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Smart Machining Processes
Published in E. S. Gevorkyan, M. Rucki, V. P. Nerubatskyi, W. Żurowski, Z. Siemiątkowski, D. Morozow, A. G. Kharatyan, Remanufacturing and Advanced Machining Processes for New Materials and Components, 2022
E. S. Gevorkyan, M. Rucki, V. P. Nerubatskyi, W. Żurowski, Z. Siemiątkowski, D. Morozow, A. G. Kharatyan
Among the most interesting functional nanomaterials, Fe–Pd ferromagnetic alloys are worthy of attention due to their excellent functional properties such as high uniaxial magnetic anisotropy, high Kerr rotation, magnetic shape memory effect, high corrosion resistance, and biocompatibility. Prida et al. (2012) underline that in addition to thin films, Fe–Pd nanowires and antidots are also promising smart materials suitable for magnetic shape memory nanoactuators, magnetocaloric or high-density data storage micro-devices.
A comparative study of the influence of the deposition technique (electrodeposition versus sputtering) on the properties of nanostructured Fe70Pd30 films
Published in Science and Technology of Advanced Materials, 2020
Matteo Cialone, Monica Fernandez-Barcia, Federica Celegato, Marco Coisson, Gabriele Barrera, Margitta Uhlemann, Annett Gebert, Jordi Sort, Eva Pellicer, Paola Rizzi, Paola Tiberto
Iron-palladium alloys arise great attention from the technological viewpoint as they show a unique and very interesting combination of mechanical and magnetic properties. As a result, they find uses in magnetic recording media [1–3], as microactuators and microsensors [4,5] or in spintronics [6]. In particular, the Fe70Pd30 (at.%) alloy shows the so-called ferromagnetic shape memory effect, related to the occurrence of a martensitic-to-austenitic phase transition [7,8]. This property is particularly appealing because, as compared to standard non-magnetic shape memory alloys, it allows for wireless magnetic manipulation. The possibility to induce the re-orientation of the twin boundaries in the martensite phase upon applying a magnetic field [9,10] makes it an excellent candidate for wirelessly actuated micro- and nanoelectromechanical systems (MEMS/NEMS) or strain sensors [11].
Numerical simulations on the high-frequency dynamic mechanical response of single-crystalline Ni–Mn–Ga samples
Published in Philosophical Magazine, 2022
Single-crystalline Ni–Mn–Ga alloys are one of the most known and widely studied magnetic shape memory alloys (MSMAs) [1,2]. Driven by external magnetic fields or mechanical loads, this group of materials can undergo significant and reversible strains (on the order of 6–10) [3–6]. At the microscopic level, the significant strain should be attributed to the martensite variant reorientation, which is realised through twin interface movements between the different variant regions. Compared with the conventional thermo-elastic SMAs, the response frequency of single-crystalline Ni–Mn–Ga alloys can reach 1–2 kHz [7]. These outstanding properties make Ni–Mn–Ga, the potential candidates for manufacturing novel sensors and actuators.
New insights into microstructural evolution of epitaxial Ni–Mn–Ga films on MgO (1 0 0) substrate by high-resolution X-ray diffraction and orientation imaging investigations
Published in Philosophical Magazine, 2018
Amit Sharma, Sangeneni Mohan, Satyam Suwas
Based on the literature available, the following microstructural parameters can affect the overall performance of Ni–Mn–Ga thin film-based shape memory devices:The magnetocrystalline anisotropy energy is strongly dependent on the orientation of the crystal with respect to the direction of applied field [44]. The facets formed on the surface have different orientations with respect to the matrix, and hence, the magnetic anisotropies are spatially distributed as opposed to the bulk. The difference in anisotropy energies can degrade the overall shape memory effect in the film.The other important microstructural parameter that affects the magnetic properties of thin films is surface roughness [45–47]. The formation of facets results in a significant increase in surface roughness in the film. It is reported for NiFe thin films that the anisotropy decreases and coercivity increases with an increase in surface roughness [48]. It is essential to understand the growth mechanism involved in the development of facets and their orientations to fabricate films with superior shape memory properties.The presence of defects and dislocations in the material acts as pinning site for the moment of domains in the presence of magnetic field [41,43]. The fabrication of films with reduced defect density is necessary to facilitate the magnetic shape memory effect.