ANNEALING EFFECT OF SURFACE MAGNETIC-PROPERTIES IN AMORPHOUS CO1-XTIXTHIN-FILMS

For amorphous Co1-xTix(X=0.13, 0.16, 0.21 at.%) thin films deposited b y DC magnetron sputtering method ferromagnetic resonance experiments h ave been used to investigate the dependence of surface magnetic proper ties in according to annealing temperatures(150 similar to 225 degrees C). Spin wave resonance spectra for all annealing temperatures consis t of several volume modes and one(or two) surface mode. It is suggeste d that both surfaces of the film have a perpendicular hard axis to the film plane(negative surface anisotropy). Also, the surface anisotropy K-s2 at substrate-film interface is varied slowly from -0.11 to -0.25 erg/cm(2) and the surface anisotropy K-s1 at film-air interface is va ried from 0.16 to -0.53 erg/cm(2) with increasing annealing temperatur es. We conjecture that the variation of surface anisotropy K-s1 is due to the increase of Co concentration resulted from Ti oxidation for lo w temperature annealing(150 similar to 200 degrees C) and the diffusio n of Co atoms near the film surfaces for high temperature annealing(22 5 similar to 250 degrees C).