State Key Laboratory of Optoelectronic Materials and Technologies, Institute of Optoelectronic and Functional Composite Materials, Nanotechnology Research Center, School of Physics & Engineering, Sun Yat-sen University, Guangzhou 510275, Guangdong, PR China.
Nanoscale. 2013 Feb 7;5(3):899-903. doi: 10.1039/c2nr33484d. Epub 2012 Dec 20.
Ultrafine tungsten nanocrystals (average size of 3 nm) with a metastable phase (beta-tungsten with A15 structure, β-W) have been prepared by laser ablation of tungsten in liquid nitrogen. The as-prepared metastable nanocrystals exhibited super-stablity, and can keep the same metastable structure over a period of 6 months at room temperature. This super-stability is attributed to the nanosized confinement effect of ultrafine nanocrystals. The magnetism measurements showed that the β-W nanocrystals have weak ferromagnetic properties at 2 K, which may arise from surface defects and unpaired electrons on the surface of the ultrafine nanocrystals. These findings provided useful information for the application of ultrafine β-W nanocrystals in microelectronics and spintronics.
超细钨纳米晶（平均尺寸为 3nm）具有亚稳相（具有 A15 结构的β-钨，β-W），通过激光烧蚀液态氮中的钨制备而成。所制备的亚稳纳米晶表现出超稳定性，在室温下可保持相同的亚稳结构长达 6 个月。这种超稳定性归因于超细纳米晶的纳米限域效应。磁性测量表明，β-W 纳米晶在 2K 时具有弱铁磁性，这可能源于超细纳米晶表面的表面缺陷和未配对电子。这些发现为超细 β-W 纳米晶在微电子学和自旋电子学中的应用提供了有用的信息。
