"The understanding of magnetic coercivity is critical for understanding and enabling of the novel functionality in MSM alloys. One way how to control coercitivity is material doping. We studied the magnetic properties of Co, Cu, and B doped Ni-Mn-Ga materials but we did not find any effect of doping on the magnetic properties. Then we focused on the hypothesis that the coercivity is caused by so-called antiphase boundaries. These are boundaries on which structure order is changed. We developed a new method of visualization of antiphase boundaries by magnetic force microscopy. With a great help of this method we were able to detect the density of antiphase boundaries for various thermal treatment of the material. In the end we were able to achieve increased hysteresis by a thermal treatment. Importantly, in contrast by other methods, e.g. by introducing precipitates, we were able to maintain the ability of material to reorient in magnetic field. Thus we showed the way, how the novel functionality can be enabled.
For physical mechanisms underlying the novel functionalities, the understanding of the twinned microstructure of MSM alloys is critical. We studied the twinned microstructure of the material and made important findings. First of all we found a new type of twinning, so-called non-conventional twins, and also we identified the changes in microstructure during bending of the material. We also found nanotwinning in the material, which was not previously reported. All these findings are important for the reorientation in magnetic field and related both for the ordinary as well as for the novel functionality.
Related to application usage of the MSM materials we focused on the microscale applications since this is region where the novel functionalities are most likely to be used. We studied the possibilities of focused Xe-ion beam milling for preparation of MSM microdevices. We were able to create micropillars and developed a method of treatment of their surface, which resulted in functional micropillars. The micropillars were studied further and in the end we were able to demonstrate ultrafast actuation with micropillars.
All the above results were described in detail in international scientific publications. Results were also disseminated on the project webpage www.funmah.eu on the scientific conferences (ISPMA 15, Actuator 2018 and Esomat 18) and seminars and workshops (e.g. Ostre 2018). In addition the results on microdevices were displayed on the popular ""week of science"" events and we prepared one popular article on the MSM alloys, which is now under consideration for publication."
