Ferromagnetic shape memory alloys: synthesis, characterisation and biocompatibility of Fe–Pd for mechanical coupling to cells

Abstract

Yielding magnetically switchable strains of several percentage, ferromagnetic shape memory alloys (FSMAs) constitute a highly attractive materials class for engineering and biomedical applications. The Fe–Pd alloy is considered as a promising candidate to fulfil this goal, yet synthesis in the desirable martensite phase poses a major challenge, particularly when miniaturised as thin films. The present contribution reviews recent progress in synthesis via the splat-quenching and molecular beam epitaxy routes and reports on the physical picture that emerges from systematic characterisation. Moreover, since no cell damaging temperature variations are required to induce shape changes of FSMAs, Fe–Pd bears great potential for medical devices if good biocompatibility is ensured. Here we review studies on cellular response in contact with Fe–Pd, as well as morphological changes on roughness graded surfaces. We end with a summary how polymer coatings can enhance bioactive properties of Fe–Pd to promote cell adhesion and viability for future applications.