Phase stability for the in situ growth of Nd1+xBa2−xCu3Oy films using pulsed-laser deposition

We have determined the stability line in the $\text{1/T−}\log \mathrm{[P(}{\mathrm{O}}_{\mathrm{2}}\mathrm{)]}$ phase space for the synthesis of ${\mathrm{Nd}}_{\text{1+x}}{\mathrm{Ba}}_{\text{2−x}}{\mathrm{Cu}}_{\mathrm{3}}{\mathrm{O}}_y$ (NdBCO) films. A systematic study of $T_c,$ $J_c,$ and $\mathrm{\rho (T)}$ dependence on oxygen partial pressure and temperature for the deposition of thin NdBCO films grown by pulsed-laser deposition was performed. The conditions for optimal NdBCO film growth were determined by varying oxygen partial pressure from 0.02 to 400 mTorr, and substrate temperature between 730 and 800 °C. The results show that the best NdBCO films are obtained at oxygen pressures in the range of 0.2–1.2 mTorr, depending on the substrate temperature. This is more than two orders-of-magnitude lower than the correspondent oxygen pressure appropriate for ${\mathrm{YBa}}_{\mathrm{2}}{\mathrm{Cu}}_{\mathrm{3}}{\mathrm{O}}_{\mathrm{7-\delta }}$ film growth.