Dynamical Interplay between Coexisting Orders in the Electron-Doped   Cuprate Superconductor Nd_{2-x}Ce_xCuO_4
  We use coherent pump-probe spectroscopy to measure the photoinduced reflectivity \DeltaR, and complex dielectric function, {\delta}\in, of the electron-doped cuprate superconductor Nd_{2-x}Ce_xCuO_{4+\delta} at a value of x near optimal doping, as a function of time, temperature, and laser fluence. We observe the onset of a negative \DeltaR at T=85 K, above the superconducting transition temperature, T_c, of 23 K, that exhibits a form of scaling consistent with critical fluctuations in the time domain. A positive \Delta R onsets at T_c that we associate with superconducting order. We find that the two signals are strongly coupled below T_c, in a manner that suggests a repulsive interaction between superconductivity and antiferromagnetic correlations. 
J. P. Hinton, J. D. Koralek, G. Yu, E. M. Motoyama, Y. M. Lu, A.   Vishwanath, M. Greven, and J. Orenstein
cond-mat.supr-con