The structure and magnetic properties of a series of rf sputtered [Co(1.5nm)/V(dV)]20(0.5nm≤dV≤4nm)multilayers have been studied.The multilayers structure is found by X-ray diffraction,cross-section transmission electron microscopy,and high-resolution transmission electron microscopy to be polycrystalline with small individual columnar grains and has fairly strong fcc Co(111)and bcc V(110) texture in the film growth direction.The structural characterizations also show composition-modulated structure and severely alloyed effect.Ferromagnetic resonance measurements show relatively small g factors and 4π Meff values,which also indicates that multilayers are severely alloyed.Complicated spin wave resonance spectra were observed and analyzed.The evaluated small interlayer coupling constant shows the effect of weak exchange coupling between Co layers across V spacers.