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Laser ablated zinc ferrite (ZnFe 2 O 4 ) films deposited at O 2 pressure of 0.16 mbar onto fused quartz substrates are nanocrystalline and display net magnetic moment dependent on the substrate temperature (T s ) during deposition. At T s = 350 °C, the room 4πM s reached the maximum of 3 kG. The films were studied by spectral ellipsometry and magnetooptical (MO) Kerr effect spectroscopy at photon energies between 1 and 5 eV at room temperature in the longitudinal magnetic flux density 1.14 T. The optical and MO spectra show structural details typical for inverted spinels. Our ZnFe 2 O 4 samples display amplitudes somewhat reduced with respect to those in other ferrimagnetic oxides with the exchange coupled Fe3+ pairs, i.e., in Li 0.5 Fe 2.5 O 4 and MgFe 2 O 4 spinel ferrite and magnetoplumbite, PbFe 12 O 19 . The lower amplitudes are probably due to the interplay of nanocrystalline nature and lower degree of spinel inversion in the ZnFe 2 O 4 laser ablated films.

In order to optimize a 1.3 μm integrated optical isolator using a CoFe alloy for the non-reciprocal magneto-optical (MO) transverse Kerr effect, we have measured the optical and magneto-optical indices of Co90Fe10 and Co50Fe50 alloys grown in the Al2O3/Al/CoFe/GaAs multilayer structure. The optical reflectivity and MO rotation and ellipticity measurements were performed at variable incidence angle and s and p polarization of the incident light. In order to determine the optical and MO indices, the experimental data were fitted using a Matlab implementation of a standard multilayer Yeh formalism including multiple reflections. This original procedure allows precise determination of the optical and MO indices of CoFe alloys.

Methodology and selected applications of magneto-optical (MO) spectroscopic scatterometry (MOSS) are presented on various types of magnetic gratings made by lithographic patterning. Three types of theoretical models with different levels of accuracy are described in detail: a rigorous one, an analytical approximation, and a model mostly appropriate for real structures affected by line-edge roughness (LER). The MOSS approach, based on explaining diffracted MO Kerr effect measurements by simulations employing the mentioned models, is demonstrated as a technique highly sensitive to nanoscale features such as native oxide overlayers, as well as capable of determining the LER characteristic quantitatively. Further possibilities to study unsaturated magnetic structures and compositions of magnetic materials including imperfect deposition or aging processes are suggested.

Spectroscopic ellipsometry (SE) is used to study a sinusoidal-relief grating fabricated on a surface of transparent polymer. An optically thick polymer layer is situated on a glass substrate and its refraction index is optically matched to the index of the glass. The rigorous coupled-wave analysis, implemented as the airy-like internal reflection series, is applied to calculate the optical response of the relief grating. The entire optical response of the sample is determined by employing incoherent backreflections at the interface between the polymer and the glass. The parameters describing the dimensions and the real shape of the sine-like relief, as well as the quality of the optical matching between the polymer and the glass, are determined using SE together with atomic force microscopy as a complementary technique.

Deep lamellar diffraction gratings fabricated by etching a transparent quartz plate are studied using spectroscopic ellipsometry. The rigorous coupled-wave analysis is used to calculate the optical response of the gratings. Three parameters of the rectangular profile are determined by utilizing the least-square method. Detailed investigation of the spectral dependences demonstrates the uniqueness of the solution. Observing the spectral dependences of Wood anomalies suggests that even complicated profiles can be fitted with high authenticity.

Spectroscopic ellipsometry, reflectometry and magnetooptical (MO) spectroscopy in the zero and first diffraction orders are used to analyze submicron ultrathin MO gratings. Two different theoretical approaches, a rigorous analysis and an approximate method, are used to simulate the optical and MO response of the gratings. The numerical analysis suggests the presence of native oxide layers on the substrate and capping. A strong spectral anomaly observed in the MO response is identified by the integration of both theoretical approaches. The possibility to monitor the quality and topography of shallow gratings with high sensitivity is concluded.

