Direct current magnetron sputtered Ni 3 Al thin films with electron transport behaviour for superior electromagnetic shielding

Nanocrystalline Ni 3 Al thin films were deposited by direct current (DC) magnetron sputtering and studied the electron transport mechanism and electromagnetic shielding properties for the first time. The mechanism of electron transport and barrier heights were studied using scanning tunneling microscope (STM). The barrier height of Ni 3 Al thin films were decreased from 1.51 eV to 1.33 eV with sputtering power and the entire tunneling current in these films appeared to come from Schottky emission. Electromagnetic shielding properties of Ni 3 Al thin films have been studied in X-band (8.2–12.4 GHz) region and the shielding effectiveness (SE) increases with sputtering power and achieved the highest SE value 36 dB (99.96% attenuation) at 200 W sputter deposited Ni 3 Al films with 396 nm. The sputtering power alters the thickness of Ni 3 Al films thereby enhancing the electromagnetic shielding performance due to the increase of conductivity, the negative dielectric permittivity and magnetic relaxation arising from high nickel (Ni) concentration in Ni 3 Al. The results suggested that as prepared ultra-thin Ni 3 Al films can be an effective and new type of electromagnetic shielding materials. Graphical abstract