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

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 nano particles 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 oxygen and carbon-free and highly dispersed fine particles.