PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS, cilt.391, sa.1, ss.67-74, 2003 (SCI-Expanded)
Measurements of fundamental and high-order harmonic susceptibilities, chi(n), = chi(n)' + ichi(n)" (n = 1, 2, 3, 5 and 7), were made on a cylindrical BSCCO(2223) bulk sample in the range 15-120 K at fields ranging from 8 to 1600 A/m and 1000 Hz frequency. They exhibit dependence on the amplitude of the ac field. The observed dependences were analyzed by using the Bean model. We have obtained an empirical function for the penetration field H-p = H-alpha(1 - t)(beta), with t = T/T-cb. Best fitting to data was obtained with parameters H-alpha approximate to 3.3 x 10(4) A/m and beta = 2.05. In addition, ac losses were calculated at some fixed temperatures to compare theoretical expectations. The experimental values agree well with the theoretical findings. AC losses were calculated under external fields ranging from 0 to 1600 A/m and, at 84.35 K, the experimental results are shown to agree well with the theoretical values. (C) 2003 Elsevier Science B.V. All rights reserved.