在四方晶系的Li取代效應與LixFeTe1-ySey的超導性研究 (x = 0.1, 0.2; 0 ≤ y ≤ 0.7)

Effects of Li-doping on Tetragonal Phase and Superconductivity in LixFeTe1-ySey (x = 0.1, 0.2; 0 ≤ y ≤ 0.7)

陳奕瑞(YI-JUI CHEN)

指導教授 ： 李文新

國立中正大學/理學院/物理學系/碩士(2016年)

摘要

本研究根據X光粉末繞射圖與晶體結構數據顯示，Li0.1FeTe1-ySey和Li0.2FeTe1-ySey (0 ≤ y ≤ 0.6)二系列化合物保有Fe1+xTe tetragonal單相結構。說明了額外的Li在Li0.1FeTe1-ySey和Li0.2FeTe1-ySey兩系統能夠穩定PbO-type結構。
磁化強度測量結果顯示，Li0.1FeTe1-ySey和Li0.2FeTe1-ySey兩系統所有超導樣品的臨界磁場Hc1小於1.0 Oe。此二系列之樣品，當Li = 0.1，0.3 y 0.7，和Li = 0.2，0.2 ≤ y ≤ 0.6時，有著明顯的順磁到超導反磁相變化，其中組成比例Li0.2FeTe0.6Se0.4的樣品具有較高Tc,onset，大約為11.5 K。

關鍵字

鐵基超導 ； 鋰鐵硒碲 ； 額外的鋰

並列摘要

In this work, as judged by X-ray-powder patterns and crystallographic data, the primitive tetragonal structure of Fe1+xTe is retained in both Li0.1FeTe1-ySey and Li0.2FeTe1-ySey systems up to the solubility limit near x = 0.6. The excess Li in both Li0.1FeTe1-ySey and Li0.2FeTe1-ySey systems is found to be able to stabilize the PbO-type crystal structure.
Static magnetization measurements indicated that all samples with superconducting properties in both Li0.1FeTe1-ySey and Li0.2FeTe1-ySey systems have small lower critical field Hc1 less than 1.0 Oe. Clear phase transition from paramagnetic to perfect diamagnetic state and Tc,onset around 11.5 K appear in the sample with composition Li0.2FeTe0.6Se0.4.

並列關鍵字

Fe-based superconductivity ； LixFeTe1−ySey ； Excess Li

參考文獻

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