral, as previously reported, for all temperatures studied
(below ~425K). We have observed new superlattice peaks which show that the
primary rhombohedral lattice distortion arises from oxygen octahedra rotations
resulting in an R-3c structure. The superlattice reflection intensities which
are very sensitive to structural changes are independent of temperature
demonstrating that there is no primary lattice distortion anomaly at the
magnetic transition temperature, Tc = 378.1 K, however there is a lattice
contraction.