Pulse laser deposited La2/3Sr1/3MnO3 ultrathin films on SrTiO3 substrates were characterized by polar and longitudinal Kerr magneto-optical spectroscopy. Experimental data were confronted with theoretical simulations based on the transfer matrix formalism. An excellent agreement was achieved for a 10.7 nm thick film, while a distinction in the Kerr effect amplitudes was obtained for a 5 nm thick film. This demonstrated the suppression of ferromagnetism due to the layer/substrate interface effects. A revised, depth-sensitive theoretical model with monolayer resolution described the experimental data well, and provided clear cross-section information about the evolution of ferromagnetism inside the film. It was found that the full restoration of the double-exchange mechanism, responsible for the ferromagnetic ordering in La2/3Sr1/3MnO3, occurs within the first nine monolayers of the film. Moreover, all the studied films exhibited magneto-optical properties similar to bulk crystals and thick films. This confirmed a fully developed perovskite structure down to 5 nm.

Magnetite Fe3O4 films were grown on single crystal MgO (001) substrates using facing target sputtering technique. Conversion Electron Mossbauer Spectroscopy and magneto optical polar Kerr spectra have confirmed the stoichiometric repartition of Fe cations corresponding to the inverse spinel structure and the electronic structure characteristic of bulk Fe3O4. Hysteresis loops carried out at room temperature show that, in a 1 T applied magnetic field, only 60% of the saturation magnetization is detected. This behavior is discussed in correlation to the antiphase boundaries (APBs) observed by electron microscopy. Magnetic force microscopy studies show that magnetic domains are larger than the mean distance between APBs.

Measurements and analysis of spectroscopic reflection ellipsometry and magneto-optical polar and longitudinal complex Kerr effect are reported on a natural (111) fece of a high quality NiFe2O4 single-crystal. The experimental reflection data is expressed in terms of the permittivity tensor. This information is employed in modeling experimental polar Kerr spectra of a NiFe2O4 film and a satisfactory agreement has been achieved. These results demonstrate the importance of the spectroscope magneto-optic reflection ellipsometry in the diagnostics of magnetic oxide films with thicknesses in the range 101 to 102 nm.

We describe our magnetic and magneto-optic (MO) studies on some multilayers based on Ag, Au and Pt, such as Fe/Ag, Fe/Pt, CoNi/M (M = Pt, Au) prepared by evaporation under UHV conditions. In CoNi/M, the surface anisotropy increases linearly with the addition of Co verifying the single ion model. The Curie temperature can be tailored by the addition of Co without affecting adversely the properties of interest for MO storage applications. For instance, in Fe/Ag, the MO effect shows enhancement due to Ag plasma resonance and in Fe/Pt the effect is due to interaction of Pt. The spectra can be explained by a phenomenological model though quantitative agreement is not obtained. In Au-based multilayers, the MO Kerr spectra show the effect of plasma resonance of Au, particularly for thinner layers. Some of the results could be modelled by electromagnetic model. The Kerr spectra for CoNi alloy films could also be modelled with success using effective medium theory which also confirms the absence of any effect from hybridisation between Co and Ni a result which supports our conclusions on the surface anisotropy.

Polar magnetooptics (MO) is able to probe the magnetization depth profile in ultrathin magnetic film structures on a nanometer scale. This information can be deduced by modelling the MO effects in the considered layered medium when performing MO experiments with a compensator or changing the wavelength of the incident light beam. Spectroscopic MO measurements are then helpful for analysing this phenomenon in detail. The in-depth selectivity of MO effects for magnetization is demonstrated for a simple ultrathin film structure consisting of two magnetic Co layers with perpendicular anisotropy separated by a non-magnetic Au spacer layer. The individual magnetic contributions of the two Co layers may be observed directly when performing MO Kerr measurements at selected compensator phase shifts or photon energies. The experimental data are interpreted by MO calculations in both cases.

This work is devoted to the systematic study of the optical and magneto-optical properties of sputter deposited CuFe₂O₄ thin films in the photon energy region between 2 and 5 eV using spectroscopic ellipsometry and magneto-optical Kerr spectroscopy. The spectral dependence of both the diagonal and off-diagonal elements of the permittivity tensor is determined. A complete picture about the electron transitions in CuFe₂O₄ is suggested in the frame of intervalence charge transfer and intersublattice charge transfer transitions. The effect of deposition conditions and post-deposition treatment in CuFe₂O₄ films upon the optical and magneto-optical properties is discussed.

