Current Percolation Characteristics of IBAD Coated Conductors

We have investigated IBAD coated conductors by variable temperature scanning laser microscopy (VTSLM) to map how current flows in superconducting transition and superconducting region. We examined various factors that make non-uniform current distribution and found that the current flow was affected by the grain boundary network, the physical bending of samples, and the surface contaminations. On the basis of data analysis, we deduced 65$\mu $m $\sim $ 150$\mu $m as percolation cluster feature sizes. Below the critical temperature, we have investigated J$_{c}$ to establish the relationship of the T$_{c}$ and $\delta $V and J$_{c}$, and we conclude that lower T$_{c}$ and higher $\delta $V area has lower J$_{c}$. We also found several circular shapes of about 100$\mu $m $\times $ 130$\mu $m diameter from a sample. Those dots had definitely higher T$_{c}$ than the surrounding area and created non-uniform current flow. In this presentation, we will report more about VTSLM images around the dots and the characteristics of current bottleneck features which are related with the lower J$_{c}$.