A Solution for Solution-Produced 尾-FeSe: Elucidating and Overcoming Factors that Prevent Superconductivity

详细信息    查看全文

• 作者：Joshua T. Greenfield ; Saeed Kamali ; Kathleen Lee ; Kirill Kovnir
• 刊名：Chemistry of Materials
• 出版年：2015
• 出版时间：January 27, 2015
• 年：2015
• 卷：27
• 期：2
• 页码：588-596
• 全文大小：611K
• ISSN：1520-5002

文摘

A new low-temperature solvothermal synthesis of superconducting 尾-FeSe has been developed using elemental iron and selenium as starting materials. We have shown that syntheses performed in aerobic conditions resulted in the formation of nonsuperconducting antiferromagnetic 尾-FeSe, whereas syntheses performed in ultra-dry and oxygen-free conditions produced superconducting 尾-FeSe. Detailed characterization of both types of samples with magnetometry, resistivity, M枚ssbauer spectroscopy, synchrotron X-ray and neutron powder diffraction, and pair-distribution function analysis uncovered factors that trigger the loss of superconductivity in 尾-FeSe. Vacancies in the iron sublattice and the incorporation of disordered oxygen-containing species are typical for nonsuperconducting antiferromagnetic samples, whereas a pristine structure is required to preserve superconductivity. Exposure to ambient atmosphere resulted in the conversion of superconducting samples to antiferromagnetic ones. This synthetic method creates new possibilities for soft chemistry approaches to the synthesis and modification of iron-based superconductors.