Annealing of irradiation induced defects in a LaSrCuO crystal

Annealing experiments were performed on a LSCO single crystal irradiated with fast neutrons to a fluence of 2.52/spl times/10/sup 18/ n/cm/sup 2/. This fluence increased the critical current density by a factor of 2-3. The sample was annealed for a total of 4.5 hours at 200/spl deg/C and 8 hours at 300/spl deg/C. It was found that annealing of LSCO has a much lesser effect on its critical current density, particularly along the c axis, compared to YBCO. It is hypothesized that the reduced annealing effect is due to the formation of either a more stable interstitial cluster (compared to the Cu-O cluster in YBCO), or clusters which do not act as pinning sites.