MAGNETISM AND SUPERCONDUCTIVITY IN THE CHEVREL-PHASE HOMO6S8

We summarise the results of a neutron scattering study of the magnetic ordering in a single crystal of HoMo6S8. An in situ measurement of th e sample resistance allows to correlate the magnetic state with the re sistive behaviour. A bulk superconductivity is associated with any mag netic ordering if the magnetic Ho moment is small enough to keep the i nduction below the critical field B-c2. A partial superconductivity oc curs in ferromagnetic states; it is interpreted by superconducting wal ls in lamellar domain structures. A bulk superconducting phase observe d in a single domain ferromagnetic state is explained by the effect of the demagnetising field.