Satyakam Kar

1 Introduction Ni-Mn-based magnetic shape memory alloys are multiferroic materials and exhibit reversible ferroelastic and ferromagnetic transitions [1]. Coupling between both ferroic properties unlocks multifunctional effects in these materials, such as magnetic field-induced actuation [2], reaching a strain up to 12% [3], and actuation frequency up to 100 kHz [4], caloric effects for solid-state cooling [5, 6], and thermomagnetic harvesting of low-grade waste heat [7, 8].

1 Introduction Ferroic materials comprise ferromagnetic, ferroelectric, and ferroelastic materials, as well as combinations thereof, called multiferroics.[1, 2] While the influence of finite sample size on ferromagnetic properties already fills several textbooks, finite-size effects in ferroelectrics[3, 4] and multiferroics[5-7] are of current interest due to their high potential for miniaturized electronic devices.

Magnetic shape memory alloys are emerging multifunctional materials that enable applications like high-stroke actuation, solid-state refrigeration, and energy harvesting of waste heat. Thin films of these alloys promise integration in microsystems to exploit their multifunctional properties at the microscale. However, the microfabrication process of these Heusler alloys is difficult.