Inverse iron isotope effect on the transition temperature of the (Ba,K)Fe2As2 superconductor.
We report that the (Ba,K)Fe(2)As(2) superconductor (transition temperature, T(c) approximately 38 K) has an inverse iron isotope coefficient alpha(Fe) = -0.18(3) (where T(c) approximately M(-alphaFe) and M is the iron isotope mass); i.e., the sample containing the large iron isotope mass depicts a higher T(c). Systematic inverse shifts in T(c) were clearly observed between the samples using three types of Fe isotopes ((54)Fe, natural Fe, and (57)Fe). This indicates the first evidence of the inverse isotope effect in high-T(c) superconductors. This anomalous mass dependence on T(c) implies an exotic coupling mechanism in Fe-based superconductors.
Shirage
Parasharam M
PM
National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568, Japan. paras-shirage@aist.go.jp
Kihou
Kunihiro
K
Miyazawa
Kiichi
K
Lee
Chul-Ho
CH
Kito
Hijiri
H
Eisaki
Hiroshi
H
Yanagisawa
Takashi
T
Tanaka
Yasumoto
Y
Iyo
Akira
A