FLUX-PINNING BEHAVIOR AND THE INTERLAYER COUPLING OF THE HG0.7CR0.3SR2CUO4+DELTA SUPERCONDUCTOR

previously the compound of Hg0.7Cr0.3Sr2CuO4+delta was believed to exh ibit an enhanced flux-pinning behavior compared to the pristine HgBa2C uO4+delta. As candidates for its origin, possible extended defects of a superlattice in the c direction or a strong coupling deduced from a reduced distance between CuO2 planes have been proposed. To clarify th ese, we extensively measured the magnetization of the c-axis aligned g rains of this compound. Contrary to previous belief, the irreversibili ty line and magnetic hysteresis show reduced pinning properties. From the analysis of the reversible magnetizations based on the vortex fluc tuation model, the high-field scaling analysis, and the Hao-Clem model , the interlayer coupling was also confirmed to be weak. The proposed extended defects seem not to be effective in pinning vortices in Hg0.7 Cr0.3Sr2CuO4+delta. [S0163-1829(98)04922-4].