Abstract
We have investigated harmonic ac susceptibilities Xn=Xn'-iXn" (n=1, 2, 3) of a ceramic superconductor HoBa2Cu4Oy synthesized by the polymerized complex method. The sample are immersed in an external field H(t)= Hdc+ Haccos(ωt), where Hdc (≥0) is a dc bias field and Hac (>0) is an ac field amplitude. Measurements of Xn were carried out for μOHac = 0.01-0.1 mT and the fundamental frequency was 132 Hz. The observed results were analyzed within the construct of the Kim-Anderson model for critical current density and were compared to those previously obtained for other sintered ceramic superconductors. Details of the measurement and the analysis are presented.
