Voltage response of AC susceptibility and pinning effects in Hg0.69Pb0.31Ba2Ca2Cu3O8+delta

We have studied the voltage response of AC susceptibility, and from the ima ginary part of the susceptibility experimental results a new method is pres ented in terms of the material equation to investigate the pinning properti es and the dynamical response in our Hg0.69Pb0.31Ba2Ca2Cu3O8+delta sample. We also discuss the differences between the voltage criterion and our AC re sponse measurement method in order to determine the value of the true criti cal current density. The result shows that the later method reflects the tr ue critical state of high-temperature superconductivity better than the gen eral voltage criterion.