The research and development in the field of magnetoresistive sensors has played an important role in the last few decades. Here, the authors give an introduction to the fundamentals of the anisotropic magnetoresistive (AMR) and the giant magnetoresistive (GMR) effect as well as an overview of various types of sensors in industrial applications. In addition, the authors present their recent work in this field, ranging from sensor systems fabricated on traditional substrate materials like silicon (Si), over new fabrication techniques for magnetoresistive sensors on flexible substrates for special applications, e.g., a flexible write head for component integrated data storage, micro-stamping of sensors on arbitrary surfaces or three dimensional sensing under extreme conditions (restricted mounting space in motor air gap, high temperatures during geothermal drilling).

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The production processes of the metalworking industry are usually carried out in the presence of oxygen. Par ticularly due to surface oxidation on tools and parts during production under normal atmosphere, high wear is observed in tribological systems. The focus of these investigations is the question to what extent the ambient atmosphere has an influence on the tribological system. For this purpose, the identification and characterization of wear mechanisms in an oxygen-free atmosphere is of high relevance. To analyse the influence of the ambi ent atmosphere on the tribological properties of titanium, ball-on-disc investigations are carried out on a univer sal tribometer (UMT) in an air, argon and silane-anodized atmosphere. By suppressing the oxidation under ex clusion of oxygen, a reduction of the tribochemical wear could be shown, which is accompanied by a reduction of the wear volume by a Factor of 4.5. However, due to the adhesion of both friction partners, which already occurs at low temperatures, caused by the omission of the friction-reducing cover layers, the friction coefficient increased. In addition, novel alloy formations at the interfaces were detected and analysed.

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New sensor and sensor manufacturing technologies are identified as a key factor for a successful digitalisation and are therefore economically important for manufacturers and industry. To address various requirements, a new sputter coating system has been invented at the Institute of Micro Production Technology. It enables the deposition of sensor systems directly onto technical surfaces. Compared to commercially available systems, it has no spatial limitations concerning the maximum coatable component size. Moreover, it enables a simultaneous structuring of deposited layers. Within this paper, characterisation techniques, results and challenges concerning directly deposited thin film strain gauges with the new sputter coating system are presented. Constantan (CuNiMn 54/45/1) and NiCr 80/20 are used as sensor materials. The initial resistance, temperature coefficient of resistance and gauge factor/k-factor of quarter-bridge strain gauges are characterised. The influence of a protective layer on sensor behaviour and layer adhesion is investigated as well. Moreover, the temperature compensation quality of directly deposited half-bridge strain gauges is evaluated, optimised with an external trimming technology and benchmarked against commercial strain gauges. Finally, the suitability for high-temperature strain measurement is investigated. Results show a maximum operation temperature of at least 400 °C, which is above the current state-of-the-art of commercial foil-based metal strain gauges.

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