Using radio frequency (rf) sputtering, we have prepared in presence of a static magnetic field, ferromagnetic thin films of composition (Co93Zr7)100−yREy(RE=Nd,Pr,Dy,Tb... a magnetic rare earth element). This study was performed for small amounts of RE substitution (0<y<3). These films exhibit attractive soft magnetic properties similar to CoZr alloys: low coercivity (Hc∼1 Oe), and a high saturation induction (4&pgr;Ms≳10 kG). A low in‐plane uniaxial anisotropyHkwas induced, whose magnitude depends upon the composition and the preparation parameters. Substitution by RE atoms affects essentially the &mgr; frequency‐response. Depending on the nature, the concentration of RE atoms and on the value ofHk, a high relative rotational permeability &mgr; (&mgr;’∼500–3000 at frequencies up to 500 MHz) was obtained. Also depending on RE and ony, high &mgr;‘(&mgr;‘∼400–3000 at &ngr;∼1 GHz) distributed over a very broad frequency range (&Dgr;&ngr;∼500–2500 MHz) could be measured.