Study on microstructural characterization and ferromagnetic resonance in sputtered Co/V multilayers

The structure and magnetic properties of a series of rf sputtered [Co(1.5 nm)/V(d(v))](20)(0.5 nm less than or equal to d(v) less than or equal to 4 nm)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 fee 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 4 pi M-eff 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.