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The magneto-optical (MO) imaging is one of the methods for visualizing the magnetization distribution corresponding to the leakage magnetic fields. In general, the MO imaging requires high-spatial resolution and high-contrast imaging. The spatial resolution of the MO imaging depends on the magnetic domain size. In this study, we used the polycrystalline garnet films with a domain size of about 50 nm for the high-resolution imaging. We also demonstrated MO imaging using the magnetophotonic crystal (MPC) with polycrystalline garnet films in order to improve the MO image contrast. The MO images of a carbon steel surface can be observed by means of the MPC. As a result, the high-spatial resolution and high-contrast MO image was obtained by MPC. [ABSTRACT FROM AUTHOR]

In this study, we investigated the magnetization response of the polycrystalline magnetic garnet film for stress. The calculation suggests that the balance of the magnetic anisotropic energy under magnetic field is an essential factor to modulate the magnetization by stress. We fabricated the magnetophotonic crystal based voltage driven type magneto-optic spatial light modulator, and measured the magneto-optic response for stress. The experimental results had a good agreement with our calculation. In our results, the magnitude and linearity of the modulation by stress was depending on static bias field, stress, and magnetostriction constant. The obtained results implied that the calculation could estimate the device performance by deciding material composition and prepare stress inside garnet. [ABSTRACT FROM AUTHOR]

We magneto-optically investigate the switching properties of the grooved pixels. The switching field of the 70%-grooved pixel achieves a factor of over two reductions more than that of the 100%-grooved pixel. The switching properties of the geometric pixel arrays for the magneto-optic spatial light modulators are very sensitive to the depth of the pixel groove, and also depend on the state of individual pixel, in additions to the state of the neighbors in two-dimensional pixel arrays. Optimally grooved pixels can allow high amounts of bismuth in the iron garnet film, and actually reduce the driving current of the magneto-optic spatial light modulator due to a low switching threshold field. [ABSTRACT FROM AUTHOR]

A magneto-optic spatial light modulator driven by an electric field is fabricated by using the electrostrictive effect of [Pb(Zr[SUB0.52]Ti[SUB0.48])O[SUB3]] (PZT) thin film. As the stress field induced by the PZT thin film reduces the anisotropy energy of the structured garnet film, we find that the pixels can be easily switched in accordance with or without the small external bias field. When peak-to-peak 8 V at the X and Y conductors is applied with the external bias field of 40 Oe at the fabricated device, the selected pixel is switched independently. [ABSTRACT FROM AUTHOR]

Effects of pixel groove depth and patterned permalloy assist film for the magnetization switching of LPE-garnet film were studied experimentally. The results showed that the magnetization field to switch a structured pixel could be reduced by controlling the pixel groove depth. It was also found that the permalloy assist film creates a unique pair-domain pattern within a single garnet pixel, which is useful for realizing a new type of magneto-optic spatial light modulator with high resistivity to noise. [ABSTRACT FROM AUTHOR]

We fabricated a one-dimensional magnetophotonic crystal (MPC), in which a magnetic layer of Co–ferrite (∼40 nm in thickness) is sandwiched by a couple of dielectric multilayer reflectors with (SiO[sub 2]/TiO[sub 2])×7 structure. The Co–ferrite layer was synthesized by ferrite plating from aqueous solution at 90 °C. The MPC is so designed to enhance magneto-optical Faraday rotation θ[sub F] at the Fabry–Pe´rot resonance wavelength λ of the multilayer structure. θ[sub F] was observed to increase by factor of ∼5.4, but at λ=∼620 nm which is deviated from the target resonance (λ=740 nm) and at very weak transmissivity. This may be because the Co–ferrite layer is rough in surface and smaller in thickness than the target thickness at which Fabry–Pe´rot resonance is designed to occur. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

We have developed three-dimensional magneto-optic spatial light modulators (3D-MOSLMs) that use magnetic domains as submicron scale pixels to represent holograms. Our display system uses a submicron-scale magnetic pixel array on an amorphous TbFe film to create a wide viewing angle hologram. However, in previous work the reconstructed images had a low intensity and a low optical contrast; brightness of the reconstructed image was 4.4×10-2cd/m² with 532 nm illumination light at 10.8 mW/cm², while display standard ISO13406 recommends 100 cd/m² or more. In this paper, we describe our development of a 3D-MOSLM composed of an artificial magnetic lattice structure of magnetophotonic crystals (MPCs). The MPCs enhance the diffraction efficiency of reconstructed 3D images and reduce the power consumption for controlling the magnetic pixels by a light localization effect. We demonstrate reconstructed 3D images using the MPC and show significant brightness improvement. [ABSTRACT FROM AUTHOR]

