Application of power law in melt-textured YBa2Cu3Oy

E similar to J curves of melt-textured YBa2Cu3Oy were determined at various temperatures and magnetic fields with the magnetic sweeping method by VSM. Using an widely observed experiential power law E = E-c(J/J(c))(n), we obt ained the characteristic pinning potential U-0(T, H) and critical current d ensity J(c)(T, H) by an appropriate definition of E-c. By analyzing the phy sical meaning of U-0(T, H) and J(c)(T, H), we interpreted the peak effect o f U-0(T) in high temperature superconductors (HTSC's).