Magnetic relaxation and irreversibility in a superconducting Tl\u3csub\u3e2\u3c/sub\u3eBa\u3csub\u3e2\u3c/sub\u3eCa\u3csub\u3e2\u3c/sub\u3eCu\u3csub\u3e3\u3c/sub\u3eO\u3csub\u3e10±x\u3c/sub\u3e thin film

The magnetic relaxation in a Tl2Ba2Ca2Cu3O10±x superconducting thin film has been measured at a range of temperatures (5–70 K) and field strengths (500–5000 Oe). Measurements reveal that the relaxation obeys a logarithmic time dependence in the time interval 2000 s\u3ct\u3c12 000 s. The relaxation rate is both temperature and field dependent. The average pinning potential U* calculated from the relationship U*=kT/[(-1/Mi)dM/d lnt] is in the range 20–70 meV, which is similar to those of Y-Ba-Cu-O and (Bi,Pb)-Sr-Ca-Cu-O. The anomalous increase of U* at higher temperature is found to be closely related to the irreversibility line