We report a chemical method to synthesize size-controllable SmCo5 nanoparticles (NPs) and to stabilize the NPs against air oxidation by coating a layer of N-doped graphitic carbon (NGC). First 10 nm CoO and 5 nm Sm2O3 NPs were synthesized and aggregated in reverse micelles of oleylamine to form SmCo-oxide NPs with a controlled size (110, 150, or 200 nm). The SmCo-O NPs were then coated with polydopamine and thermally annealed to form SmCo-O/NGC NPs, which were further embedded in CaO matrix and reduced with Ca at 850 °C to give SmCo5/NGC NPs of 80, 120, or 180 nm, respectively. The 10 nm NGC coating efficiently stabilized the SmCo5 NPs against air oxidation at room temperature or at 100 °C. The magnetization value of the 180 nm SmCo5/NGC NPs was stabilized at 86.1 emu/g 5 days after air exposure at room temperature and dropped only 1.7% 48 h after air exposure at 100 °C. The stable SmCo5/NGC NPs were aligned magnetically in an epoxy resin, showing a square-like hysteresis behavior with their H c reaching 51.1 kOe at 150 K and 21.9 kOe at 330 K and their Mr stabilized at around 84.8 emu/g. Our study demonstrates a new strategy for synthesizing and stabilizing SmCo5 NPs for high-performance nanomagnet applications in a broad temperature range.

The authors demonstrate that individual nanotips ͑W 18 O 49 ͒ may be laser welded onto the supporting microtip. The nanotip-microtip assembly can be handheld or ready for further manual manipulation, and thus is very useful for individual nanowire's characterization, selection, and applications in nanoprobe analysis, nano-optical and nanoelectronic devices, and biostudy. Well mechanical and electrical connections are shown between the nanotip-microtip. Field emission characterization shows that the welded nanotip is a promising candidate for point electron source application.

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Gas bubbles are easily accessible and offer many unique characteristic properties of a gas/liquid two-phase system for developing analytical methods. In this minireview, we discuss the newly developed analytical strategies...