Absence of an appreciable iron isotope effect on the transition temperature of the optimally doped SmFeAsO(1-y) Superconductor.
We report the iron (Fe) isotope effect on the transition temperature (T(c)) in oxygen-deficient SmFeAsO(1-y), a 50-K-class, Fe-based superconductor. For the optimally doped samples with T(c) = 54  K, a change of the average atomic mass of Fe (M(Fe)) causes a negligibly small shift in T(c), with the Fe isotope coefficient (α(Fe)) as small as -0.024 ± 0.015 (where α(Fe)=-d lnT(c)/dlnM(Fe)). This result contrasts with the finite, inverse isotope shift observed in optimally doped (Ba,K)Fe2As2, indicating that the contribution of the electron-phonon interaction markedly differs between these two Fe-based high-T(c) superconductors.
Shirage
Parasharam M
PM
National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568, Japan. paras-shirage@aist.go.jp
Miyazawa
Kiichi
K
Kihou
Kunihiro
K
Kito
Hijiri
H
Yoshida
Yoshiyuki
Y
Tanaka
Yasumoto
Y
Eisaki
Hiroshi
H
Iyo
Akira
A