Vortex Bose glass in ErBa₂Cu₃O_y films with size-controlled nanorods

Anomalous changes in irreversibility lines (ILs) and critical current properties depending on growth conditions were demonstrated in ErBa ₂Cu₃O_y films with Ba-(Nb,Er)-O nanorods. Despite the formation of nanorods in the matrix at all growth temperatures (Ts), Bose-glass-like vortex pinning was strengthened with decreasing Ts. In particular, the behavior of ILs can be understood in terms of the morphology of introduced nanorods, and Ts strongly affects the vortex states. Our present study suggests the importance of optimization of growth conditions in the production process of rare-earth-based coated conductors containing nanorods as vortex-pinning centers.