To benefit from the latest technical improvements in atom probe analysis, a new tomographic atom probe has been built at the University of Münster, Germany. The instrument utilizes a femtosecond laser system with a high repetition rate combined with the ability of using a micrometer-sized extraction electrode and a wide angle configuration. Since field evaporation is triggered by laser pulses instead of high-voltage pulses, the instrument offers the ability to expand the range of analyzed materials to poorly conducting or insulating materials such as oxides, glasses, ceramics, and polymeric materials. The article describes the design of the instrument and presents characterizing measurements on metals, semiconductors, and oxide ceramic.

Interfaces of Ni/Cu multilayers were studied by atom probe tomography. To this aim, specimens with sharp or artificially smeared interfaces were prepared and investigated before and after annealing at 773 K. Owing to three-dimensional subnanometer resolution of the atom probe, local chemical analysis of layer interfaces becomes possible without interferences of grain boundaries or geometric roughness. In contrast to the classical expectation for a miscible system, but in agreement with more recent theoretical considerations, diffusion reduces the chemical width of the interfaces by up to 50%.

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Nanoscale systems show a wide variety of physical properties that cannot be observed in the bulk. Using atom probe tomography, it is possible to study nanostructured materials with almost atomic resolution in all three dimensions. In this article, we will present a short review of the latest atom-probe measurements carried out at University of Münster with particular focus on diffusion and segregation measurements in triple junctions and interface analysis.