Effect of Water and Iron on Slowly and Rapidly Cooled Y-1 Ba2Cu3O6+x Superconductors: An EPR/NMR Study

We present here a study of the effect of Fe doping and hydration on the NMR, EPR spectra and Tc of slowly and rapidly cooled Y-1 Ba2Cu3O6+x Superconductor. The g-values of the EPR signals are related to Cu2+ ions in six-fold coordination. Tc is suppressed 10–20°C due to changes in processing conditions and the addition of Fe. The 89Y MAS-NMR spectra show that Y is more shielded (more ionically bonded) in the slowly cooled sample than in the rapidly cooled sample and the hydrated slowly cooled sample is less shielded. The effect of hydration on 89Y chemical shift is consistent with the presence of protons near the Y.