Observations of a hysteresis loss valley in yttrium barium copper oxide superconductors

摘要: We present measurements of the ac susceptibility sintered yttrium barium copper oxide pellets prepared by a melt processed solid state reaction method, with different amounts ZnO added. The were performed versus temperature T for several magnetic field amplitudes Hac in presence static bias fields Hb directed along Hac. For all our samples, each choice Hac, imaginary part traces peak, denoted χ″max, centered at Tmax.We also find that plots values χ″max vs and Tmax generate curves display valley. Calculations hysteresis losses, exploiting critical-state model where critical current density jc=α(T)∕Bn, reproduce experimental data quite well.