Universal relationship between low-energy antiferromagnetic fluctuations and superconductivity in BaFe${}_2$(As${}_{1-x}$P${}_x$)${}_2$

Shunsaku Kitagawa, Takeshi Kawamura, Kenji Ishida +5

To identify the key parameter for optimal superconductivity in iron pnictides, we measured the ${}^{31}$P-NMR relaxation rate on BaFe${}_2$(As${}_{1-x}$P${}_x$)${}_2$ ($x=0.22$ and 0…