The structural and magnetic properties of Co_0.9Pd_0.1 thin films grown under vacuum by physical vapor deposition (PVD) on Si (100) are reported. Before evaporation the pressure in the chamber was 10^-7 mbar. During evaporation, the base pressure was better than 10^-6 mbar. The thicknesses of the samples were measured with a DEKTAK 150 profilometer and ranges from 50 to 220 nm, The atomic concentration was determined by EDX measurements, microscopic characterizations of the films were done with X-Ray diffraction (XRD) and infer that all the samples were polycristalline with an hcp structure. The hysteresis loops were performed by means of vibrating sample magnetometer (VSM) and infer that all the samples present a planar ferromagnetic anisotropy. The thickness dependence of in plane squareness showed a similar trend with corresponding coercivity. All these results will be presented and discussed.