Journal article
Nanoscale mechanical surface properties of single crystalline martensitic Ni-Mn-Ga ferromagnetic shape memory alloys
AM Jakob, M Müller, B Rauschenbach, SG Mayr
New Journal of Physics | IOP Publishing Ltd | Published : 2012
Abstract
Located beyond the resolution limit of nanoindentation, contact resonance atomic force microscopy (CR-AFM) is employed for nano-mechanical surface characterization of single crystalline 14M modulated martensitic Ni-Mn-Ga (NMG) thin films grown by magnetron sputter deposition on (001) MgO substrates. Comparing experimental indentation moduli-obtained with CR-AFM-with theoretical predictions based on density functional theory (DFT) indicates the central role of pseudo plasticity and inter-martensitic phase transitions. Spatially highly resolved mechanical imaging enables the visualization of twin boundaries and allows for the assessment of their impact on mechanical behavior at the nanoscale. ..
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Awarded by PtJ-Bio
Awarded by German Leibniz Association
Funding Acknowledgements
The authors are indebted to G Mahnke and Professor Dr M Seibt (Universitat Gottingen) for TEM measurements, Dr C Vree for initially stimulating the present work by setting up the group's first CR-AFM setup back in 2007 [10] and F Szillat (IOM/TRM Leipzig) for fruitful discussions. Resistivity measurements and subsequent analysis provided by F Schmidt and Professor Dr M Grundmann (Universitat Leipzig) are also acknowledged. We thank Dr S Vinzelberg (Atomic Force F&E GmbH, Germany) for support concerning AFM programming. This work was funded in part by the German Federal Ministry of Education and Research (BMBF), PtJ-Bio, 0315883, the Leipzig Graduate School of Natural Sciences BuildMoNa of the German Science Foundation (DFG) and the German Leibniz Association (SAW-2011-IOM-2).