  Polarized elastic neutron scattering measurements have been performed in the
bilayer copper oxide system Bi2Sr2CaCu2O8+d, providing evidence for an intra
unit cell (IUC) magnetic order inside the pseudo-gap state. That shows time
reversal symmetry breaking in that state as already reported in Bi2Sr2CaCu2O8+d
through dichroism in circularly polarized photoemission experiments. The
magnetic order displays the same characteristic features as the one previously
reported for monolayer HgBa2CuO4+d and bilayer YBa2Cu3O6+x, demonstrating that
this genuine phase is ubiquitous of the pseudo-gap of high temperature copper
oxide materials.
