{\alpha}-FeAs-free SmFeAsO1-xFx by low temperature sintering with slow cooling

• Published in: arXiv.org
• Main Authors: Fujioka, Masaya, Saleem James Denholme, Ozaki, Toshinori, Okazaki, Hiroyuki, Deguchi, Keita, Demura, Satoshi, Hara, Hiroshi, Watanabe, Tohru, Takeya, Hiroyuki, Yamaguchi, Takahide, Kumakura, Hiroaki, Takano, Yoshihiko
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 07.08.2013
• Subjects: Cooling; Cooling effects; Fluorine; Physics - Superconductivity; Sintering; Superconductivity; Temperature
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1303.1309

We obtained amorphous-FeAs-free SmFeAsO1-xFx using a low temperature sintering with slow cooling. SmFeAsO1-xFx is sintered at 980 {\deg}C for 40 hours and cooled slowly down to 600 {\deg}C. The low temperature sintering suppresses the formation of amorphous FeAs, and the slow cooling introduces much fluorine into SmFeAsO1-xFx. The superconductivity of this sample appears at 57.8 K and the superconducting volume fraction reaches 96 %. To study the change of fluorine concentration during the cooling process, samples are quenched by water at 950 {\deg}C, 900 {\deg}C, 850 {\deg}C, 800 {\deg}C, 750 {\deg}C and 700 {\deg}C. It is found that fluorine is substituted not only at the maximum heating temperature but also during the cooling process. The low temperature sintering with slow cooling is very effective to obtain a homogeneous SmFeAsO1-xFx with high fluorine concentration.