Nearly singular magnetic fluctuations in the normal state of a high-Tc cuprate superconductor
Polarized and unpolarized neutron scattering was used to measure the wave vector- and frequency-dependent magnetic fluctuations in the normal state (from the superconducting transition temperature, Tc = 35 kelvin, up to 350 kelvin) of single crystals of La1.86Sr0.14CuO4. The peaks that dominate the fluctuations have amplitudes that decrease as T-2 and widths that increase in proportion to the thermal energy, kBT (where kB is Boltzmann's constant), and energy transfer added in quadrature. The nearly singular fluctuations are consistent with a nearby quantum critical point.
Aeppli
G
G. Aeppli, NEC Research Institute, 4 Independence Way, Princeton, NJ 08540, USA, and Riso National Laboratory, 4000 Roskilde, Denmark. T. E. Mason, Department of Physics, University of Toronto, Toronto, Canada, M5S 1A7 and Riso National Laboratory,
Mason
TE
Hayden
SM
Mook
HA
Kulda
J