Magnetic coherence as a universal feature of cuprate superconductors

We extend our previous work on the magnetic coherence effect in La2-xSrxCuO 4 in which it was shown that the effect arises from the interplay of an inc ommensurate magnetic response, the form of the underlying Fermi surface, an d the opening of the d-wave gap in the fermionic spectrum. We present predi ctions for the magnetic coherence effect in parts of the magnetic Brillouin zone so far unexplored by inelastic neutron scattering (INS) experiments i ncluding parts where the so-called spin gap vanishes. We calculate the magn etic coherence effect expected in the superconducting state of YBa2Cu3O6+x, and make derailed predictions for its frequency and momentum dependence. T o the extent that our predictions are confirmed by future experiments, our work will demonstrate that INS experiments are riot confined to providing i nformation on the magnetic excitation spec trum, but can also probe the ele ctronic spectrum in the superconducting state.