Synthesis, anisotropy, and superconducting properties of LiFeAs single crystal

A LiFeAs single crystal with T-c(onset)similar to 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, gamma(rho)=rho(c)/rho(ab), was approximately 3.3 at T-c(onset). The upper critical fields had large H-c2(parallel to ab) and H-c2(parallel to c) values of 83.4 T and 72.5 T, respectively, and an anisotropy ratio is gamma(H)=H-c2(parallel to ab)/H-c2(parallel to c)similar to 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). (C) 2010 American Institute of Physics. [doi:10.1063/1.3435472]