Influence of Ni content on the microstructure and magnetic and magneto-optical properties of sputtered (Co1-xNix)Pt-3 alloy films

摘要

Influence of Ni content on the microstructure and magnetic and magneto-optical ( MO) properties of sputtered (Co1-xNix)Pt-3 alloy films has been investigated by means of Kerr spectrometer, Kerr hysteresis looper, X-ray difractometer (XRD), and atomic force microscopy (AFM). On the whole, the addition of Ni to the CoPt3 alloy film simultaneously decreases the Curie temperature T-C and the Kerr rotation angle theta(K), but the decrease of T-C with Ni content is more visible. When the Ni content x is increased from 0 to 0.33, T-C decreases from 273 degrees C to 233 degrees C, whereas the decrease of theta(K) is quite limited and the film still preserves a strong perpendicular magnetic anisotropy (PMA) and a high coercivity, indicating that the (Co1-xNix)Pt-3 alloy film with x = 0.33 can be used for practical MO applications. Further increase of Ni content decreases the theta(K) significantly and destroys the PMA. XRD and AFM studies show that adding a small amount of Ni in the CoPt3 alloy film will promote the growth of grains and roughen the film surface, and thus enhance the coercivity of the film. We observe also that both the coercivity and PMA are not sensitive to the (111) preferred orientation of the (Co1-xNix)Pt-3 alloy.