Structural and magnetic study of FePt thin films as a function of the deposition temperature

The structural and magnetic properties of polycrystalline FePt thin films w ere studied by X-ray diffraction (XRD), atomic force microscopy (AFM) and v ibrating sample magnetometry (VSM). The alloys were prepared by dc magnetro n sputtering on oxidized silicon substrates with a Pt buffer layer at subst rate temperatures (T-s) varying from 300 to 600 degreesC. XRD measurements show that the increase of T-s enhances the degree of crystalline ordering a nd also the crystallographic grain size. A face centered cubic crystalline structure with (111) texture is observed. AFM images reveal the presence of a granular structure. The morphological grain size increases with the incr ease of T-s. In-plane and out-of-plane hysteresis measurements, using VSM, show that the saturation magnetization M-s decreases with increasing T-s. T he coercivity increases abruptly from 1.3 to 6.0 kOe, in the in-plane geome try, and from 1.6 to 5.6 kOe, in the out-of-plane geometry, when T-s varies from 450 to 500 degreesC.