Structural and resistivity properties of Fe₁-ₗCoₓSe single crystals grown by the molten salt method

A series of tetragonal Fe₁-ₗCoₓSe single crystals with a complete Co doping range (0x0. 52) up to its solid solubility limit in FeSe have been grown by an eutectic AlCl₃/KCl molten salt method. The typical lateral size of as-grown Fe₁-ₗCoₓSe single crystals is 1-5 mm. The chemical composition and homogeneity of the crystals was examined by both inductively coupled plasma atomic emission spectroscopy and energy dispersive spectrometer. X-ray diffraction analysis demonstrates that the crystal lattice parameters a and c are both linearly decreased with increasing Co doping level x. In the whole doping range, all the samples show metallic behaviour in contrast to a metal insulator transition of Cu-doped FeSe according to the resistivity measurements