Defining optimal thickness for maximal self-fieldJcin YBCO/CeO2multilayers grown on buffered metal.

ABSTRACT

The effect of multilayering YBa2Cu3O6+x(YBCO) thin films with sequentially deposited CeO2layers between YBCO layers grown on buffered metallic template is investigated to optimize the self-field critical current densityJc(0). We have obtained that the improvement inJc(0)clearly depends on the YBCO layer thickness and temperature, where at high temperatureJc(0)can be increased even 50% when compared with the single layer YBCO films. Based on our experimental results and theoretical approach to the growth mechanism during multilayer deposition, we have defined a critical thickness for the YBCO layer, where the maximal self-fieldJc(0)is strongly related to the competing issues between the uniform and nonuniform strain relaxation and the formation of dislocations and other defects during the film growth. Our results can be directly utilized in the future coated conductor technology, when maximizing the overall in-fieldJc(B)by combining both the optimal crystalline quality and flux pinning properties typically in bilayer film structures.