The properties of nanometer-thick yttrium iron garnet (YIG) films are strongly influenced by interfaces. This work employs spectral ellipsometry (SE) and magneto-optic polar Kerr rotation (PKR) to characterize YIG films with thickness, t, from 6 nm to 30 nm grown on Gd3Ga5O12 (GGG) substrates oriented parallel to (111) plane. The films display a surface roughness of 0.35 nm or lower. The analysis of the SE data at the photon energies of 1 eV

Complex polar Kerr and Faraday effects between 1.5 and 5.2 eV in ultrathin Au/M/Co/Au films, with M = Au, Ag or Cu, prepared by thermal evaporation under ultra high vacuum condition are reported. The structure in the dispersion spectra is dominated by the effect of the Au layer underneath the ultrathin Co film. Thanks to the high layer perfection and step-like interface profiles strong sharp peaks in Kerr rotation, centered at the Au plasma edge near 2.5 eV, are observed. The introduction of Ag or Cu overlayers, which also display plasma edge effects in the considered energy range, modifies the spectra. This behaviour is satisfactorily explained by the electromagnetic wave model in magnetic multilayers.

Sputtered Co/Cu multilayers were studied by means of magneto-optical (MO) Kerr spectroscopy. Remarkable changes in the MO spectra were observed for the multilayers where antiferromagnetic coupling take place. This may indicate the changes in the electronic properties of Cu layers. The optical nature of this MO behaviour was verified by ellipsometric measurements.

This paper deals with the study of magneto-optical effects exhibited in perfect Au/Co/Au ultrathin films structures as a function of magnetic field and photon energy. They stand as ideal basic structures to test theories describing the magneto-optical effects in multilayers. In both optical transmission and polar Kerr rotation dispersion spectra, the main feature is a prominent peak centered near the photon energy of 2.5 eV, which corresponds to the plasma edge and reflectivity minimum in gold. The observed trends in magneto-optical effects are explained using the electromagnetic wave theory starting from the published optical and magneto-optical constants values in gold and cobalt thick films. The polar Kerr effect in our samples is a sum of one independent plus one linearly dependent term on the Co film thickness. The nonzero value of the thickness-independent term indicates the presence of a contribution not accounted for by the employed electromagnetic wave model.

Complex polar Kerr effect spectra in rf-sputtered Fe/Ag multilayers were measured in the spectral range 1.5–53 eV in a magnetic field of 0.45 T. The thicknesses of the individual iron layers in the three samples investigated were 11, 3.6 and 0.6 mm, while that of silver was kept at 6 nm. The observed spectra are explained in terms of the electromagnetic interaction in planar magnetic multilayer systems using published optical constants of iron and silver.

A new null ellipsometer is described that uses photoelastic modulator (PEM). The phase modulation adds a good signal-to-noise ratio, high sensitivity, and linearity near null positions to the traditional high-precision nulling system. The ellipsometric angles Delta and psi are obtained by azimuth measurement of the analyzer and the polarizer-PEM system, for which the first and second harmonics of modulator frequency cross the zeros. We show that the null system is insensitive to ellipsometer misadjustment and component imperfections and modulator calibration is not needed. In addition, a fast ellipsometer mode for fine changes measurement of ellipsometric angles is proposed.

The rigorous coupled wave theory dealing with optics of discontinuous two-dimensional (2D) periodic structures is reformulated by using the complex Fourier factorization method, which is a generalized implementation of the fast Fourier factorization rules. The modified approach yields considerably improved convergence properties, as shown on three samples of 2D gratings made as periodically arranged cylindrical holes on the top of quartz, silicon, and gold substrates. The method can also be applied to the calculation of 2D photonic band-gap structures or nonperiodic cylindrical devices, and can be generalized to elements with arbitrary cross-sections.

Nanometer (nm)-thick yttrium iron garnet (Y3Fe5O12, YIG) films present interest for spintronics. This work employs spectral ellipsometry and magneto-optic Kerr effect (MOKE) spectra to characterize nm-thick YIG films grown on single-crystal Gd3Ga5O12 substrates by magnetron sputtering. The thickness (t) of the films ranges between 10 nm and 40 nm. Independent on t, the polar MOKE hysteresis loops saturate in the field of about 1.8 kOe, consistent with the saturation magnetization in bulk YIG (4πMs ≈ 1.75 kG). The MOKE spectrum measured at photon energies between 1.3 eV and 4.5 eV on the 38-nm-thick film agrees with that measured on single-crystal YIG bulk materials. The MOKE spectrum of the 12-nm-thick film still preserves the structure of the bulk YIG but its amplitude at lower photon energies is modified due to the fact that the radiation penetration depth exceeds 20 nm. The t dependence of the MOKE amplitude is consistent with MOKE calculations. The results indicate that the films are stoichiometric, s...

