Role of magnetic dopants in the phase diagram of Sm 1111 pnictides: The case of Mn

none15siThe deliberate insertion of magnetic Mn dopants in the Fe sites of the optimally doped SmFeAsO0.88F0.12 iron-based superconductor can modify in a controlled way its electronic properties. The resulting phase diagram was investigated across a wide range of manganese contents (x) by means of muon-spin spectroscopy (μSR), both in zero and in transverse fields, to probe the magnetic and the superconducting order, respectively. The pure superconducting phase (at x<0.03) is replaced by a crossover region at intermediate Mn values (0.03≤x