Magnetic and Charge Fluctuations in High-$T_c$ Superconductors
  Neutron scattering has been used to study the spin fluctuations in the YBa$_2$Cu$_3$O$_{7-x}$ and Bi$_2$Sr$_2$CaCu$_2$O$_8$ materials. Evidence is found for both incommensurate fluctuations and a commensurate resonance excitation. Measurements on the lattice dynamics for YBa$_2$Cu$_3$O$_{6.6}$ show incommensurate structure that appears to stem from charge fluctuations that are associated with the spin fluctuations. 
H. A. Mook, F. Dogan, and B. C. Chakoumakos