Structural and Magnetic Properties of FePt-C Nanocomposite Films

Nanocomposite FePt-C thin films were prepared by a pulsed filtered vacuum arc deposition technique. The films were characterized by non-Rutherford backscattering spectrometry, x-ray diffraction, and magnetic force microscopy. The dependence of magnetic properties against annealing temperature was studied by using a vibrating sample magnetometer. Both x-ray diffraction and magnetic force microscopy analyses confirmed the formation of nano-crystallites of face-centred-tetragonal phase of FePt in the carbon matrix after annealing at a sufficiently high temperature. For the film with a composition of (Fe_0.55Pt_0.45)_0.78C_0.22, the coercivity and the grain size were observed to increase with increasing annealing temperature, up to a value of 3.5 kOe at an annealing temperature of 650°C, and with a grain size about 10.5 nm.