D. Di Gioacchino et al., Frequency, amplitude of magnetic field and temperature characterization ofYBCO using higher harmonics ac susceptibility measurements near T-c, PHYSICA C, 341, 2000, pp. 1101-1102
Analysis on the higher harmonic ac susceptibility of the YBCO samples at fi
xed temperature near T-c versus frequency (107-1200 Hz) and magnitude (2-8
G) of the applied magnetic field have been done. The pinning potential U-p
and critical current density J(c) have been achieved by comparison of exper
imental measurement with the numerical analysis of the non-linear magnetic
diffusion equation inside the samples.