Enhancement of optical and magneto-optical effects in three-dimensional opal/Fe3O4 magnetic photonic crystals

Abstract

Three-dimensional magnetic photonic crystals, based on an artificial opal matrix with embedded magnetite Fe3O4, were investigated in both transmission and reflection in the near-infrared and visible spectral range. A strong enhancement of the polar Kerr effect and a modification of the Faraday effect have been found near the photonic band gap at about 1.8 eV. Surprisingly the shapes of the loops of magnetic hysteresis measured by magnetic circular dichroism were found to depend on the wavelength of light. This observation has been explained using a model where two types of magnetite particles have different coercive fields.