Highly crystalline cobalt nanowires with high coercivity prepared by soft chemistry

Abstract

Cobalt nanorods and wires were prepared by reduction of a cobalt salt in a liquid polyol. These particles crystallize with the hcp structure and the growth axis is parallel to the crystallographic c‐axis. The kinetic control of the growth allows to vary the mean diameter of the rods and their aspect ratio. Dumbbell like shape particles consisting of a central rod with two conical tips were also obtained. Magnetization curves of oriented wires present very high coercivity (up to 9 kOe) resulting from both a high shape anisotropy and the high magnetocrystalline anisotropy of the hcp cobalt. Micromagnetic simulations showed that the magnetization reversal is shape dependent. The conical tips of the dumbbell particles strongly contribute to the coercivity decrease and must be precluded for permanent magnet applications. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Physical properties of elongated inorganic nanoparticles

“…Recently, Viau et al used the solution-based polyol process for the preparation of highly monodisperse Co nanorods [418]. Well-crystallized hcp-Co nanorods of different aspect ratios were obtained, and the c axis of the lattice was observed to be parallel to the growth direction of the nanorods (Fig.…”

Synthesis of nanocrystalline Co–Ni alloys by precursor approach and studies on their magnetic properties

“…Typical histograms (Fig. 6) polyol reduction, sodium hydroxide present in ethylene glycol is known to control the shape of cobalt and cobalt-nickel alloys [36,51]. Fig.…”

Laser Alloying of Co Nanorods and Al Nanoparticles in a Liquid

“…[20] The Co nanorod powder is black and efficiently absorbs visible radiation. The mass concentration of the initial Al nanoparticles created by the electrical explosion technique (commercial name:" Alex") was two times higher than the content of Co nanorods obtained by chemical polyol synthesis using Ru as ac atalyst.…”

“…The polyol method involves the reduction of am etal salt precursor by ap olyol, ac ompound containing multiple hydroxyl groups. [20] The Co nanorod powder is black and efficiently absorbs visible radiation. Laser exposure of the suspension is accompanied by plasma formation, whose radiation is efficiently absorbed by the Co component of the suspension.…”