Synthesis, anisotropy, and superconducting properties of LiFeAs single crystal

摘要

A LiFeAs single crystal with T_c~(onset) ～19.7 K was grown in a sealed tungsten crucible using the Bridgeman method. The electrical resistivity experiments revealed a ratio of room temperature to residual resistivity of approximately 46 and 18 for the in-plane and out-of plane directions, respectively. The estimated anisotropic resistivity, γ_p=ρ_c/ρ_(ab), was approximately 3.3 at T_c~(onset). The upper critical fields had large H_(c2)~(‖ab) and H_(c2)~(‖c) values of 83.4 T and 72.5 T, respectively, and an anisotropy ratio is γH_(c2)~(‖ab)/H_(c2)~(‖c)～1.15. The high upper critical field value and small anisotropy highlight the potential use of LiFeAs in a variety of applications. The calculated critical current density (J_c) from the M-H loop is approximately 10~3 A/cm~2.