Why are sputter deposited Nd1+xBa2-xCu3O7-delta thin films flatter than NdBa2Cu3O7-delta films?

High-resolution electron microscopy and scanning tunneling microscopy have been used to compare the microstructure of NdBa2Cu3O7-delta and Nd1+xBa2-xC u3O7-delta thin films. Both films contain comparable amounts of Nd2CuO4 inc lusions. Antiphase boundaries are induced by unit cell high steps at the su bstrate or by a different interface stacking. In Nd1+xBa2-xCu3O7-delta the antiphase boundaries tend to annihilate by the insertion of extra Nd layers . Stacking faults, which can be characterized as local Nd2Ba2Cu4O9 inclusio ns, also absorb the excess Nd. A correlation is made between the excess Nd and the absence of growth spirals at the surface of the Nd-rich films. (C) 2001 American Institute of Physics.