Fundamental optical and magneto-optical constants of Co/Pt and CoNi/Pt multilayered films

A study has been made of the optical and magneto-optical properties of several Co/Pt and CoNi/Pt multilayered films that were fabricated by magnetron sputter deposition. Spectroscopic rotating analyzer ellipsometry and Kerr polarimetry were carried out to determine the fundamental optical and magneto-optical constants over the spectral range 320¿860 nm. The constants determined were the complex refractive index and the first-order magneto-optic Voigt parameter. A total of seven films were examined and excellent reproducibility was observed in the measured material constants. These have been used to discuss the spectral dependence of the figure-of-merit, for each material, associated with the detection of the polar Kerr effect

Magnetic, magneto-optic & microstructural properties of Co based multilayer films

SIGLEAvailable from British Library Document Supply Centre-DSC:DXN012012 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Recent advances in the study of biocorrosion: an overview Avanços recentes no estudo da biocorrosão: uma revisão

Biocorrosion processes at metal surfaces are associated with microorganisms, or the products of their metabolic activities including enzymes, exopolymers, organic and inorganic acids, as well as volatile compounds such as ammonia or hydrogen sulfide. These can affect cathodic and/or anodic reactions, thus altering electrochemistry at the biofilm/metal interface. Various mechanisms of biocorrosion, reflecting the variety of physiological activities carried out by different types of microorganisms, are identified and recent insights into these mechanisms reviewed. Many modern investigations have centered on the microbially-influenced corrosion of ferrous and copper alloys and particular microorganisms of interest have been the sulfate-reducing bacteria and metal (especially manganese)-depositing bacteria. The importance of microbial consortia and the role of extracellular polymeric substances in biocorrosion are emphasized. The contribution to the study of biocorrosion of modern analytical techniques, such as atomic force microscopy, Auger electron, X-ray photoelectron and Mössbauer spectroscopy, attenuated total reflectance Fourier transform infrared spectroscopy and microsensors, is discussed.<br>Processos de biocorrosão na superfície de metais são associados com microrganismos ou com os seus produtos metabólicos, tais como: enzimas, exopolímeros, ácidos orgânicos e inorgânicos, e compostos voláteis como amônio ou sulfeto de hidrogênio. Todos estes produtos podem afetar reações catódicas e/ou anódicas, alterando processos eletroquímicos na interface biofilme/metal. Esta revisão discute diversos mecanismos de biocorrosão causados pelos diferentes atividades fisiológicas associadas com microrganismos e os conhecimentos mais recentes. Estudos modernos da corrosão microbiologicamente influenciada focalizam problemas em ligas de ferro e de cobre. Microrganismos especialmente enfocados são as bactérias redutoras de sulfato e bactérias que depositam metais, destacando aquelas que depositam manganês. A importância de consórcios microbianos e o papel de substâncias poliméricas extracelulares na biocorrosão são enfatizados nesta revisão. Considera-se a contribuição de técnicas analíticas modernas, tais como microscopia de força atómica, espectroscopia Auger, espectroscopia de raio-X, espectroscopia Mössbauer, espectroscopia de infra-vermelho de reflectância total com transformação de Fourier e microsensores