STUDY OF SUPERCONDUCTING FLUCTUATION USING YBA2CU3O7 SINGLE-CRYSTALS

In normal-state magnetoresistance studies, the layered structure and short coherence length of high-T(C) superconductors make it possible to observe the Zeeman effect on superconducting fluctuation. Two problems, however, remain: (1) the Zeeman effect on the Maki-Thompson fluctuation (MTZ) in the Aronov-Hikami-Larkin (AHL) theory, and (2) whether the the clean or dirty limit approximation is valid. We have therefore studied the magnetoresistance of YBa2Cu3O7 bulk single crystals. We experimentally demonstrate that the MTZ fluctuation as presented in the AHL theory are absent. Moreover, we find that clean limit analysis without the MTZ component (ALO+MTO+ALZ) closely fits the experimental data. We obtained results quantitatively consistent with the results of recent optical and transport studies using YBa2Cu3O7 single crystals.