Visualization of grain structure in HTS HoBCO coated conductor using laser induced thermoelectric voltage

Grain structure imaging in high temperature superconductor coated conductor studies is crucial because its ability to carry current strongly depends on the microstructure. We have come with a novel method of imaging the CC grain structure using laser induced thermoelectric voltage in mm length with a resolution of 2 to 3μm on a textured metal based HoBCO CC microbridge. Due to anisotropic difference between the ab-plane and the c-axis of the CC, we are able to visualize its grain structure at high resolution. This responsive Seebeck voltage amplitude is proportionate to the tilting angle of the CuO ₂ plane of the grains relative to the tape surface. From 2D map of voltage phase signal, we can clearly visualize domain structure depending on the tilting direction of the grains. Further statistical analysis showed a good relationship with XRD crystal analysis in literature.