F-doped LaOBiSe$_{ 2}$ superconducting single crystals with typical size of 2$\times$4$\times$0.2 mm$^{ 3}$ are successfully grown by flux method and the superconducting properties are studied. Both the superconducting transition temperature and the shielding volume fraction are effectively improved with fluorine doping. The LaO$_{ 0.48}$F$_{ 0.52}$BiSe$_{ 1.93}$ sample exhibits zero-resistivity at 3.7 K, which is higher than that of the LaO$_{ 0.5}$F$_{ 0.5}$BiSe$_{ 2}$ polycrystalline sample (2.4K). Bulk superconductivity is confirmed by a clear specific-heat jump at the associated temperature. The samples exhibit strong anisotropy and the anisotropy parameter is about 30, as estimated by the upper critical field and effective mass model
Categories: cond-mat.supr-con
