  High-Tc copper oxides of the LSCO family show a very clear case of
competition between antiferromagnetic (AF) order and superconductivity.
Magnetic order can, however, coexist with superconductivity, and the
experimental evidence for frozen magnetic moments in superconducting samples is
reviewed here. The primary characteristics of the magnetic order are summarized
and some open questions are outlined, particularly concerning the intrinsic or
extrinsic nature of this order around x=0.12.
