Non-magnetic hexagonal nanocrystalline ni films grown by radio frequency magnetron sputtering.
Nanoscale Ni films in the thickness range 15-500 nm were grown on various substrates, such as amorphous glass, single crystalline silicon and sapphire, and polycrystalline alumina, at a temperature of about 350 K by radio frequency magnetron sputtering. It is demonstrated, via X-ray diffraction and high-resolution transmission electron microscopy, that there is an Ar-gas pressure window that favors the growth of stable single-phase hexagonal nanocrystalline Ni films regardless of the film thickness and the kind of the substrate. At lower or higher Ar pressures the films grow in the regular face centered cubic phase of Ni. The structural habits are attributed to differences in the kinetic energy of the Ni atoms impinging on the substrates. Superconducting quantum interference device magnetometry measurements reveal that the hexagonal films show zero magnetic response down to liquid Helium temperature. This result is discussed with respect to earlier first principle calculations and to experimental results on Ni nanoparticles.
Poulopoulos
Panagiotis
P
Materials Science Department, University of Patras, 26500 Patras, Greece.
Kapaklis
Vassilios
V
Politis
Constantin
C
Schweiss
Peter
P
Fuchs
Dirk
D
D003460:Crystallization / Q000379:methods*; D006358:Hot Temperature; D046911:Macromolecular Substances / Q000737:chemistry; D008280:Magnetics; D008422:Materials Testing; D008567:Membranes, Artificial; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods; D009532:Nickel / Q000737:chemistry* / Q000528:radiation effects*; D010316:Particle Size; D011846:Radio Waves; D013499:Surface Properties
D046911:Macromolecular Substances; D008567:Membranes, Artificial; D009532:Nickel