Neutron scattering study on Zn-doped YBa 2Cu 3O 6+ y system

Abstract

Neutron scattering studies on a c-axis polarized B 2u phonon and magnetic excitations of the YBa 2Cu 3− x Zn x O 6+ y system were carried out. For YBa 2Cu 2.9Zn 0.1O 6.75, anomalies of the B 2u mode related to the spin (pseudo) gap formation are insensitive to the Zn-doping. In the magnetic excitation spectra of YBa 2Cu 3O 6+ y samples which are close to the metal–insulator phase boundary, a gap-like structure can be seen at high temperatures, while at low temperatures the low energy spectral weights increase and the gap-like structure disappears. This suggests that the itinerant nature has an important role in the spin gap formation.