Superconducting property variation with partially Mn substitution in FeSe superconductors
Yung-Yuan Hsu1*, Muhammad Raheel1
1Department of Physics, National Taiwan Normal University, Taipei, Taiwan
* Presenter:Yung-Yuan Hsu,
One major difficulty in researches on FeSe-related superconductivities is the limited chemical substitution options for iron in this system, which greatly limits the tuning ranges of physical parameters for investigations. In this report, high purity partially Mn substituted FeSe superconductors (up to 5% substitution) are successfully prepared by vapor-solid reaction followed by high-temperature melting and long-time annealing. The superconducting transition Tc increases with Mn substitution and reaches its maximum of Tc ~ 11.5 K for 4% Mn substitution. The lower critical field Hc1 (0) decreases with the substitution indicating an increase of superconducting penetration depth and possibly lowering of superconducting carrier density. The systematic evolution of anisotropic superconducting penetration depth and superconducting carrier density as a function of substitution content will be presented and discussed in detail.

Keywords: FeSe superconductor, penetration depth, lower critical field