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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. [ABSTRACT FROM AUTHOR]

Three-dimensional magnetophotonic crystals (MPCs) based on artificial opals infiltrated by yttrium iron garnet (YIG) are fabricated and their structural, optical, and nonlinear optical properties are studied. The formation of the crystalline YIG inside the opal matrix is checked by x-ray analysis. Two templates are used for the infiltration by YIG: bare opals and those covered by a thin platinum film. Optical second-harmonic generation (SHG) technique is used to study the magnetization-induced nonlinear-optical properties of the composed MPCs. A high nonlinear magneto-optical Kerr effect in the SHG intensity is observed at the edge of the photonic band gap of the MPCs. [ABSTRACT FROM AUTHOR]

A correction to the article "Enhancement of optical and magneto-optical effects in three-dimensional opal/Fe3O4 magnetic photonic crystals" that was published in the October 14, 2008 issue is presented.

Scanning tunneling microscopy and scanning tunneling spectroscopy (STS) are used to investigate the local electronic behavior of Pt-Si nanostructures fabricated in an opal matrix formed by silica spheres of 250 nm diameter. Si and Pt are regularly distributed inside the opal pores and form nanoscale metal-semiconductor-metal junctions. Normalized differential conductance curves enable us to study the distribution of Pt and Si and to detect the presence of regions showing a surface band gap in the range 0.5-0.8 eV, possibly associated with the formation of silicides. STS appears as a suitable technique for the electrical characterization of opal-based nanostructures. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]