Low field AC susceptibility in low temperature for a Bi2Sr2CaCu2O8 single crystal

Using single crystals of Bi2Sr2CaCu2O8, a detailed study for the thermoremanent magnetization (TRM) was performed at low AC applied field in the low temperature region (5≤T≤20 K). Below approximately 20 K, the AC susceptibility of TRM shows anomalous dispersion response with large amplitude. The origin of the unstable response has been discussed in relation with the pinning force.