Influence of annealing tempreture on the structural and magnetic properties of nanostructured FePt thin films

The main goal of this study is to investigate the structural and magnetic properties of FePt thin film with respect to the annealing tempreture. The FePt thin films were deposited by RF magnetron sputtering on Corning glass substrates at a room temperature. Base pressure was kept constant at 2 10-7 Torr. The Ar pressure was mTorr. Thin films was sputtered with an rf power supply at 110 W, yelding a rate of 6. After deposition, samples were annealed in the range of 450-650℃ for 30 min. Phase identification of thin films was performed using X-ray diffraction (XRD). With employing SEM, the size and uniformity of grains were studied. The morphology and surface roughness was also determined using an atomic force microscopy (AFM). Moreover magnetic properties of annealed thin films were evaluated using a vibrating sample magnetometer (VSM). XRD results showed that the ordered FePt structure is formed at 450℃ and with an increase in annealing temperature, ordering parameter were enhanced and at 650℃ reaches at its maximum value. On the other hand surface roughness and grain size increased with increasing temperature. The topography of the film consists of two main kinds of grain: those with a needlelike shape and those in form of platelets. According to the hysteresis loops, hard ferromagnetic FePt phase is formed at 550 ℃ due to high order parameter. However the best structural and magnetic properties were obtained at 650℃.