An anomalous tail effect in the resistivity transition and weak-link behavior of superconducting NdFeAsO(0.88)F(0.12)

作者：Sun Y^*; Ding Y; Zhuang J C; Cui L J; Yuan X P; Shi Z X; Ren Z A

来源：Superconductor Science and Technology, 2011, 24(8): 085011.

DOI：10.1088/0953-2048/24/8/085011

The temperature dependent resistivity of the iron-based superconductor NdFeAsO(0.88)F(0.12) was measured under different applied fields and excitation currents. The Arrhenius plot shows an anomalous tail effect, which contains two obvious stages of decreasing resistivity. The first is caused by the normal superconducting transition, and the second is supposed to be related to the weak link between the grains. A model for the resistivity decrease related to the weak-link behavior is proposed, which is based on the Josephson junctions formed by the impurities in grain boundaries like FeAs, Sm(2)O(3) and cracks together with the adjacent grains. These Josephson junctions can be easily broken by the applied fields and the excitation currents, leading to an anomalous resistivity tail in many polycrystalline iron-based superconductors. The calculated drop in resistivity agrees well with the experimental data, which indicates the correctness of the explanation for the obtained anomalous tail effect.

• 出版日期2011-8
• 单位东南大学; 中国科学院