Concept of Damage Monitoring after Grinding for Components of Variable Hardness

AbstractThis paper deals with nondestructive magnetic evaluation of ground surfaces of chosen material hardness. The properties of prepared surfaces are studied with respect to the progressively worn grinding wheel. The nondestructive testing is based on the Barkhausen noise (BN) technique and obtained BN signals are supplemented by metallographic observations. The results show that the nature of thermal injury of the surfaces prepared by strongly worn grinding wheel significantly depends on the hardness of material. The typical thermal softening induced by grinding cycle is found on the surfaces of hardness 62 HRC whereas samples of lower hardness exhibit rehardening effect associated with the formation of white layer. These material changes are strongly correlated with the BN properties

Analytical expression of the magneto-optical Kerr effect and Brillouin light scattering intensity arising from dynamic magnetization

Time-resolved magneto-optical Kerr effect (MOKE) and Brillouin light scattering (BLS) spectroscopy are important techniques for the investigation of magnetization dynamics. Within this article, we calculate analytically the MOKE and BLS signals from prototypical spin-wave modes in the ferromagnetic layer. The reliability of the analytical expressions is confirmed by optically exact numerical calculations. Finally, we discuss the dependence of the MOKE and BLS signals on the ferromagnetic layer thickness

Optical Modeling of Microcrystalline Silicon Deposited by Plasma-Enhanced Chemical Vapor Deposition on Low-Cost Iron-Nickel Substrates for Photovoltaic Applications

AbstractThis paper deals with the optical modeling of thin hydrogenated microcrystalline silicon films grown on flexible low-cost iron-nickel alloy substrates by low-temperature (175°C) plasma-enhanced chemical vapor deposition. This material serves as the absorber in solar cells and hence it has direct impact on the resulting solar cell performance. Since the crystallinity and the material quality of hydrogenated microcrystalline silicon films evolve during the growth, the deposited film is inhomogeneous, with a rather complex structure. Real-time spectroscopic ellipsometry has been used to trace the changing composition of the films. In-situ ellipsometric data taken for photon energies from 2.8 to 4.5eV every 50seconds enabled us to study the evolution of the monocrystalline silicon fraction of the hydrogenated microcrystalline silicon films

Ordered thin films of magnetic nanoparticles

The investigation of physical properties of bulk materials is a traditional approach in materials science. During last decades the interest has been focused on two-dimensional ordered systems of nanometer-size particles with unusual mechanical, electrical, magnetic, optical, chemical properties, which are perspective for applications in electronics, optics, computer science and medicine. In this paper we report on the preparation of well ordered Langmuir-Blodgett films of g- Fe2O3 nanoparticles with an average size of 10nm. Arrangement and homogeneity were confirmed by scanning electron microscopy as well as atomic force microscopy. Magnetic properties were measured by the magneto-optical Kerr effect

Surface magnetic properties and domains observation in as-quenched and annealed FeNbB ribbons

The longitudinal magneto-optical Kerr effect (MOKE) combined with the magneto-optical microscopy is used to investigate the surface magnetic anisotropy and the domain behavior in as-quenched (AQ) and strain-annealed (SA) FeNbB ribbons. X-ray diffraction, conversion electron Mössbauer spectroscopy (CEMS), and scanning electron microscopy (SEM) confirmed the existence of approximately View the MathML source thick magnetically harder layer on the ribbon air side, consisting of crystallites embedded in an amorphous matrix. The underneath bulk phase is amorphous and magnetically soft. Residual anisotropies and the domain patterns (wide in-plane domains with 180ring operator walls and narrow fingerprint domains) corresponding to amorphous phase are mainly caused by the internal stresses originating from the rapid quenching process. In the surface crystalline phase they are gradually overlapped by strip domains with magnetization directions almost perpendicular to the ribbon axis. The anisotropy changes caused by additional annealing and straining of the samples are shown and discussed in detail

Spoof plasmons in corrugated semiconductors

We report on a theoretical investigation of the dispersion relation of surface plasmon polaritons (SPPs) on a periodically corrugated semiconductor surface. We assumed Drude’s permittivity model of the semiconductor, which accurately describes the loss of these spoof SPPs. In the THz frequency range, the properties of the dispersion and loss of spoof SPPs on corrugated Si surfaces are studied. A low-loss propagation of spoof SPPs can be achieved by an optimum design of the surface structure. It was found that by increasing the lattice constant or by reducing the groove depth, the investigated structure can provide a low guiding attenuation.Web of Science29141907189

Ellipsometric Selective Sensitivity to Magnetic Nanostructures

Recently, we have shown that the approach of depth sensitivity of magneto-optic ellipsometry can be generalized to selectivity from different materials in nanostructures. We use the condition number as the figure of merit to quantify the magneto-optic selectivity to two different magnetic contributions in magnetic nanostructure. The method is demonstrated on nanostructures containing magnetically hard Fe particles in surface layer of soft FeNbB amorphous ribbon. We separated both magnetic contributions from measurement of hysteresis loops using magneto-optic Kerr effect in longitudinal configuration. Magneto-optic selectivity is discussed and theoretical model on the basis of effective medium is compared with experimental data of longitudinal magneto-optic Kerr effect depending on angle of incidence

Ellipsometric selective sensitivity to magnetic nanostructures

Recently, we have shown that the approach of depth sensitivity of magneto-optic ellipsometry can be generalized to selectivity from different materials in nanostructures. We use the condition number as the figure of merit to quantify the magneto-optic selectivity to two different magnetic contributions in magnetic nanostructure. The method is demonstrated on nanostructures containing magnetically hard Fe particles in surface layer of soft FeNbB amorphous ribbon. We separated both magnetic contributions from measurement of hysteresis loops using magneto-optic Kerr effect in longitudinal configuration. Magneto-optic selectivity is discussed and theoretical model on the basis of effective medium is compared with experimental data of longitudinal magneto-optic Kerr effect depending on angle of incidence

Modeling of Mueller Matrix Response from Diffracting Structures

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