Influence of Ni content on the microstructure and magnetic andmagneto-optical properties of sputtered (Co1-xNix)Pt3 alloyfilms

Influence of Ni content on the microstructure and magnetic andmagneto-optical (MO) properties of sputtered (Co1-xNix)Pt3alloy films has been investigated by means of Kerr spectrometer, Kerrhysteresis looper, X-ray diffractometer (XRD), and atomic force microscopy(AFM). On the whole, the addition of Ni to the CoPt3 alloy filmsimultaneously decreases the Curie temperature TC and the Kerr rotationangle θK, but the decrease of TC with Ni content is morevisible. When the Ni content x is increased from 0 to 0.33, TCdecreases from 273 ○C to 233 ○C, whereas the decrease of θK is quite limited and the film still preserves a strongperpendicular magnetic anisotropy (PMA) and a high coercivity, indicatingthat the (Co1-xNix)Pt3 alloy film with x=0.33 can be usedfor practical MO applications. Further increase of Ni content decreases the θK significantly and destroys the PMA. XRD and AFM studies showthat adding a small amount of Ni in the CoPt3 alloy film will promotethe growth of grains and roughen the film surface, and thus enhance thecoercivity of the film. We observe also that both the coercivity and PMA arenot sensitive to the (111) preferred orientation of the (Co1-xNix)Pt3 alloy films.