Current transport properties in Y1Ba2Cu3O7δ (YBCO) coated conductors obtained by pulsed laser deposition process on a CeO2 capped Gd2Zr2O7-IBAD template have been studied by spatially resolved measurements. We utilized low temperature scanning laser microscopy along with laser induced Seebeck effect imaging and scanning SQUID microscopy that allow us to visualize 1) distributed flux flow dissipation, 2) current blocking obstacles and 3) local current flow, respectively. Combination of those measurements leads deep insights into current limiting mechanism in the coated conductor. Our results show that non-uniform current flow due to spatially distributed obstacles is responsible for the dissipation, whereas grain connectivity in each YBCO grains is not the limiting factor. Typical period of those obstacles is several tens μm to hundreds μm. Detailed correlation between local current flow and dissipation has been observed. Present methods have great potential as tools for basic understanding of current limiting mechanisms in the coated conductors. [ABSTRACT FROM AUTHOR]

Abstract: In the present work we study the photonic band structure (PBS) and the polarization state of the Bloch eigenmodes of a two-dimensional magnetophotonic crystal (MPC) with square lattice formed from magneto-optically (MO) active cylinders. The refraction of light at the boundary of the MPC is analyzed. We found that both—the PBS and eigenmodes of the MPC—are most significantly altered by the MO activity in the vicinity of the degeneracies. For this case we demonstrated the possibility of an abrupt change in the propagation direction of light by the application of a magnetic field. For the Bloch wave vectors and frequencies corresponding to non-degenerate branches, the alteration of the PBS is shown to be negligible and eigenmodes almost completely coincide with linearly TE- and/or TM-polarized eigenmodes of the non-magnetic photonic crystal. [Copyright &y& Elsevier]

The polarization and angular dependences of the magnetorefractive effect (MRE) in metal–insulator nanocomposites in reflection and transmission geometries have been calculated in terms of the high-frequency, spin-dependent tunneling mechanism. The MRE exhibits a weak polarization and angular response at small angles of incidence. The MRE in reflection and transmission starts to grow strongly with increasing angle of incidence. The MRE in reflection in nanocomposites with metal contents corresponding to the insulating phase near the percolation threshold reaches the largest values with p-polarized light at an angle of incidence close to the Brewster angle. The results of the calculation are in a qualitative agreement with experimental data. © 2004 MAIK “Nauka / Interperiodica”. [ABSTRACT FROM AUTHOR]

Abstract-The magnetorefractive effect in ferromagnetic metal-insulator granular nanostructures (CoFeZr)-SiO[SUBn], Co-Al-O, FeSiO[SUBn], and (CoFe)-(Mg-F) is investigated in the infrared spectral region in a wavelength range from 5 to 20 μm. The magnitude of the effect varies from 0.1 to 1.5% for different nanocomposites and strongly depends on the frequency of light and magnetoresistance. It is shown that the reflection coefficient changes in a magnetic field not only due to the magnetorefractive effect, but also due to the even magnetooptical effect. Simple relations describing this effect are given for the case when the reflection from the substrate is insignificant and in the case of a three-layer (insulator-film-substrate) system. The expression for the frequency dependence of the magnetorefractive effect in nanocomposites is derived and its features in the case of high-frequency spin-dependent tunneling are analyzed. [ABSTRACT FROM AUTHOR]

We prepared the reflection type magnetophotonic crystals (R-MPC) to enhance the magneto-optic property of magneto-optic spatial light phase modulator (MOSLM). Magnetophotonic crystals have a localized wavelength by using a defect layer in which the magneto-optic property can be increased tremendously. By the calculation, it was revealed clearly that Kerr rotation can be enhanced with increasing the repetition number (k) which is the number of dielectric layer. In this study, Dy1.0Bi1.5Y1.0Fe3.8Al1.2O12(DyBi:YIG) garnet material, of which Faraday rotation angle is about -3 deg/μm, was utilized as a defect layer. At the designed wavelength of 532 nm and k=5, SGGG/ [SiO2 /Ta2O5]2 /DyBi:YIG/ [SiO2 /Ta2O5]k structure fabricated with garnet thickness of 347.6 nm showed Kerr rotation angle of 26° and reflectivity of 0.2% which is coincident considerably with the results (θk=30° and R=0.59%) calculated by the matrix approach method. The fabricated R-MPC-MOSLM structure exhibited the magneto-optic property of about 25 times higher than single garnet film in consideration of the thickness of magneto-optic material. [ABSTRACT FROM AUTHOR]

Discusses the analysis of Magneto-optical Faraday effect of discrete magnetic media by employing a model with a one-dimensional quasirandom array structure. Modelling and theory of Discrete magnetic media; Results and discussion; Conclusions.

