Cr additive effects on the nanostructure, magnetic properties, and ordering kinetics of FePtCu thin films

In this study, the (FePt)94-xCu6Crx (x = 0, 6.54, 8.33, 11.11) alloy films were prepared by sputtering and then the effects of Cr content and heat treatment on the nanostructures and magnetic properties of polycrystalline FePtCu films are examined. After adding Cr atoms to FePtCu films, the surrounding Cr layer of the grain limited grain growth of (FePt)94−xCu6Crx (x = 0, 6.54, 8.33, 11.11) alloy films, even when those films had been annealed at temperatures as high as 600 °C. The differential scanning calorimetry traces revealed that the addition of Cr atoms enhanced the activation energy of ordering from 87 kJ mol−1 for the (FePt)94-xCu6 film to 264 kJ mol−1 for the (FePt)94-xCu6Crx film (x = 6.54). The (FePt)94-xCu6Crx (x = 6.54) film displayed a coercive force of 12.8 kOe and a magnetization of 658 emu cc−1.