Moessbauer investigation of iron doped YBa2Cu307-x

We have recorded 57Fe Moessbauer spectra of YBa2 (Cu1.y Fey)3O7.x powder sample and uniaxially oriented powder for 0.01 ≤y≤0.1 and x≅O or x≅1. In the superconducting x≅O compounds we see three subspectra for y>0.01 and four subspectra for y=0.01. These subspectra correspond to different oxygen configurations around the iron atoms. From the oriented YBa2 (Cu.94 Fe.06)3O7 and YBa2 (Cu.9 Fe.1)3O6 compounds we deduce that more than 90% iron substitutes Cu(1) site. The iron magnetic moments order antiferromagnetically at ≅18 K and ≅1.5 K for the x=0, y=0.06 and x=0, y=0.01 compounds respectively