Synthesis and properties of La-doped CaFe ₂ As ₂ single crystals with T _c =42.7 K

Abstract

Large single crystals of La-doped CaFe2As2 were successfully synthesized by\nthe FeAs self-flux method. The x-ray diffraction patterns suggest high\ncrystalline quality and c-axis orientation. By substitution of trivalent La3+\nions for divalent Ca2+, the resistivity anomaly in the parent compound CaFe2As2\nis completely suppressed and a superconducting transition reaches the value of\n42.7 K, which is higher than that of about 30 K reported in Saha S. R. et al.,\narXiv:1105.4798v1. The upper critical field has been determined with the\nmagnetic field along ab-plane and c-axis, yielding an anisotropy of about 3.3.\n