Resonant transversal magneto-optical Kerr effect (TKE) is experimentally studied in 2D nickel magnetoplasmonic crystal. Gradual transition between collinear and bi-directional types of surface plasmon-polariton phase matching and its influence on TKE resonances are observed by measuring and analyzing dependence of reflectance and TKE spectra on the azimuthal angle. [ABSTRACT FROM AUTHOR]

Properties of three-dimensional magneto-photonic crystals based on artificial opals were studied by optical spectroscopy. We have investigated an influence of magnetic materials embedded into opal lattice on optical and magnetic properties of synthesized composites. It was shown that increase of volume fraction of magnetic material in opal lattice leads to decrease of transmissivity of synthesized composites. We measured Faraday rotation of opal-magnetite composites and found considerable changes in the Faraday rotation inside the (111) photonic bandgap. [ABSTRACT FROM AUTHOR]

Abstract: It was founded using the magneto-optical technique that the domain wall in the iron-based amorphous ferromagnet in its movement experienced enhanced deceleration on the surface compared to the volume. The surface deceleration of the wall intensifies under water molecules adsorption on the sample surface. This effect is explained by the domain wall interaction with magnetic micro-defects observed on the sample surface using a magnetic force microscope. [Copyright &y& Elsevier]

Abstract: The necessary conditions for the observation of the Faraday effect in 2D magneto-photonic crystals are discussed. It is found. that the Faraday effect may be observed in the directions where any couple of the wave vectors of the harmonics consisting the Bloch waves of TE and TM solutions in zero magnetic field are identical. This direction corresponds neither to Faraday nor to Voigt geometry. [Copyright &y& Elsevier]

The magnetic, optical, and magnetooptical properties of granular (FePt)1 – x(SiO2)x nanocomposites in the disordered state and after heat treatment were studied. The magnetooptical response of samples in which the concentration of the metallic component approached the percolation threshold was observed to become considerably enhanced. Modeling transverse Kerr effect (TKE) spectra in a straightforward effective medium approximation provided a qualitative fit to the experimental data over a broad concentration range. The dependences of the Kerr effect on the SiO2 concentration in the nanocomposite are not monotonic and exhibit a sharp break near the percolation threshold. An analysis of the field dependences of the TKE and magnetization curves revealed that structural changes associated with ordering in annealed FePt films occur only in nanocomposites with fairly large grains. © 2005 Pleiades Publishing, Inc. [ABSTRACT FROM AUTHOR]

The fabrication of magnetophotonic crystals (MPC) composed from Bi-substituted yttrium-iron-garnet films separated by silicon oxide layers is presented. The enhancements of the Faraday rotation, second-harmonic generation and nonlinear magneto-optical Kerr effect are observed at the photonic band gap edge. These demonstrate strong light-matter magnetic coupling in MPC and provide the prospects of the new magneto-optical materials for applications. [Copyright &y& Elsevier]

Abstract: Magneto-optical Kerr effect enhancement in longitudinal and transversal configurations is systematically studied in one- and two-dimensional magnetoplasmonic crystals based on the nanostructured nickel films. Spectral dependences of magneto-optical effects demonstrate resonant features with the Fano-type lineshape in the spectral vicinity of the Wood''s anomaly associated with excitation of surface magnetoplasmons in Voigt and Faraday configurations, respectively. [Copyright &y& Elsevier]

Abstract: We have demonstrated a magneto-optical spatial light modulator in which functionality is realized by (i) heating up to Curie temperature (T c) magneto-optical elements (pixels) with a semiconductor laser and (ii) application of a switching magnetic field. The pixels were made of films of amorphous rare earth–transition metal compounds (TbFe films with T c=403K and DyFe films with T c=343K) having good magneto-optical responses for wavelengths from the visible spectral range. We have found that the magnetization direction of pixels can be modulated with a laser radiation density of 5mJ/cm2 and in a switching magnetic field of 15Oe. [Copyright &y& Elsevier]

The field distribution of a light wave near a magnetic defect in a one-dimensional photonic crystal is analyzed. It is shown that, by properly varying the magnetic defect thickness or the parameters of the photonic crystal surrounding the defect, one can create a situation where the electric field of a light wave will be localized predominantly inside the magnetic layer or, conversely, in the immediate vicinity of the layer surface. This opens up possibilities for optimizing the Q factor of a magnetic microcavity in the presence of dissipation in the magnetic layer and, hence, for enhancing the linear and nonlinear magneto-optical effects. The possibility of separating the contributions from the surface and volume of the magnetic material to the nonlinear magnetooptical properties by properly varying the field distribution over the defect thickness is discussed. [ABSTRACT FROM AUTHOR]