Keywords: nanocontacts, ballistic magnetoresistance, BMR, microfabrication, nanotechnology, metallic nickel films, focused ion beam milling, lithography, oxidisation
An approach to fabricate pure metallic Ni-Ni and metallic oxide Ni-NiO-Ni nanocontacts by repeatable microfabrication method
Metallic nickel films of thickness between 3 nm and 50 nm on SiO2/Si substrate were first deposited by magnetron sputtering system. T-shape nanocontacts for both pure metallic Ni-Ni and metallic oxide Ni-NiO-Ni were then patterned by electron-beam and ultra-violet lithography combined with focused ion beam milling method. The dimension of each of the nanocontacts along the horizontal direction with the thin film was systematically changed from 10 nm to 50 nm. Different oxidisation methods were used to investigate the influence of oxygen on transport properties upon the metallic oxide Ni-NiO-Ni nanocontacts. Magnetoresistances were observed lower than 1% at room temperature in both series. No evidence was found of large ballistic magnetoresistance based on such repeatable microfabrication methods.