Local transport properties of coated conductors by laser-scan imaging methods

Abstract

To observe the superconducting current and structural properties of high critical temperature (Tc) superconductors (HTS), we suggest the following imaging methods: Room temperature imaging (RTI) through thermal heating, low-temperature bolometric microscopy (LTBM) and Raman scattering imaging. RTI and LTBM images visualize thermal-electric voltages as different thermal gradients at room temperature (RT) and superconducting current dissipation at near-Tc, respectively. Using RTI, we can obtain structural information about the surface uniformity and positions of impurities. LTBM images show t he flux flow in two dimensions as a function of the local critical currents. Raman imaging is transformed from Raman survey spectra in particular areas, and the Raman vibration modes can be combined. Raman imaging can quantify the vibration modes of the areas. Therefore, we demonstrate the spatial transport properties of superconducting materials by combining the results. In addition, this enables visualization of the effect of current flow on the distribution of impurities in a uniform superconducting crystalline material. These imaging methods facilitate direct examination of the local properties of superconducting materials and wires. © 2016, Korea Institute of Applied Superconductivity and Cryogenics. All rights reserved.