AC LOSSES IN POWDER-IN-TUBE BI2CA2SR2CU3O10 TAPES AT POWER FREQUENCIES

ac losses in Bi2Ca2Sr2Cu3O10 tapes, which were fabricated by the powder-in-Ag tube method, were measured with the applied field parallel to the tape face for frequencies 15-180 Hz and at 4.2 and 65-77 K. The losses were found to be significantly lower than those for sintered bars of YBa2Cu3O7 and the frequency dependence of the losses at 77 K was linear indicating that the losses were hysteretic in origin. However, at 4.2 K a significant contribution to the losses from the eddy current losses in the Ag sheath was apparent for frequencies greater than 30 Hz. Furthermore, the magnetic field dependence of the losses at 77 K followed the Bean model surprisingly well.