Synthesis and Characterization of NiCr Self-assembled Nanorings

Formation of NiCr nanorings out of 2-3 nm NiCr nanoparticles prepared by DC magnetron sputtering with inert gas condensation is reported. An RF quadrupole mass filter has been used to get the particle size distribution and control the particle size in the plasma stream of grown material. The depositions are made on silicon substrates at room temperature under a helium and argon atmosphere of varying composition. By optimizing the He-Ar composition, magnetron power and the condensation zone, the particle size distribution is narrowed. Magnetic characterization determines that every single nanoparticle possesses a single magnetic domain that influenced their arrangement on the substrate. These arrangements were particularly in ring like structures. Particles join together while being deposited to form rings with a ~100 nm diameter. Particle density and agglomeration phenomena depend on the substrate’s time of exposure to the NiCr nanoparticle source coming from the target.