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

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

Local Current Flow and Dissipation in Multi-filamentary YBCO Coated Conductor under the Influence of Microstructural Inhomogeneity

Local current flow and dissipation in a three parallel 100μm-wide filamentary YBCO tape had been studied in order to investigate the current carrying capability in each filament under the influence of local obstacles. Structural inhomogeneity and local flux flow dissipation have been visualized by using thermal laser stimulation technique and its local current density was measured by scanning SQUID microscope. By combining local current distribution with dissipation, we made estimations on local the J_c and I_c values in each filament. Results have shown a current imbalance on the current sharing in the filamentary structure. It has been shown that the I_c is possibly influenced significantly if the filament size reaches 100μm scale because of current blocking obstacles

Local Current Flow and Dissipation in Multi-filamentary YBCO Coated Conductor under the Influence of Microstructural Inhomogeneity

Local current flow and dissipation in a three parallel 100μm-wide filamentary YBCO tape had been studied in order to investigate the current carrying capability in each filament under the influence of local obstacles. Structural inhomogeneity and local flux flow dissipation have been visualized by using thermal laser stimulation technique and its local current density was measured by scanning SQUID microscope. By combining local current distribution with dissipation, we made estimations on local the J_c and I_c values in each filament. Results have shown a current imbalance on the current sharing in the filamentary structure. It has been shown that the I_c is possibly influenced significantly if the filament size reaches 100μm scale because of current blocking obstacles