Controllable change of oxygen stoichiometry in YBa2(Cu1-xFex)3O7-y and its effect on superconductivity and local structure

System of YBa2(Cu0.99Fe0.01)3O7-y samples with exactly measured oxygen content in 0.03≤y≤0.80 range was obtained for the first time. It was established that the presence of 1% of paramagnetic iron impurity didn't affect the general character of the dependence of superconducting transition temperature Tc. Moessbauer spectra were used to establish, that not less, than 90% iron atoms were located in Cu1 point, about 70% of iron atoms were located in twin domains and about 20% - in domain boundaries