Toshinori Ozaki, Hiroyuki Takeya, Keita Deguchi, Satoshi Demura, Hiroshi Hara, Tohru Watanabe, Denholme Saleem James, Hiroyuki Okazaki, Masaya Fujioka, Takahide Yamaguchi, Yoshihiko Takano
We report the evolution of superconductivity and the phase diagram of the KxFe2-ySe2-zTez (z=0-0.6) crystals grown by a simple one-step synthesis. No structural transition is observed in any crystals, while lattice parameters exhibit a systematic expansion with Te content. The Tc exhibits a gradual decrease with increasing Te content from Tconset = 32.9 K at z = 0 to Tconset = 27.9 K at z = 0.5, followed by a sudden suppression of superconductivity at z = 0.6. Upon approaching a Te concentration of 0.6, the shielding volume fraction decreases and eventually drops to zero. Simultaneously, hump positions in r-T curve shift to lower temperatures. These results suggest that isovalent substitution of Te for Se in KxFe2-ySe2 crystals suppresses the superconductivity in this system.
View original:
http://arxiv.org/abs/1209.2002
No comments:
Post a Comment