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We present experimental and theoretical results of the molecular sensing performance of a novel platform based on magnetic modulation of surface-enhanced infrared absorption spectroscopy. For this, we study the effect that molecular infrared vibrations of a PMMA layer have on the optical and magneto-refractive response of spintronic antennas. Specifically, a periodic array of rods is fabricated from giant-magneto-resistance Au/Ni81Fe19 metallic multilayers, and the effect of depositing a layer of PMMA on top of the array is investigated from both experimental and theoretical points of view. We find that the relative changes induced by the infrared vibrations of PMMA on the magneto-refractive signal are larger than the relative changes induced on the optical transmission. This result indicates that the magneto-refractive response is more sensitive to the excitation of molecular vibrations than the optical response and fosters the development of a novel type of an infrared sensing technique based on spintronic antennas: Magneto-Refractive Surface-Enhanced Infrared Absorption (SEIRA) Spectroscopy. [ABSTRACT FROM AUTHOR]

The structure, morphology, composition, magnetism, and magneto-optical (MO) response of FePd films sputter deposited at different temperatures on a monocrystalline V(001) buffer layer is studied. It is observed that the perpendicular magnetic anisotropy (PMA) could be ascribed to the V interdiffusion and the formation of a FeV alloy, being the global sample saturation magnetization also reduced.

Research describing the effects of nitrogen incorporation in iron based thin films is presented. The structure and magnetic properties of the iron lattice are investigated for films grown at different temperatures.

Multilayered (ML) structures having alternating nonmagnetic and magneto-optically active layers are important in magneto-optical (MO) recording. In such systems the magneto-optical Kerr effect (MOKE) can be enhanced. The potential to modify the magneto-optical properties of polycrystalline Co films by postdeposition annealing in air or oxygen, is discussed. The result is a well-defined transparent, bilayered fcc Co(sub3)O(sub4) structure, on metallic Co.

A study that seeks to determine factors that influence the magnetic and magneto-optical attributes of sputtered epitaxial FePd (001)alloy films is developed. An ultrahigh vacuum triode-sputtering system is used for the study. Results indicate the strong influence of deposition temperature on the degree of chemical ordering. Changes in the Kerr effect spectra and magnetic anisotropies are also observed.

Analysis of the optical properties of GaAs AlAs superlattices grown on (113)A-oriented GaAs substrates by molecular beam epitaxy (MBE) and atomic layer MBE (ALMBE) reveals that MBE superlattices have rougher interfaces, but lesser nonradiative recombination centers than ALMBE lattices. MBE superlattices have a corrugation that does not exhibit periodicity. The photoluminescence excitation spectra of ALMBE superlattices only reveal phonon-associated replicas.

We report a study of Au:CoNPs and Co:AuNPs doped magnetoplasmonic systems. In particular, we analyze the effect of adding different concentrations of Co (or Au) nanoparticles (NPs) in a Au (or Co) matrix on both the optical and magneto-optical constants. Through the use of a simple effective medium model, relevant changes in the optical properties of the Au NPs compared to those of bulk material have been identified. Such effects are not observed in the Co NPs system. However, in both systems, there is an increase of the effective diameter of the NPs as compared to the real diameter that can be due to interface effects surrounding the NPs. Moreover, the magneto-optical constants values of both systems are smaller (in absolute values) than expected, which could also be attributed to interface effects such as hybridization between Au and Co. [ABSTRACT FROM AUTHOR]

We have analysed the effect that holes have on the properties of propagative surface plasmon modes in semitransparent nanoperforated Au films. The modes have been excited in Kretschmann configuration. Contrary to continuous films, where only one mode is excited, two modes are observed in Au nanohole array. The origin of this different behavior is discussed using effective optical properties for the nanoperforated films. The presence of the holes affects the effective optical constants of the membranes in two ways: it changes the contribution of the free electrons, and it gives rise to a localized transition due to a hole induced plasmon resonance. This localized transition interacts with the propagative surface plasmon modes, originating the two detected modes. [ABSTRACT FROM AUTHOR]

In this paper, we analyze the magnetoplasmonic (MP) features and sensing capabilities of Au/Fe/Au trilayer structures, as transducers of the magneto-optic surface plasmon resonance (MOSPR) biosensor. This biosensor, which can surpass the sensitivity of the standard SPR sensor, is based on a MP modulation technique generated by the simultaneous stimulation of the surface plasmon polaritons (SPP) and the transversal magneto-optical Kerr effect (TMOKE). We study the magneto-optical activity of the trilayers as a function of the thickness and position of the Fe layer. We first demonstrate that this kind of structure allows modulating the SPP through an external magnetic field and moreover, induce a strong enhancement of the TMOKE effect. The modulation of the SPP is linearly proportional to the thickness of Fe layer and inversely proportional to the distance between the Fe layer and the external dielectric medium. Finally, we experimentally confirm a twofold increase in the MOSPR sensitivity with respect to the intensity-interrogated SPR biosensor in bulk refractive-index changes, keeping a similar chemical resistance and stability, unprecedented in other MP transducers, and biofunctionalization protocols. [ABSTRACT FROM AUTHOR]

