Hysteretic loss reduction in striated YBCO

Magnetization vs. applied field measurements (M-H loops) were taken on short samples of YBa2Cu3O7-delta (YBCO) thin films which were divided into narrow filaments. The YBCO was deposited using pulsed laser deposition onto single-crystal LaAlO3 substrates, with a range of film thicknesses from 0.25 to 0.33 mum. Using a YAG laser, the thin films were patterned into linear striations by removing strips of the superconductor by laser ablation. The resulting striated filamentary structure serves to reduce the effective width of the YBCO films and hence the hysteresis loss in the superconducting samples. The magnetization measurements were taken over the temperature range of 4.2-77 K in applied fields of 0-17 kOe using a vibrating sample magnetometer. The measured hysteresis losses show a highly linear relationship between superconductor filament width and hysteresis loss as anticipated. However, the laser ablation process did result in the redeposition of YBCO along the edges of individual filaments. Degradation of T-c and J(c) due to the ablation process is discussed. (C) 2002 Elsevier Science B.V. All rights reserved.