Investigation of Fe–Si–N films as magnetic overcoat for high density recording disk drives

Abstract

A 50-nm-thick Fe–Si–N films were deposited via reactive magnetron cosputtering of independent Fe and Si targets, in Ar/N2 gas mixture, under different dc Fe target power conditions. Magnetic properties, mechanical hardness and tribological properties were characterized as a function of the Fe target power by magnetometry, nanoindentation, and nanoscratch testing, respectively. Deposited samples were found to be ferromagnetic with a coercivity of approximately 20 Oe and a saturation magnetization increasing from 200 to 1100 emu/cm3 as a function of Fe sputter power, i.e., values typical of soft magnetic materials. The mechanical hardness was found to be between 50% and 70% of the hardness of a pure SiNx film. Nanotribological properties of films deposited with a Fe target power ≥80 W degraded rapidly.