Growth and superconducting properties of F-substituted ROBiS₂ (R=La, Ce, Nd) single crystals

F-substituted ROBiS₂ (R=La, Ce, Nd) superconducting single crystals with different F concentrations were grown successfully using a CsCl/KCl flux. All crystals produced had a plate-like shape, with a well-developed ab-plane 1-2 mm in size. Electron probe microanalysis did not detect any Cs, K, or Cl flux components in the crystals. As-grown single crystals of F-substituted LaOBiS₂ and CeOBiS₂ exhibited superconductivity at about 3 K, whereas F-substituted NdOBiS₂ was superconductive at approximately 5 K. The superconducting anisotropy of single crystal F-substituted LaOBiS₂ and NdOBiS₂ was estimated to be 30-45 according to the effective mass model, whereas the anisotropy for F-substituted CeOBiS₂ single crystals was 13-21. The F-substituted CeOBiS₂ single crystals exhibited a magnetic order around 7 K that apparently coexisted with superconductivity below approximately 3 K.