Various Ni-doped carbon (C：Ni) thin films were fabricated using different Ni target power densities by unbalanced magnetron sputtering (UBM). The effects of target power density on the structural, physical, surface, and electrical properties of C：Ni films were investigated. The UBM C：Ni thin films exhibited uniformly smooth surfaces. The rms surface roughness and friction coefficient values of the C：Ni films decreased with the increase in target power density. The physical properties of the films such as hardness and elastic moduli increased while their electrical properties such as resistivity decreased with the increase in the target power density. These results show that an increase of the power density leads to an increase in the proportion of Ni and nanocrystallization of the amorphous carbon film; this contributes to the changes observed in the physical and electrical characteristics.

In this research, the structural, physical and electrical characteristics of Ni-Fe core chosen tominimize the errors of the Hall current sensors were investigated and Hall current sensor using Ni-Fecore was fabricated. In the result, the fabricated Ni-Fe sample exhibited the maximum hardness about29.5 GPa and the low friction coefficient about 0.35, and electrical resistivity over 90 mOhm·cm. And alsoHall current sensor using the fabricated Ni-Fe core showed linear current-voltage properties for DCcurrent at 25℃ temperature.