A study of the growth mode of Re1+xBa2-xCu3O7-delta (Re = Nd, Y, Sm) epitaxial films deposited by physical vapour deposition.

A study of the 2D vs 3D growth in c-axis Nd1+xBa2xCu3O7-delta films and a s tudy of the crossover between a-axis to c-axis growth in the Re1+xBa2-xCu3O 7-delta (RBCO) family is reported. We found that c-axis stoichiometric Nd1B a2Cu3O7 films exhibit a 3D layered island-growth, possibly originated by sc rew and half loop dislocations. On the contrary, a continuous 2D growth is found in off-stoichiometry films, characterised by Nd excess. The amount of a-axis in Nd1+xBa2-xCu3O7 films deposited at different temperatures has be en carefully determined by XRD. The experimental results are interpreted in the framework of a theoretical model of the nucleation of RBCO films. The model provides a quantitative description and a satisfactory fit of experim ental data from our experiment and from the Current litterature.