Superior properties of SmBCO coated conductors at high magnetic fields and elevated temperatures

In addition to the well investigated YBa₂Cu₃O_7?δ (Y-123, YBCO) compound, many other rare earth-123 compounds are candidate materials for the production of coated conductors. Sm-123 seems to be an excellent alternative because of its higher transition temperature (T_c) and higher critical current densities (J_c) in external magnetic fields. Because of the fast decrease of J_c in YBCO at elevated temperatures, especially around the boiling point of liquid nitrogen, the slightly higher T_c can be an important advantage. Recently, significant progress has been made in the production of long length Sm-123 based coated conductors. We report here on transport measurements on these conductors in the liquid nitrogen temperature range. The critical current densities were determined as a function of the applied field and the crystallographic orientation under maximum Lorentz force configuration. A shift of the c-axis (～7°) from the tape normal was found. The conductor properties were compared to those of commercially available YBCO coated conductors. The critical current densities as well as the irreversibility fields are higher in the SmBCO tapes, thus demonstrating the superior properties of the Sm-123 compound.