Pressure-tuned superconductivity and normal-state behavior in Ba(Fe0.943Co0.057)2As2 near the antiferromagnetic boundary

• Main Authors: Liu, W., Wu, Y. F., Li, X. J., Bud'ko, S. L., Canfield, P. C., Li, P. G., Mu, G., Hu, T., Almasan, C. C., Xiao, H., Panagopoulos, Christos
• Other Authors: School of Physical and Mathematical Sciences
• Format: Article
• Language: English
• Published: 2018
• Subjects: Superconductivity; Antiferromagnetic Boundary; DRNTU::Science::Physics
• Online Access: https://hdl.handle.net/10356/90157; http://hdl.handle.net/10220/47203
• Institution: Nanyang Technological University

Superconductivity in iron pnictides is unconventional and pairing may be mediated by magnetic fluctuations in the Fe sublattice. Pressure is a clean method to explore superconductivity in iron based superconductors by tuning the ground state continuously without introducing disorder. Here we present a systematic high pressure transport study in Ba(Fe1-xCox)2As2 single crystals with x=0.057, which is near the antiferromagnetic instability. Resistivity ρ=ρ0+ATn was studied under applied pressure up to 7.90 GPa. The parameter n approaches a minimum value of n ≈ 1 at a critical pressure Pc = 3.65 GPa. Near Pc, the superconducting transition temperature Tc reaches a maximum value of 25.8 K. In addition, the superconducting diamagnetism at 2 K shows a sudden change around the same critical pressure. These results may be associated with a possible quantum critical point hidden inside the superconducting dome, near optimum Tc.