Inelastic neutron scattering study of the spin dynamics in the YBa2Cu3O6+χ system

✍ Scribed by J. Rossat-Mignod; L.P. Regnault; P. Bourges; P. Burlet; C. Vettier; J.Y. Henry

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 849 KB
• Volume: 192
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/0921-4526(93)90113-k

✦ Synopsis

Inelastic neutron scattering experiments have been carried out on YBa2Cu306÷ x single crystals in order to perform a systematic investigation of the spin dynamics in the various typical regimes: the pure and doped AF-states (x = 0,15, 0.37), the weakly doped (x = 0.45, 0.51), the heavily doped (x = 0.69, 0.92) and the overdoped (x = 1) metallic states. In the insulating state, the hole doping strongly affects the AF-order and yields a strong renormalization of the spin wave velocity. In the metallic state, dynamical AF-correlations remain, but the in-plane correlation length becomes very short (~/a = 0.8) as the doping increases. However, the AF-coupling between the two CuO2-1ayers is not affected, except in the overdoped regime. At low temperatures the spin excitation spectrum exhibits an energy gap in any superconducting samples. Its value, Eo/kT c =3.5, becomes much weaker close to the I-M transition. Moreover, a pseudo-gap persists above T c in the heavily doped regime.