Magneto-optical (MO) spectroscopy combined with spectroscopic ellipsometry has been used to learn about the electronic transitions in La2∕3Sr1∕3MnO3 (LSMO) film pulse laser deposited onto SrTiO3 (100) substrates. The dispersion function of LSMO films was parametrized by the sum of three damped Lorentz oscillators and adjusted together with the film thickness numerically. With the knowledge of film optical properties the off-diagonal elements of the LSMO permittivity tensor (magneto-optical constants) were calculated from the complex polar Kerr effect measured on the thickest (60nm) LSMO film (considered as optically thick). The considered approximation as well as the reliability of the obtained optical and MO constants was verified by the consistence of the calculated and experimental MO spectra for the thinner LSMO films (where the propagation effect plays an important role). The resolved electronic transition centered at about 4eV features the spectral dependences of diagonal and off-diagonal elements o...

An ellipsometric configuration for measurement of the complex transverse magneto-optical Kerr effect is described that uses a photoelastic modulator (PEM). The real and imaginary parts of the complex transverse Kerr effect are represented as small perturbations of ellipsometric angles psi and Delta. The measurement, based on null ellipsometry and zone averaging, gives high signal typical for modulation techniques and insensitivity to other magnetisation components and system imperfections. The method is demonstrated by the measurement of transverse component during magnetisation reversal in a thin cobalt film. Web of Science 1 art. no. 06017

Spectroscopic ellipsometry (SE) with microscopic measurement spot is applied to extract geometrical parameters of a bi-periodic array of holes patterned on the top of an Si wafer, namely the holes' diameter and depth, while the period of the patterning is assumed same as the value intended by the manufacturer. The SE response of the structure is simulated by the rigorous coupled-wave analysis implemented as the Airy-like internal reflection series, whose detailed description for the case of 2D gratings is provided with a brief demonstration of its convergence properties. The result of the extraction by SE is compared with results obtained by scanning electron microscopy (SEM) with reasonable agreement. The difference between some of the SE, SEM, and nominal parameters are discussed and the possibility to increase the accuracy of SE-based metrology is suggested.

The rigorous coupled wave analysis (RCWA) implemented as the Airy-like internal reflection series (AIRS) is applied in a theoretical analysis of the optical response of diffraction gratings. Detailed theoretical description of the RCWA with respect to the AIRS implementation is provided, including the application of Li's Fourier factorization rules and the recursive algorithm for sliced relief gratings. Numerical analysis of convergence properties including computation time is demonstrated for structures made of transparent, semiconductor, or metallic materials.

A new null ellipsometer has been recently proposed that uses photoelastic modulator (PEM). The phase modulation adds a good signal-to-noise ratio, high sensitivity, and linearity near null positions to the traditional high-precision nulling system. The ellipsometric angles Delta and psi are obtained by azimuth measurement of the analyzer and the polarizer--PEM system, for which the first and second harmonics of modulator frequency cross the zeros. In this paper we discuss influence of component imperfection on precision of null measurement. Particular interest is devoted to azimuth angle error of compensator and modulator. Effect of residual birefringence of PEM is discussed. We show that the null system is insensitive to ellipsometer misadjustment and component imperfections and modulator calibration is not needed.

Spectroscopic ellipsometry (SE) and magneto-optical (MO) spectroscopy are applied to analyze three sets of shallow magnetic gratings. The experimental data of SE are used to extract geometrical parameters of several samples. A half-micrometer thick transparent interlayer present between the periodic magnetic wires and the substrate in one of the sets of the samples is used to increase the sensitivity of SE and MO measurements. Thanks to this sensitivity the geometrical parameters can be extracted together with the material composition of the magnetic film. In order to interpret the magneto-optical Kerr effect (MOKE) measurement, three theoretical approaches are used in the simulations, the rigorous coupled-wave method (CWM), the local mode method (LMM), and a new approach based on comparing CWM with LMM with defining a 'quality factor' of the grating with respect to the wire edges. Using the MOKE spectra in the 0th and -1st diffraction orders, one set of the samples made with a protection capping is analyzed with respect to the native-oxidation process. The quality factor of these samples is extracted from MOKE in the -1st diffraction order for p-polarized incidence. The monitoring system based on both SE and MOKE is rated as highly sensitive and precise, and with accurate determination of the optical and magneto-optical constants it could by applied in multi-parameter fitting.

