Effect of magnetron sputtering conditions and subsequent annealing on the structure and magnetic properties of Fe97−x Zr3N x films

Abstract

X-ray diffraction analysis was used to study the structure of Fe97−xZr3Nx thin films produced under different conditions of rf magnetron sputtering (on rotary and stationary substrates) and subsequent annealing. Either a single-phase structure, namely, a supersaturated bcc α-(FeN) solid solution, or a mixed structure that consists of two crystalline phases, such as a supersaturated bcc α-Fe(N) solid solution and an fcc Fe4N nitride, and a Fe-based amorphous phase were shown to be formed in films deposited on either stationary or rotating substrate, respectively. As the annealing temperature increases, the content of nitrogen in the bcc phase decreases; the grain size of the bcc phase in the films deposited on rotating and stationary substrates increases from 8 to 14 nm and from 10 to 30 nm, respectively; the amount of the Fe4N phase increases. The results of the study of the magnetic properties of the films are reported. The maximum saturation induction Bs reached is 1.8–1.9 T; the minimum coercive force Hc is 1 Oe. The optimum combination of the magnetic properties (Bs = 1.8–1.9 T and Hc = 1.5–1.8 Oe) is observed for the films deposited on the rotating substrate and subsequently annealed at 400°C.