Applied Stress-Assisted Growth of Single Crystal gamma-Fe2O3 Nanowires

作者：Lu, Lan; Hong, Ligen; Chu, Yi; Pan, Huayong; Huang, Shaoyun; Xing, Yingjie^*; Xu, Hongqi^*

来源：Nanomaterials, 2018, 8(12): 1037.

DOI：10.3390/nano8121037

• nanowires
• synthesis
• novel phenomena
• maghemite
• growth model

It is difficult to obtain gamma-Fe2O3 nanostructures by heating iron substrate in ambient conditions because gamma-Fe2O3 is less thermodynamically stable than alpha-Fe2O3. In this work, we synthesize gamma-Fe2O3 nanowires by heating iron particles under an external force. The stacking style of iron and oxygen ions under a strong shearing stress tends to adopt the gamma-Fe2O3 structure regardless of the thermodynamic restriction. These gamma-Fe2O3 nanowires exhibit a clear ferromagnetic property. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) measurements confirm that gamma-phase structure appears only under the applied external force during the heating period. A window of the magnitude of the external force is found to help the nanowire growth on iron particles. The growth mechanism of gamma-Fe2O3 nanowires other than alpha-Fe2O3 under the external force is discussed and an applied stress-assisted growth model is proposed. This work presents an easy approach to produce ferromagnetic iron oxide nanowires on a large scale.

• 出版日期2018-12
• 单位北京大学