Fe-Zr-N films: Effect of nitrogen content and nitrogen-to-zirconium concentration ratio on saturation induction E.N. Sheftel, E.V. Harin ⇑ Baikov Institute of Metallurgy and Materials Science RAS, Leninsky pr. 49, Moscow 119334 Russia article info Article history: Received 24 May 2018 Received in revised form 21 June 2018 Accepted 24 June 2018 Available online 25 June 2018 Keywords: Crystal structure Deposition Magnetic materials Nanocrystalline materials Thick films X-ray techniques abstract Films Fe x Zr 9 N y (x = 86  77, y = 5  14, at.%) prepared by rf reactive magnetron sputtering were used to study the effect of nitrogen content and nitrogen-to-zirconium concentration ratio on their phase com- position and saturation induction B s . It was shown that the films containing 9 at.% Zr and characterized by the nitrogen-to-zirconium ratio 1 have the two-phase structure, which forms during deposition and comprises a-Fe(N) solid solution and ZrN nitride. The B s dependence on the nitrogen content in a-Fe (N) solid solution was found to be linear. Ó 2018 Elsevier B.V. All rights reserved. 1. Introduction Nanocrystalline Fe-Zr-N system films prepared by magnetron sputtering can provide the unique combination of magnetic and mechanical properties, which exceed those of majority of soft mag- netic materials and are required for their application in advanced miniature microelectronic devices. The chemical composition of these films comprises 10–12 at.% Zr and is characterized by the ratio C N /C Zr = 1 (where C N and C Zr are the nitrogen and zirconium concentration, at.%, respectively), which corresponds to the com- position range of eutectic alloys of the equilibrium quasi-binary Fe-ZrN phase diagram [1]. Previous studies [2–6] showed that nitrogen, being the alloying element, determines the phase and structural state of the films to a certain degree. Under suitable deposition conditions, depending on the nitrogen content and C N /C Zr ratio, either single phase or phase combination, such as amorphous, a-Fe(N) solid solution supersaturated with nitrogen, ZrN and Fe x N y nitrides form. So the phase composition of the films determines their saturation induction B s . The aim of the present study is to estimate the effect of nitrogen content and C N /C Zr ratio in the Fe x Zr 9 N y (x = 86  77, y = 5  14, at.%) films on their B s . 2. Material and methods The chemical composition of the studied films (about 1 lm thick) corresponds to the formula Fe x Zr 9 N y (x = 86  77, y = 5  14, at.%). They were prepared by rf reactive magnetron sputtering and subsequently subjected to annealing in vacuum 210 6 Torr at temperatures from 300 to 750 °C using 30-, 60-, 120-, and 180-min holdings. Deposition conditions and detailed data on the phase composition and structure of the films, which were studied by X-ray diffraction (XRD), are available in our works [7–8]. The chemical composition of the films was determined in vac- uum 10 5 Torr using a scanning electron microscope equipped with an X-ray energy-dispersion analyzer. B s of the films was mea- sured at room temperature in applied magnetic fields up to 7 kOe using a vibrating-sample magnetometer. The results of the mea- surements are given in Table 1. 3. Results and discussion According to the data given in Table 1, depending on the nitro- gen content and C N /C Zr ratio, two two-phase states can be formed; these are (1) the nanocrystalline ferromagnetic phase (the grain size is 6–23 nm), which is an a-Fe-based solid solution, plus ferro- magnetic Fe-based amorphous (in XRD terms) phase and (2) nanocrystalline a-Fe-based phase (with a grain size of 4–12 nm) plus nanocrystalline nonferromagnetic ZrN phase. https://doi.org/10.1016/j.matlet.2018.06.110 0167-577X/Ó 2018 Elsevier B.V. All rights reserved. ⇑ Corresponding author. E-mail address: harin-eugene@ya.ru (E.V. Harin). Materials Letters 229 (2018) 36–39 Contents lists available at ScienceDirect Materials Letters journal homepage: www.elsevier.com/locate/mlblue