Evolution of surface structure, microstructure, and superconducting properties during YBa2Cu3O7a-axis thin film growth

Abstract

The evolution of surface structure, grain microstructure, and superconducting transition temperature of a-axis YBa2Cu3O7 thin films has been studied as a function of film thickness. The grain size increases and develops a bimodal distribution of grain size during film growth, concurrent with an improvement in Tc. The surface structure does not represent the grain size, but rather the development of the bimodal grain structure follows the formation of the surface structure. The results are discussed in terms of thin film growth modes.