Comparison of AC transport current loss in different YBCO coated conductor tapes measured at 4.2 K

The YBa2Cu3O7-x (YBCO) superconducting tapes are promising candidates for using in applications at liquid helium temperature. Their parameters have not been adequately explored in these conditions by now. This work deals with AC transport current loss comparison of different YBCO coated conductors in self field in liquid helium (LHe). For experiments we used YBCO tapes of different widths, both with and without ferromagnetic substrate and stabilizing layer. The measurements are based on the lock-in technique using a special measurement device working on the principle of a current transformer. The device enables to measure up to high currents (order of kA). The heating of current leads and LHe evaporation is minimized. The experimental data show very good transport properties of YBCO tapes in LHe (high critical currents and corresponding transport current loss). This contribution is completed by AC transport current losses of used YBCO samples measured in liquid nitrogen (LN2). (C) 2012 Published by Elsevier B.V. Selection and/or peer-review under responsibility of the Guest Editors.