Raman scattering from spin fluctuations in the cuprates

Raman scattering experiments on cuprate materials, both insulating and metallic, have provided insights on the role of magnetic phenomena in the properties of these materials. Light scattering in fact provides the most convenient measure of the superexchange interaction in the insulating materials, where we find that modification of existing theories is required to obtain a quantitative description for the spin half case. In the metallic and superconducting materials we find evidence that short wavelength spin excitations coexist with the superconducting material.