Large superconducting Fe Se crystals of（001） orientation have been prepared via a hydrothermal ion release/introduction route for the first time. The hydrothermally derived Fe Se crystals are up to 10 mm×5 mm&#...Large superconducting Fe Se crystals of（001） orientation have been prepared via a hydrothermal ion release/introduction route for the first time. The hydrothermally derived Fe Se crystals are up to 10 mm×5 mm×0.3 mm in dimension. The pure tetragonal FeSe phase has been confirmed by x-ray diffraction（XRD） and the composition determined by both inductively coupled plasma atomic emission spectroscopy（ICP-AES） and energy dispersive x-ray spectroscopy（EDX）. The superconducting transition of the Fe Se samples has been characterized by magnetic and transport measurements. The zero-temperature upper critical field H（c2） is calculated to be 13.2–16.7 T from a two-band model. The normal-state cooperative paramagnetism is found to be predominated by strong spin frustrations below the characteristic temperature T（sn）, where the Ising spin nematicity has been discerned in the FeSe superconductor crystals as reported elsewhere.展开更多
We synthesized a series of Nb2Pd1-xRuxS5 polycrystalline samples by a solid-state reaction method and systematically investigated the Ru-doping effect on superconductivity by transport and magnetic measurements. It is...We synthesized a series of Nb2Pd1-xRuxS5 polycrystalline samples by a solid-state reaction method and systematically investigated the Ru-doping effect on superconductivity by transport and magnetic measurements. It is found that superconductivity is enhanced with Ru doping and is quite robust upon disorder. Hall coefficient measurements indicate that the charge transport is dominated by hole-type charge carriers similar to the case of Ir doping, suggesting multi-band superconductivity. Upon Ru or Ir doping, Hc2/Tc exhibits a significant enhancement, exceeding the Pauli paramagnetic limit value by a factor of approximately 4. A comparison of Tc and the upper critical field （Hc2） amongst the different doping elements on Pd site, reveals a significant role of spin-orbit coupling.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11574370,11274358,and 11190020)the National Basic Research Program of China(Grant No.2013CB921700)the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(Grant No.XDB07020100)
文摘Large superconducting Fe Se crystals of（001） orientation have been prepared via a hydrothermal ion release/introduction route for the first time. The hydrothermally derived Fe Se crystals are up to 10 mm×5 mm×0.3 mm in dimension. The pure tetragonal FeSe phase has been confirmed by x-ray diffraction（XRD） and the composition determined by both inductively coupled plasma atomic emission spectroscopy（ICP-AES） and energy dispersive x-ray spectroscopy（EDX）. The superconducting transition of the Fe Se samples has been characterized by magnetic and transport measurements. The zero-temperature upper critical field H（c2） is calculated to be 13.2–16.7 T from a two-band model. The normal-state cooperative paramagnetism is found to be predominated by strong spin frustrations below the characteristic temperature T（sn）, where the Ising spin nematicity has been discerned in the FeSe superconductor crystals as reported elsewhere.
基金Acknowledgements The authors would like to thank Guanghan Cao for helpful discussions. This work was supported by the Ministry of Science and Technology of China （Grant Nos. 2014CB921203 and 2016YFA0300402）, the National Natural Science Foundation of China （Contract Nos. U1332209 and 11190023）, the Ministry of Education of China （Contract No. 2015KF07）, and the Fundamental Research Funds for the Central Universities of China.
文摘We synthesized a series of Nb2Pd1-xRuxS5 polycrystalline samples by a solid-state reaction method and systematically investigated the Ru-doping effect on superconductivity by transport and magnetic measurements. It is found that superconductivity is enhanced with Ru doping and is quite robust upon disorder. Hall coefficient measurements indicate that the charge transport is dominated by hole-type charge carriers similar to the case of Ir doping, suggesting multi-band superconductivity. Upon Ru or Ir doping, Hc2/Tc exhibits a significant enhancement, exceeding the Pauli paramagnetic limit value by a factor of approximately 4. A comparison of Tc and the upper critical field （Hc2） amongst the different doping elements on Pd site, reveals a significant role of spin-orbit coupling.
