Magneto-optical effects calculated for granular composites with magnetized nano-onions dispersed in matrixes

For granular composite having nano-onions (nanosized, multicore-shell structured particles) dispersed in a matrix we derived an effective dielectric permittivity tensor including off-diagonal terms, based on the Maxwell Garnett effective field approximation. The magneto-optical Kerr effect was calculated from the effective permittivity tensor for the composite containing nano-onions with Au (core)/Fe (inner shell)/Au (outer shell) structure. The off-diagonal term, <epsilon(xy)>=<epsilon(xy)'>+i<epsilon(xy)">, of the effective permittivity tensor and Kerr effect derived from it exhibit a dispersion relation, <epsilon(xy)'> making a peak and <epsilon(xy)"> crossing zero, at a wavelength around 630 nm. The dispersion may be ascribed to the plasma resonance of Au, because similar peak was found in the Kerr rotation spectra for compositionally modulated multilayered Au/Fe films due to the plasma resonance of Au. (C) 2002 American Institute of Physics.