Discovery of a novel 112-type iron-pnictide and La-doping induced superconductivity in Eu_(1-x)La_xFeAs_2(x=0–0.15)

We report the discovery and characterization of a novel 112-type iron pnictide EuFeAs2, with La-doping induced superconductivity in a series of Eu1- xLaxFeAs2. The polycrystalline samples were synthesized through solid state reaction method only within a very narrow temperature window around 1073 K. Small single crystals were also grown from a flux method with the size about 100μm. The crystal structure was identified by single crystal X-ray diffraction analysis as a monoclinic structure with space group of P2 1/m. From resistivity and magnetic susceptibility measurements, we found that the parent compound EuFeAs2 shows distinct anomalies probably due to the Fe2＋ related antiferromagnetic/structural phase transition near 110K and the Eu2＋ related antiferromagnetic phase transition near 40K. La-doping suppressed both phase transitions to lower temperatures and induced superconducting transitions with a Tc - 11 K for Eu0.85La0.15FeAs2.

We report the discovery and characterization of a novel 112-type iron pnictide Eu Fe As_2, with La-doping induced superconductivity in a series of Eu_(1-x)La_xFeAs_2. The polycrystalline samples were synthesized through solid state reaction method only within a very narrow temperature window around 1073 K.Small single crystals were also grown from a flux method with the size about 100 lm. The crystal structure was identified by single crystal X-ray diffraction analysis as a monoclinic structure with space group of P21/m. From resistivity and magnetic susceptibility measurements, we found that the parent compound Eu Fe As_2 shows distinct anomalies probably due to the Fe^(2+) related antiferromagnetic/structural phase transition near 110 K and the Eu^(2+) related antiferromagnetic phase transition near 40 K.La-doping suppressed both phase transitions to lower temperatures and induced superconducting transitions with a Tc^11 K for Eu_(0.85)La_(0.15) Fe As_2.