title: Super-stable ultrafine beta-tungsten nanocrystals with metastable phase and related magnetism.
abstract: 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.
authors.affiliation: 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.
authors.forename: J
authors.initials: J
authors.lastname: Xiao
authors.forename: P
authors.initials: P
authors.lastname: Liu
authors.forename: Y
authors.initials: Y
authors.lastname: Liang
authors.forename: H B
authors.initials: HB
authors.lastname: Li
authors.forename: G W
authors.initials: GW
authors.lastname: Yang
mesh_terms: D003460:Crystallization / Q000379:methods; D060526:Magnetic Fields; D008422:Materials Testing; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure*; D008968:Molecular Conformation; D010316:Particle Size; D044367:Phase Transition; D013499:Surface Properties; D014414:Tungsten / Q000737:chemistry*
chemical_list: D014414:Tungsten