Observation of magnetic moments in the superconducting state of YBa2Cu3O6.6 - art. no. 012502

Neutron scattering measurements for YBa2Cu3O6.6 have identified small magne tic moments that increase in strength as the temperature is reduced below T * and further increase below T-c. An analysis of the data shows the moments are antiferromagnetic between the Cu-O planes with a correlation length of longer than 195 Angstrom in the a-b plane and about 35 Angstrom along the c axis. The origin of the moments is unknown, and their properties are disc ussed both in terms of Cu spin magnetism and orbital bond currents.