Well-isolated L1 0 FePt-SiN x-C nanocomposite films with large coercivity and small grain size

Abstract

FePt-SiN x-C films on TiN/CrRu/glass substrate with large coercivity, (001) texture, and small isolated grains were obtained by co-sputtering FePt, Si 3N 4, and C targets at 380°C. It was found that when C was doped into the FePt-SiN x films, the out-of-plane coercivity increased while the small in-plane coercivity remained unchanged. Grain size decreased and grain size distribution became more uniform with increasing the C doping concentration. The x-ray photoelectron spectroscopy (XPS) depth profile showed a uniform depth distribution of Si in the FePt layer. The Si2p XPS spectrum implied the existence of Fe-Si bonds, indicating that SiN x was located at the FePt grain boundaries and was stable against diffusion to the surface, thus favoring grain isolation. Well-isolated FePt (001) granular films with coercivity higher than 21.5 kOe and an average grain size of 5.6 nm were obtained by doping 40 vol. of SiN x and 20 vol. of C. © 2012 American Institute of Physics.