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

We have determined the stability line in the 1/T-log[P(O2)] phase space for the synthesis of Nd1+xBa2-xCu3Oy (NdBCO) films. A systematic study of Tc, Jc, and ρ(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 degree 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 YBa2Cu3O7-δ film growth. copyright 1999 American Institute of Physics