Iron isotope effect on the superconducting transition temperature and the crystal structure of FeSe1-X

Abstract

The Fe isotope effect (Fe-IE) on the transition temperature Tc and the crystal structure was studied in the Fe chalcogenide superconductor FeSe1-x by means of magnetization and neutron powder diffraction (NPD). The substitution of natural Fe (containing ≃ 92% of 56Fe) by its lighter 54Fe isotope leads to a shift in Tc of 0.22(5) K corresponding to an Fe-IE exponent of αFee = 0.81(15). Simultaneously, a small structural change with isotope substitution is observed by NPD, which may contribute to the total Fe isotope shift of T c. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.