NMR studies on the superconducting symmetry of iron pnictide systems

作者：Kobayashi Yoshiaki; Lee Sang Chul; Takahashi Hidefumi; Moyoshi Taketo; Sato Masatoshi^*

来源：Physica C-Superconductivity and Its Applications, 2010, 470: S472-S474.

DOI：10.1016/j.physc.2009.11.135

• LaFe(1-y)Co(y)AsO(1-x)F(x) (x=0.11)
• NMR
• Impurity effects on T(c)
• Superconducting symmetry

NMR longitudinal relaxation rates 1/T(1) have been measured for superconducting samples of LaFe(1-y)Co(y)AsO(1-x)F(x) with x = 0.11. The results show that the temperature (T) dependences of 1/T(1) of these samples can approximately be described by the relation 1/T(1) proportional to T(6) in the T region similar to 0.4T(c) < T< T(c), T(c) being the superconducting transition temperature. It is markedly different from the behavior 1/T(1) proportional to T(2.5-3.0) observed by many other groups in the entire T range (similar to 0.1T(c) < T< T(c)). We propose that the spatial inhomogeneity of the superconducting order parameter Delta within the samples is a possible origin of the T(2.5-3.0)-like behavior, while the T(6)-like behavior is observed for samples without the inhomogeneity of Delta.

• 出版日期2010-12