Evidence for Intra-Unit Cell Magnetism in Superconducting Cuprates: a Technical Assessment

Intra unit cell (IUC) magnetic order observed by polarized neutron diffraction (PND) is one of the hallmarks of the pseudogap state of high-temperature copper oxide superconductors. This experimental observation, usually interpreted as a result of loop currents, has been recently challenged based on lower statistics data. We here address the crucial issue of polarization inhomogeneities in the neutron beams showing that the original data had a much better reproducibilty. Within these technical limitations, we here propose a self-consistent analysis that potentially solves the controversy. We show that all the reported PND experiments in superconducting cuprates are actually compatible with the existence of an IUC magnetism. (paper)