Crossover of pinning mechanism in La1.85Sr0.15CuO4 crystals -: art. no. 10B109

The pinning mechanism in La1.85Sr0.15CuO4 (LaSCO) was investigated by analyzing the critical current dependence on field and temperature. Unlike other high temperature superconductors such as YBa2Cu3O7, DyBa2Cu3O7-delta, and Nd1.85Ce0.15CuO4-delta, which exhibit a single pinning mechanism over wide temperature and magnetic field ranges, our data in LaSCO show a clear crossover from delta l to delta T-c pinning with temperature or field. While delta l pinning is effective at low fields or low temperatures, delta T-c pinning dominates at high fields or high temperatures. Implications of the pinning mechanism crossover on the unique behavior of the second magnetization peak in LaSCO are discussed. (c) 2005 American Institute of Physics.