We report on the strain effects upon the magneto-optical properties of La 2/3 Sr 1/3 MnO 3 thin films, which were grown using the pulsed laser deposition technique under low ozone pressure. Two notable features can be observed in the experimental longitudinal and polar magneto-optical spectra at ∼2 and ∼3.4 eV: the first, not affected by the strain effects, is assigned to the (t 2g →e g ) majority-spin intra-band transition, whereas the second corresponds to the (O (2p) → t 2g ) charge transfer transition between minority-spin bands.

This work is devoted to the study of the effect of deposition conditions and post-deposition treatment in Cu-ferrite films using magneto-optic Kerr effect at both polar and longitudinal configurations between 2 and 5 eV. In the sample annealed at 850 degrees C the amplitudes are comparable with those observed in bulk ferrite crystals whereas as-deposited films showed reduced amplitudes and smeared out structure. (C) 2004

The authors discuss magnetooptical spectroscopic studies of Pt/Ni and Pd/Ni multilayers. The films were grown onto glass (Pt/Ni) and mica (Pd/Ni) substrates by dual electron beam evaporation. In the Pt/Ni set the thickness of Pt layers was kept constant at 2 nm while that of Ni layers was 1.2 and 2.9 nm. For the Pd/Ni set the individual Ni and Pd layer thicknesses varied between one and ten monoatomic layers. Simultaneous polar and longitudinal magnetooptical Kerr rotation and ellipticity experiments were carried out in the spectral range between 1.5 and 5.2 eV. The observed line broadening, shift and/or splitting are assigned to an effect of the interface Ni-Pd (or Ni-Pt) layers. >

The magnetic multilayers consisting of ultrathin 3d‐transition metal and Pt or Pd layers are considered for the magneto‐optical storage media with increased information density. This paper reports on the magneto‐optical polar Kerr rotation and ellipticity spectra in Pt‐Ni multilayers at photon energies from 1.5 to 5.2 eV prepared by evaporation onto glass substrates. The thickness of individual Pt layers was kept constant at 2 nm in all samples studied while that of Ni layers varied between 0.9 and 3.9 nm. The prominent feature of the Kerr rotation spectra is a broad negative peak the amplitude of which increases with the individual Ni‐layer thickness. The multilayer spectra show less structure than that of pure Ni. Nevertheless the trends in multilayer spectra when the thickness of individual Ni layers changes can be reasonably simulated using the electromagnetic wave theory and permittivity spectra in bulk (or thick film) Ni and Pt.

In-depth profile changes induced by Ga+ ion irradiation in Pt(5 nm)/Co(3.3 nm)/Pt(20 nm)/Mo(20 nm) sandwiches MBE grown on Al2O3 substrates are deduced from complex magneto-optic polar Kerr effect (PMOKE) measurements at photon energies between 1 and 5 eV. The Ga+ irradiation stimulates a redistribution of Pt and Co and leads to broadening of alloyed regions at Pt-Co and Co-Pt interfaces, which is evaluated using PMOKE spectra. The effect of four Ga+ fluences D between zero and 6 × 1015 Ga+/cm2 was studied. The observed PMOKE azimuth rotation peak centered at 4.5 eV reaches the maximum of 0.42° at D = 1 × 1015 Ga+/cm2 and becomes thus enhanced by a factor of 3.2 with respect to that in the non-irradiated sample. At D = 6 × 1015 Ga+/cm2 the peak amplitude falls to 0.05°. To find the in-depth profile of Co concentration s in the sandwiches as a function of D, the PMOKE azimuth rotation and ellipticity spectra are compared with a multilayer model, where ideal flat interfaces are replaced by sequences of CosP...

