Resonant Raman characterisation of ultra-thin nano-protective carbon layers for magnetic storage devices

Carbon thin films are very important as protective coatings for a wide range of applications such as magnetic storage devices. The key parameter of interest is the sp3 fraction, since it controls the mechanical properties of the film. Visible Raman spectroscopy is a very popular technique to determine the carbon bonding. However, the visible Raman spectra mainly depend on the configuration and clustering of the sp2 sites. This can result in the Raman spectra of different samples looking similar albeit having a different structure. Thus, visible Raman alone cannot be used to derive the sp3 content. Here we monitor the carbon bonding by using a combined study of Raman spectra taken at two wavelengths (514 and 244 nm). We show how the G peak dispersion is a very useful parameter to investigate the carbon samples and we endorse it as a production-line characterisation tool. The dispersion is proportional to the degree of disorder, thus making it possible to distinguish between graphitic and diamond-like carbon. © 2003 Elsevier B.V. All rights reserved.

Designing for validation of medical devices and equipment

Validation is important in the design, development and production of medical devices since effective and appropriate validation plays a vital role in defining the success of a product in both technical and economic terms. Regulations and quality standards lay out the requirements for product validation, but it is left to each individual manufacturer to establish and maintain their own validation procedures. More recently, there has also been a change of emphasis in the regulations and standards that encourage the integration of validation into the development process. However, this poses particular challenges to the manufacturer since there is a distinct lack of guidance to assist this integration. This workbook provides the first real guidance on good design practices for medical device development. It has been developed through extensive consultation with device manufacturers and analysis of regulatory requirements. The approach is intended to assist manufacturers in meeting the new regulations.