Swift heavy-ion irradiation effects on the single crystal La1.85Sr0.15CuO4

The behavior of a vortex system in the presence of columnar defects in a La1.85Sr0.15CuO4 single crystal irradiated with swift heavy ions (3.5 GeV 136Xe31+) is studied by measuring magnetization and AC susceptibility. The absolute value of the magnetization of the irradiated sample is significantly enhanced compared to the unirradiated one. The irreversibility line is shifted to higher temperatures as the defect density increases. It is found that for B > Bcr similar 0.5 T, ϰ" of irradiated samples exhibits double peaks, suggesting that the liquid-glass transition proceeds via two steps.