International audience; This paper is devoted to magnetic and structural properties of anisotropicγ-Fe 2 O 3 γ-Fe2O3 superparamagnetic particles dispersed in a transparent xerogel matrix. The effect of frozen anisotropy axes and magnetic texture, induced by a magnetic field applied during the solidification of the matrix on the in-field magnetization process, is studied by alternating gradient force magnetometry and first and second order magneto-optical effects. The changes of magnetization curves with respect to the ferrofluid solution at the same particle concentration are interpreted on the basis of an existing statistical approach extended to systems with particle size distribution, which has to be taken into account for real samples. A very good agreement between the experiment and theory was achieved for a log-normal distribution of diameters which well resembles that deduced from electron microscopy observations in different imaging modes. This structural analysis states the parameter values used in calculations and confirms the relevance of basic assumptions of the model for the specimens studied. The experimental results and the related theoretical discussion should be of use to understand magnetic properties of other magnetically textured superparamagnetic systems.

Nous decrivons nos etudes magnetiques et magneto-optiques sur des multicouches Co-Ni/M (M = Pt, Au) preparees par evaporation sous ultra vide. L' anisotropie de surface K s augmente lineairement avec la teneur en Co ce qui verifie le modele a un ion. La teneur relative de Ni permet d'ajuster la temperature de Curie afin de pouvoir utiliser ces materiaux pour l'enregistrement thermomagnetique. La rotation Kerr presente un pic vers 4 eV pour les multicouches a base de Pt, qui se situe vers 2,5 eV pour celles d'or. On discute des resultats.

The authors consider magnetooptical spectroscopic studies of Pt/Co multilayers grown onto glass by dual electron beam evaporation an RF-sputtered Co rich Pt/sub x/Co/sub 1-x/ alloy films. Simultaneous polar and longitudinal magnetooptical Kerr experiments were carried out in the spectral range between 1.5 and 5.2 eV. The effect of the deposition temperature and that of subsequent heat treatment on the Kerr spectra is studied. In alloys Kerr rotation reached the value of 0.66 deg at 4.3 eV for x=0.41. >

The plane wave expansion method for calculating magneto-photonic crystals (MPCs) is modified via complex Fourier factorization whose basic principles are briefly explained. The new approach is used to simulate the photonic band structure of a two-dimensional MPC made as Bi:YIG rods arranged with square periodicity. The considerable improvement of the convergence properties is demonstrated for selected points of the bands.

The magneto-optical (MO) polar Kerr response of AlN/Fe/AlN/Cu/Si structures was optimized for a wavelength of 410 nm. Prior to the growth of the structures, the optimal thicknesses of the individual layers were determined by modelling to find the maximum MO figure of merit. Then the structures with different thicknesses of AlN layers were grown by sputtering. The optical properties of the AlN layers, grown by reactive sputtering, were characterized by ellipsometry. The MO polar Kerr spectroscopy was employed to measure the performance of the structures in the field of 3 kOe. The MO signal was scaled for saturation (factor 7) and saturation azimuth rotation greater than 20° was observed. The agreement between calculation and experimental data was remarkable, verifying the correct set of optical and MO parameters used in the model. These results provide a guide for the design of a MO sensor with optimal performance at a desired wavelength.

We report on optimizing the magneto-optical (MO) response of dielectric/Fe/dielectric sandwich structures for microwave B-field sensor applications. We have performed experimental MO spectroscopic and simulation studies of FeF2∕Fe∕FeF2 sandwiches with varying both top and bottom FeF2 layer thicknesses. We evaluate the performance of the sensor with MO figure of merit (off-diagonal reflection coefficient) rather than with MO polarization state (MO azimuth rotation and ellipticity). Our simulations indicate that an increase in the modulus of the MO signal by a factor of 17 is feasible compared to the bulk Fe. However, the corresponding enhancement of the figure of merit, which is the relevant parameter, is only threefold. These simulations were carried out for the operating wavelength of sensors at 810nm. We show, contrary to the general belief, that in order to enhance the MO performance of the sensor it is more important to optimize the bottom dielectric layer rather than the top layer.

Spectroscopic ellipsometry (SE) in the visible/near-UV spectral range is applied to monitor optical critical dimensions of quartz, Si, and Ta gratings, namely, the depth, linewidth, and period. To analyze the SE measurements, the rigorous coupled-wave theory is applied, whose implementation is described in detail, referred to as the Airy-like internal reflection series with the Fourier factorization rules taken into account. It is demonstrated that the Airy-like series implementation of the coupled-wave theory with the factorization rules provides fast convergence of both the simulated SE parameters and the extracted dimensions. The convergence properties are analyzed with respect to the maximum Fourier harmonics retained inside the periodic media and also with respect to the fineness of slicing imperfect Ta wires with paraboloidally curved edges.

