Paramagnetic spin correlations in colossal magnetoresistive La _0.7Ca _0.3MnO ₃

Neutron spectroscopy measurements reveal dynamic spin correlations throughout the Brillouin zone in the colossal magnetoresistive material La _0.7Ca _0.3MnO ₃ at 265 K (∼1.03 T _C). The long-wavelength behavior is consistent with spin diffusion, yet an additional and unexpected component of the scattering is also observed in low-energy constant-E measurements, which takes the form of ridges of strong quasielastic scattering running along (H 0 0) and equivalent directions. Well-defined Q-space correlations are observed in constant-E scans at energies up to at least 28 meV, suggesting robust short-range spin correlations in the paramagnetic phase.