Bulk Superconductivity at 2.6 K in Undoped RbFe2As2
Abstract
The iron arsenide RbFe2As2 with the ThCr2Si2-type structure is found to be a bulk superconductor with Tc=2.6 K. The onset of diamagnetism was used to estimate the upper critical field Hc2(T), resulting in dHc2/dT=-1.4 T/K and an extrapolated Hc2(0)=2.5 T. As a new representative of iron pnictide superconductors, superconducting RbFe2As2 contrasts with BaFe2As2, where the Fermi level is higher and a magnetic instability is observed. Thus, the solid solution series (Rb,Ba)Fe2As2 is a promising system to study the crossover from superconductivity to magnetism.
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