The resonant magnetic mode: A common feature of high-Tc superconductors

Inelastic neutron scattering experiments in high-Tc cuprates have evidenced a new magnetic excitation present in the superconducting state. In particular, recent experiments on single-layer Tl2Ba2CuO6+δ, performed near optimum doping (Tc ∼ 90 K), provide evidence of a sharp magnetic resonant mode below Tc, similar to previous reports on the YBCO and BSCCO bilayer systems. This result supports models that ascribe a key role to magnetic excitations in the mechanism of superconductivity.