Magneto-optical Kerr effect (MOKE) spectroscopy in the zeroth- and first-diffraction orders at polar magnetization is applied to Permalloy wire gratings deposited on Si substrates and protected by Cr capping. The experimental MOKE data are compared with data simulated using the local modes method. The extensive simulations of the MOKE spectroscopic parameters exhibit significant sensitivity to t(Cr2O3) and t(SiO2), the thicknesses of native oxide layers developed on the capping and the substrate, respectively. The approach may be useful for monitoring the basic micromagnetic properties of small elements with nanometer-scale resolution, as well as for monitoring the deposition processes and aging of magnetic nanostructures in magnetic recording and magnetic random access memory technologies.

Specular-mode spectroscopic ellipsometry is applied to analyze the optical response of gratings fabricated on a thick transparent plate substrate. The principles of the optical response of the gratings are described by employing incoherent contributions due to backreflections in the finite transparent substrate medium. A special function identifies a “diminution effect” caused by deflecting the secondary contributions from the primary beam axis. Two different methods are used to measure the ellipsometric response, a liquid solution method with the backreflections eliminated and a method including the incoherent backreflections. The grating parameters deduced by fitting from the measurement using the first method are applied to simulate the ellipsometric response using the second method. The spectral dependencies yielded by both methods are compared with remarkable agreement between the simulations and the measurements, which suggests the high usability of the backreflection method in the metrological char...

Magneto-optical Kerr effect (MOKE) spectroscopy in the -1st diffraction order with p-polarized incidence is applied to study arrays of submicron Permalloy wires at polar magnetization. A theoretical approach combining two methods, the local modes method neglecting the edge effects of wires and the rigorous coupled wave analysis, is derived to evaluate the diffraction losses due to irregularities of the wire edges. A new parameter describing the quality of the edges is defined according to their contribution in the diffracted MOKE. The quality factor, evaluated for two different samples, is successfully compared with irregularities visible on atomic force microscopy pictures.

Magneto-optical (MO) polar Kerr effect spectra in Ni Pt multilayers at 80 K show a strong increase in the spectra amplitudes, which exceeds that predicted by the model based on electromagnetic theory. An enhancement of the Kerr effect is observed at photon energies above 3 eV, similar to that in Co Pt and Fe Pt .

Polycrystalline Pt–Co multilayers with intentionally alloyed layers were grown by e-beam evaporation on polyimide, Si, and glass substrates. X-ray diffraction spectra show that the multilayered structure of the samples degrades as compared to conventional Pt–Co multilayers. This degradation depends on the compositional variation of the intentionally alloyed layers. Magnetometry measurements reveal enhanced magnetization values for all samples, exceeding even by 90% the one of bulk Co, at a temperature of 10 K. This is attributed to both Pt-induced and enhanced Co magnetic moments, according to x-ray magnetic circular dichroism experiments. Spectroscopic magneto-optic measurements reveal large negative polar Kerr rotation maxima at photon energies between 4 and 4.4 eV due to the intense magneto-optic response of spin-polarized Pt.

Magnetooptic (MO) effects in magnetic multilayers with periodically stratified regions are analyzed for the case of normal light wave incidence and polar magnetization (Faraday and polar Kerr effects). From the universal 4 x 4-matrix formalism simplified analytical representations restricted to terms linear in the off-diagonal permittivity tensor elements are obtained with no loss in accuracy. The MO effects are expressed as weighted sums of contributions from individual layers. Approximate expressions useful for the evaluation of trends in MO effects are given for periodic multilayers consisting of blocks with ultrathin magnetic films. The procedure is illustrated on periodic systems built of symmetric units. Limits on the ultrathin approximation are discussed.

The Yeh's 4 x 4 matrix formalism is applied to determine the electromagnetic wave response in multilayers with arbitrary magnetization. With restriction to magneto-optic (MO) effects linear in the off-diagonal permittivity tensor elements, a simplified characteristic matrix for a magnetic layer is obtained. For a magnetic film-substrate system analytical representations of the MO response expressed in terms of the Jones reflection matrix are provided. These are numerically evaluated for cases when the magnetization develops in three mutually perpendicular planes.