We report on theoretical Kerr spectra of Fe/Pd multilayer systems as obtained on a first principl... more We report on theoretical Kerr spectra of Fe/Pd multilayer systems as obtained on a first principles basis by including multiple reflections and interferences at all the boundaries between the atomic layers. The complex optical conductivity tensor is calculated in terms of the Kubo equation by means of a contour integration technique such that finite temperatures and life-time broadening can be taken into account. In combination with the spin-polarized relativistic screened Korringa-Kohn-Rostoker band structure method, this technique provides the presently most sophisticated first principles computational approach of evaluating the complex optical conductivity tensor in layered systems without using the Kramers-Kronig relations, but accounting on the same footing for both the inter- and the intra-band contributions. In this contribution we analyze the Kerr effect in the Fe/Pd multilayer systems as a function of the number of Fe mono-layers and present a direct comparison to very recent experimental data.
ABSTRACT Using molecular dynamics, we simulate the abrasion process of an atomically rough Fe sur... more ABSTRACT Using molecular dynamics, we simulate the abrasion process of an atomically rough Fe surface with multiple hard abrasive particles. By quantifying the nanoscopic wear depth in a time-resolved fashion, we show that Barwell’s macroscopic wear law can be applied at the atomic scale. We find that in this multiasperity contact system, the Bowden-Tabor term, which describes the friction force as a function of the real nanoscopic contact area, can predict the kinetic friction even when wear is involved. From this the Derjaguin-Amontons-Coulomb friction law can be recovered, since we observe a linear dependence of the contact area on the applied load in accordance with Greenwood-Williamson contact mechanics.
The concept of the Bloch spectral function (BSF) has been extended to deal with disordered magnet... more The concept of the Bloch spectral function (BSF) has been extended to deal with disordered magnetic alloys with their electronic structure described using the spin polarized relativistic Korringa-Kohn-Rostoker Coherent Potential Approximation (SPR-KKR-CPA) formalism. Applications are presented for the alloy system fcc-FexNi1−x that shows a rather well defined dispersion relation and Fermi surface. Additional spin decomposition of the BSF clearly reveals the spin hybridisation due to spin-orbit coupling as well as its anisotropy in k-space.
The functionality of the lifting is exploited scheme to analyze several white light confocal imag... more The functionality of the lifting is exploited scheme to analyze several white light confocal images of tribological/ engineering surfaces in terms of their roughness, waviness and form. The roughness parameters obtained are then compared with those resulting from other standard filtering techniques, like Gaussian filtering. Based on the wavelet transform, an attempt will also be made to provide a robust parameter for surface characterization.
We report on theoretical Kerr spectra of Fe/Pd multilayer systems as obtained on a first principl... more We report on theoretical Kerr spectra of Fe/Pd multilayer systems as obtained on a first principles basis by including multiple reflections and interferences at all the boundaries between the atomic layers. The complex optical conductivity tensor is calculated in terms of the Kubo equation by means of a contour integration technique such that finite temperatures and life-time broadening can be taken into account. In combination with the spin-polarized relativistic screened Korringa-Kohn-Rostoker band structure method, this technique provides the presently most sophisticated first principles computational approach of evaluating the complex optical conductivity tensor in layered systems without using the Kramers-Kronig relations, but accounting on the same footing for both the inter- and the intra-band contributions. In this contribution we analyze the Kerr effect in the Fe/Pd multilayer systems as a function of the number of Fe mono-layers and present a direct comparison to very recent experimental data.
ABSTRACT Using molecular dynamics, we simulate the abrasion process of an atomically rough Fe sur... more ABSTRACT Using molecular dynamics, we simulate the abrasion process of an atomically rough Fe surface with multiple hard abrasive particles. By quantifying the nanoscopic wear depth in a time-resolved fashion, we show that Barwell’s macroscopic wear law can be applied at the atomic scale. We find that in this multiasperity contact system, the Bowden-Tabor term, which describes the friction force as a function of the real nanoscopic contact area, can predict the kinetic friction even when wear is involved. From this the Derjaguin-Amontons-Coulomb friction law can be recovered, since we observe a linear dependence of the contact area on the applied load in accordance with Greenwood-Williamson contact mechanics.
The concept of the Bloch spectral function (BSF) has been extended to deal with disordered magnet... more The concept of the Bloch spectral function (BSF) has been extended to deal with disordered magnetic alloys with their electronic structure described using the spin polarized relativistic Korringa-Kohn-Rostoker Coherent Potential Approximation (SPR-KKR-CPA) formalism. Applications are presented for the alloy system fcc-FexNi1−x that shows a rather well defined dispersion relation and Fermi surface. Additional spin decomposition of the BSF clearly reveals the spin hybridisation due to spin-orbit coupling as well as its anisotropy in k-space.
The functionality of the lifting is exploited scheme to analyze several white light confocal imag... more The functionality of the lifting is exploited scheme to analyze several white light confocal images of tribological/ engineering surfaces in terms of their roughness, waviness and form. The roughness parameters obtained are then compared with those resulting from other standard filtering techniques, like Gaussian filtering. Based on the wavelet transform, an attempt will also be made to provide a robust parameter for surface characterization.
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