Paramagnetic spin correlations in colossal magnetoresistive La0.7Ca0.3MnO3

Neutron spectroscopy measurements reveal dynamic spin correlations throughout the Brillouin zone in the colossal magnetoresistive material La${}_{0.7}$Ca${}_{0.3}$MnO${}_{3}$ at 265 K ($\ensuremath{\approx}1.03$ ${T}_{C}$). 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.