We present a study of the optical and magneto-optical (MO) properties of Co nanoparticles embedded in ZrO2 in the spectral range from 1.4 to 4.3 eV. The nanostructured films were prepared by pulsed laser deposition in a wide range of Co nanoparticle concentrations varying from 20% to 80%. For Co concentration lower than x∼0.45 the size of the nanoparticles was found to remain almost constant (D∼2.5 nm), whereas it increases above it. Differences are found between the optical and MO constant of the Co nanoparticles and those of continuous Co films. Those differences are associated with size effects of the intraband contribution inside the nanoparticles. [ABSTRACT FROM AUTHOR]

We present a study on the magnetic anisotropy and magnetization reversal of Fe(110) islands grown on Al2O3 versus the island size, the island size distribution, and the magnetic interaction between islands. For small islands magnetically connected via a polarizable capping layer, the samples behave as a uniform film with an induced uniaxial in-plane anisotropy. Magnetically isotropic samples are obtained when the islands size is increased. Transverse susceptibility measurements show that the magnetic anisotropy of the particles is macroscopically averaged due to the interisland magnetic interaction. The island size distribution is correlated to the magnetic anisotropy field dispersion. When the capping layer material is Al, a superparamagnetic behavior is found due to the absence of the interisland interaction. [ABSTRACT FROM AUTHOR]

We present a structural, morphological, magnetic, and magneto-optical study of cobalt nanoparticles deposited on 50 Å AlN/c-sapphire substrates and embedded in an AlN matrix. The dependence of the properties of Co nanoclusters deposited on AlN with growth temperature and amount of deposited Co are studied and discussed. Also we directly compare the properties of as grown and AlN embedded Co nanoclusters and show that the AlN matrix has a strong impact on their magnetic and magneto-optical properties. [ABSTRACT FROM AUTHOR]

Magneto-optic (MO) studies are performed on regular arrays of Fe(100) micrometric squares, where the elements are patterned with different sizes (2.5–10 μm) and separations (0.2–0.6 μm). When a laser beam is focused inside the patterned structure a Bragg diffraction pattern is produced allowing MO studies on both reflected and diffracted spots. The magnetic anisotropy has been analyzed by in-plane MO hysteresis loops finding that, for square sizes below 2.5 μm, it is not consistent with the Fe crystalline cubic anisotropy, presenting a uniaxial-like behavior. The magnitude of the corresponding anisotropy constants has been determined by analyzing the array response (on reflected and diffracted spots) to a rotational magnetic field in a magneto-optical torque setup. For square sizes of 10 μm the anisotropy induced by patterning is negligible whereas for the small squares (2.5 μm) the uniaxial magnetic constant has been found to be roughly 0.2 times the Fe cubic anisotropy constant. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Changes in electronic transition energies at different strain levels yield shear and hydrostatic potentials of GaAsP layers. Electroreflectance of the layers indicates the energy points in the band-gap electronic transition along the transition-plane of the layers. The energy spectrum is recorded with the light polarized parallel to the (100) direction to eliminate the linear electro-optical component.

The optical and magneto-optical (MO) properties of Co nanoparticles embedded in ZrO2 in the spectral range from 1.4 to 4.3 eV are studied. For Co concentration lower than x~0.45 the size of the nanoparticles is found to remain almost constant, whereas it increases above it.

Determines the optical direct interband transitions in a set of AlInAs and AlGaP alloys by using spectroscopic ellipsometry. Factor that made it possible to obtain a wide class of new materials with optical properties different from those of the binary compounds; Advantage of using the ellipsometric method; Function of the aluminum composition.

Investigates optical properties of strained-layer superlattices. Reasons for interests in semiconductor heterostructures made of lattice-mismatched materials; Details on the experiment; Calculation of the optical properties of structures consisting of two superlattices confining gallium arsenide quantum well.

Presents a study that investigated the optical properties of gallium arsenide/aluminum arsenide superlattices grown by molecular beam epitaxy (MBE) and atomic layer MBE on gallium arsenide substrates. Photoluminescence excitation spectra of atomic layer MBE superlattices; Comparison between the interfaces of MBE and atomic layer MBE; Factor to which the differences in the optical properties of the samples can be attributed.

Presents a study that investigated the optical properties of aluminum-gallium phosphide semiconductor alloys using electrolyte electroreflectance. Relationship between transition energies and alloy composition; Determination of the flatband potential of the alloys; Analysis of the indirect energy gap of the samples.

We present a study of the optical and magneto-optical (MO) properties of Co nanoparticles embedded in ZrO2 in the spectral range from 1.4 to 4.3 eV. The nanostructured films were prepared by pulsed laser deposition in a wide range of Co nanoparticle concentrations varying from 20% to 80%. For Co concentration lower than x∼0.45 the size of the nanoparticles was found to remain almost constant (D∼2.5 nm), whereas it increases above it. Differences are found between the optical and MO constant of the Co nanoparticles and those of continuous Co films. Those differences are associated with size effects of the intraband contribution inside the nanoparticles. [ABSTRACT FROM AUTHOR]