Correlation between GMR and nonlinear magneto-optical Kerr effect in granular films

Abstract

Co x Ag 1− x and (CoFe) x (Ag 2O 3) 1− x nanogranular films exhibiting giant magnetoresistance (GMR) are studied using optical second-harmonic generation (SHG) and nonlinear magneto-optical Kerr effect (NOMOKE). A noticeable SHG azimuthal anisotropy and a low level of the diffuse second-harmonic (SH) signal indicate a high degree of orientational ordering of magnetic granules in the film plane. Nonmonotonous dependences on x are observed for the intensity of specular and diffuse SH components and for the NOMOKE magnetic contrast. The latter attains a local maximum, for each film type, at the same value of x as GMR, which is considered as a manifestation of correlation between NOMOKE and GMR.