Low-Temperature Synthesis and Magnetostructural Transition in Antiferromagnetic, Refractory Nanoparticles: Chromium Nitride, CrN

Abstract

Nanostructured chromium nitride (CrN), both a hard material and a high-melting compound that is used in the medical industry and for new energy-harvesting applications, was synthesized phase-pure for the first time via low-temperature solution synthesis in liquid ammonia. TEM analysis confirms the nanoscale character of CrN. The antiferromagnetic properties of the agglomerates of nanoparticles are discussed in comparison to literature data on the bulk materials. SQUID and DSC measurements show the transition from paramagnetic to antiferromagnetic at 258.5 K. In-situ low-temperature X-ray diffraction patterns confirm the magnetostructural phase transition at this temperature, not seen before for nanoscale CrN. This structural distortion was calculated earlier to be driven by magnetic stress. The bottom-up synthesis of CrN allows for the production of nearly oxygenand carbon-free and highly dispersed fine particles.

From MAX Phase Carbides to Nitrides: Synthesis of V2GaC, V2GaN, and the Carbonitride V2GaC1–xNx

“…An elegant way to bypass carbon is to use liquid ammonia as a solvent and nitrogen source. It has the unique property to dissolve alkaline and alkaline-earth metals into metal cations and solvated electrons. , The resulting solutions provide a high reduction potential that can be beneficially used in the synthesis of nanoparticular binary nitrides. ,− …”

Nitridation of Cr–urea complex into nanocrystalline CrN and its antiferromagnetic magnetostructural transition study

“…However, at T N , both a structural and a magnetic transformation to an AFM orthorhombic lattice is observed. 9,21,54,55…”

Metallic Iron Nanocatalysts for the Selective Acetylene Hydrogenation under Industrial Front-End Conditions

“…Synthesis of Iron Nanoparticles. The synthesis was carried out after the method of Zieschang et al 61 In order to avoid contact with oxygen or moisture during the reaction, all experiments were carried out under an argon atmosphere, including the weighing of the reactants in an argon-filled glovebox. Additionally, all glassware was heated under vacuum and purged three times with argon to remove all traces of oxygen and water.…”

“…■ RESULTS AND DISCUSSION Synthesis and Characterization. The Fe nanoparticles were synthesized via a method by Zieschang et al 61 by the reduction of FeBr 2 with sodium in liquid ammonia. After evaporation of the excess ammonia, the obtained black powder was annealed at 500 °C.…”