%0 Journal Article %T One-step synthesis of KxFe2-ySe2 single crystals for high critical current density %A Toshinori Ozaki %A Hiroyuki Takeya %A Hiroyuki Okazaki %A Keita Deguchi %A Satoshi Demura %A Yasuna Kawasaki %A Hiroshi Hara %A Tohru Watanabe %A Takahide Yamaguchi %A Yoshihiko Takano %J Physics %D 2012 %I arXiv %R 10.1209/0295-5075/98/27002 %X We have established a simple process that allows for the one-step synthesis of KxFe2-ySe2 single crystals, which exhibit high critical current density Jc. The post annealing and quenching technique has improved the homogeneity of as-grown crystals, resulting in full shielding of the external magnetic field. The quenched crystals show a superconducting transition at Tconset = 32.9 K and Tczero = 32.1 K. The upper critical fields \mu_{0}Hc2(0) for H//ab and H//c are estimated to be ~206 and ~50 T, respectively. The critical current densities Jc for H//ab and H//c reach as high as 1.0\times10^{5} and 3.4\times10^{4} A/cm2 at 5 K. Furthermore, Jc exhibits a high field performance and a significantly weak temperature dependence up to 5 T, suggesting strong pinning. These results demonstrate that KxFe2-ySe2 would be a promising candidate material for practical applications. %U http://arxiv.org/abs/1202.3837v3