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  Steckel, F.; Roslova, M.; Beck, R.; Morozov, I.; Aswartham, S.; Evtushinsky, D.; Blum, C.G.F.; Abdel-Hafiez, M.; Bombor, D.; Maletz, J.; Borisenko, S.; Shevelkov, A.V.; Wolter, A.U. B.; Hess, C.; Wurmehl, S.; Buechner, B.: Crystal growth and electronic phase diagram of 4d-doped Na_1-δ Fe_1-xRh_xAs in comparison to 3d-doped Na_1-δ Fe_1-xCo_xAs. Physical Review B 91 (2015), p. 184516/1-9

10.1103/PhysRevB.91.184516
Open Access Version (externer Anbieter)

Abstract:
Single crystals of Na1−δFe1−xTxAs with T = Co, Rh have been grown using a self-flux technique. The crystals were thoroughly characterized by powder x-ray diffraction, magnetic susceptibility, and electronic transport with particular focus on the Rh-doped samples. Measurements of the specific heat and ARPES were conducted exemplarily for the optimally doped compositions. The spin-density wave transition (SDW) observed for samples with low Rh concentration (0≤x≤0.013) is fully suppressed in the optimally doped sample. The superconducting transition temperature (Tc) is enhanced from 10 K in Na1−δFeAs to 21 K in the optimally doped sample (x=0.019) of the Na1−δFe1−xRhxAs series and decreases for the overdoped compounds, revealing a typical shape for the superconducting part of the electronic phase diagram. Remarkably, the phase diagram is almost identical to that of Co-doped Na1−δFeAs, suggesting a generic phase diagram for both dopants.