The flux pinning potential of Ag/Bi-2223 tapes for H//c-axis

Flux pinning potential U(T,H) of Ag/Bi-2223 tapes has been determined throu gh measurements of transport current density J(T,H) in applied magnetic fie ld from 0 to 3T and at temperature from 23K to 77K. The field was perpendic ular to the broad surface of the tape. Generally, U(T,H) and J(T,H) are reg arded as U(T,H) = U(T)U(H) and J(T,H) = J(T)J(H), respectively. U(T,H) can be obtained by fitting the function of J(T,H) if a proper theory of flux dy namics would be used. In the case of transport current density, the experim ental J(H) is found to be linear with ln mu H-0, that conforms to Andson's flux dynamics theory. By using the theory, the pinning potential U(T,H) for Ag/Bi-2223 tapes is determined and formulated quantitatively. The resultin g flux pinning potential U(T,H) is shown in a three dimension diagram.