oa Editorial [Hot Topic: Recent Applications of In-Situ Mechanical Characterisation on Micro- & Nano-systems (Guest Editor: Kalin Dragnevski)]

Over the past few decades mechanical characterisation of material systems has become a well-established and in many cases routine experimental procedure and when used in combination with microscopy (e.g. Electron or Atomic) allows not only the evaluation of the mechanical properties (e.g. tensile strength) of the studied system, but also the in-situ examination of the microstructural and fracture development of the material in question and in the case of AFM the adhesive properties of the system. Another way of examining the mechanical response (e.g. acoustic velocity, related to Young’s modulus) of a system of interest in-situ is by directly measuring its properties on the device that it is designed to be part of (e.g. acoustic filter). However, as the scale of the experiments and studied systems decreases and their complexity increases, it becomes absolutely necessary to design and engineer not only different types of novel materials and specimen geometries, but also novel devices and fixtures that would accommodate the intended measurements. The principal aim of this special issue is to give an overview of the latest research and developments in specific areas of micro- and nano-scale characterisation. The topics covered in the contributing papers address the most recent trends in in-situ mechanical characterisation of micro- and nano-systems; examples include classic metals (e.g. Ni) advanced thermal barrier coatings (TBC), thin film bulk acoustic resonators (FBAR) & bacterial cells (e.g. E.coli). The paper by Maitland et al., presents the results from a study aimed at the development of a methodology for examining stable crack growth in thermal barrier coatings at high resolutions. The contribution by Craig et al., which is also based on the development of a Microscopical technique (AFM), presents the results from a pilot study where novel thermal probes were used in an attempt to characterise their interactions with biological systems. In contrast, the paper by Nirschl et al., deals with the other aspect of in-situ materials characterisation described above. In their paper the authors clearly demonstrate how FBAR can be a used as a tool to characterise the mechanical properties of thin films in-situ on a micro- and nanoscale within a certain range of parameters. The contribution by Korsunsky et al., reviews some recently developed diffraction techniques, based on the use of (sub)microscopic focused X-ray beams and aimed at the characterisation of material structure and mechanical behaviour at unprecedented spatial resolution. Overall, it is strongly believed that the articles in this special issue present original experimental research and that these will be of interest to the readers of Micro & Nanosystems and scientists in the more general fields of Engineering and Materials Science.