Single-crystal growth and superconducting properties of LiFeAs

We report the successful growth of high-quality single crystals of LiFeAs with lateral sizes up to 5 x 5 mm(2) by the Sn-flux method. Electrical resistivity studies reveal that the superconducting onset temperature is 18.2 K with a transition width less than 1.1 K and the ratio of room temperature to residual resistivity is about 24. Bulk superconductivity is supported by perfect shielding in the magnetic susceptibility and a clear jump in the specific heat C-p, resulting in Delta C-p/T approximate to 20.0 mJ/mol K-2. Upper-critical-field slopes of dH(c2)(c)/dT approximate to -1.39 and dH(c2)(ab)/dT approximate to -2.99 T/K near T-c predict zero-temperature upper critical fields of H-c2(c)(0) approximate to 17.2 and H-c2(ab)(0) approximate to 36.9 T and coherence lengths of xi(ab) - 4.4 and xi(c) - 2.0 nm in a single-band model. This result points to a modest superconducting anisotropy about 2.3 in LiFeAs. Copyright (C) EPLA, 2010