Structure-Induced Ferromagnetic Stabilization in Free-Standing Hexagonal Fe1.3Ge Nanowires

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• 作者：Hana Yoon ; Alex Taekyung Lee ; Eun-Ae Choi ; Kwanyong Seo ; Nitin Bagkar ; Jaehun Cho ; Younghun Jo ; K. J. Chang ; Bongsoo Kim
• 刊名：Journal of the American Chemical Society
• 出版年：2010
• 出版时间：December 15, 2010
• 年：2010
• 卷：132
• 期：49
• 页码：17447-17451
• 全文大小：268K
• 年卷期：v.132,no.49(December 15, 2010)
• ISSN：1520-5126

文摘

Single-crystalline free-standing hexagonal Fe_1.3Ge nanowires (NWs) are synthesized for the first time using a chemical vapor transport process without using any catalyst. Interestingly, Fe_1.3Ge NWs are found to be ferromagnetic at room temperature, while bulk Fe_1.3Ge has the lower critical temperature of 200 K. We perform first-principles density functional calculations and suggest that the observed strong ferromagnetism is attributed to the reduced distances between Fe atoms, increased number of Fe−Fe bonds, and the enhanced Fe magnetic moments. Both experimental and theoretical studies show that the magnetic moments are enhanced in the NWs, as compared to bulk Fe_1.3Ge. We also modulate the composition ratio of as-grown iron germanide NWs by adjusting experimental conditions. It is shown that uniaxial strain on the hexagonal plane also enhances the ferromagnetic stability.