Origin of the Higher-Tc Phase in the KxFe2−ySe2 System

• DOI: 10.7566/jpsj.85.044710
• Publication Date: 2016-03-31T01:26:21Z
• Authors: Masashi Tanaka; Yusuke Yanagisawa; Saleem J. Denholme; Masaya Fujioka; Shiro Funahashi; Yoshitaka Matsushita; Nobuo Ishizawa; Takahide Yamaguchi; Hiroyuki Takeya; Yoshihiko Takano
• Keywords: Crystal (programming language); Texture (cosmology); Transition temperature

Single crystals of KxFe2−ySe2 are prepared by quenching at various temperatures. The obtained higher temperatures have a surface morphology with mesh-like texture. They show sharp superconducting transition Tc ∼ 32 K large shielding volume fraction. On the other hand, without an onset ∼44 and zero resistivity approximately ∼33 K, they possess island-like regions on larger amount Fe incorporation. In situ high-temperature single-crystal X-ray diffraction measurements tell us Fe-vacancy-ordered phase is generated temperature region around 270 °C via iron diffusion. generation this may become driving force for growth higher-Tc phase. superconductivity attributed to metallic no vacancy.