Magnetic shape-memory (MSM) alloys, such as NiMnGa, [1] reach maximum strains of close to 10% in single crystals. [2] This exceeds the strain obtainable from piezoelectric or magnetostrictive materials, currently used in actuators, by more than one order of magnitude, and opens new opportunities for applications. Advanced materials have been developed based on new compositions [3][4][5] or on innovative routes of fabrication resulting in foams, [6] fibers, [7] textured polycrystals, [8] or composites.[9] Thin MSM films with these high strains would be of significant benefit for use in microactuators. However, preparation of films exhibiting such high strains has not been achieved so far. In the present work, we demonstrate a new and enhanced thermal actuation mode, which is achieved by the use of freestanding, epitaxially grown NiMnGa films. This new mode utilizes a variant selection by magnetic stray-field energy within the martensite state. It allows for reversible actuation similar to the conventional two-way shape-memory effect, yet neither training nor an external magnetic field is required. A novel path to the realization of sub-micrometer, miniaturized microactuators based on MSM films is established. Due to the finite size of magnetic domains, this actuation mode is a unique feature of small systems.The novel mode uses both the ferromagnetic and martensitic properties of MSM alloys. Since it involves features of known actuation modes, these are described in the following. Shapememory alloys exhibit a diffusionless transition from a hightemperature cubic austenite phase to a low-temperature martensite phase of lower symmetry.[10] The martensitic phase may, as in the present case, exhibit a tetragonal structure with two identical long crystal a axes and one short c axis. Consequently, three different orientations of the martensitic c axis with respect to the cubic austenite cell are possible. Neighboring unit cells of identical orientation form so-called martensitic variants. Adjacent variants with different orientations are connected by twin boundaries. This special microstructure allows an easy deformation by changing the fractions of martensitic variants through twin-boundary motion. Heating to the cubic austenite state restores the original shape, which is the so-called one-way shape-memory effect. To obtain the two-way shape-memory effect, several cycles of mechanical training and heating are required. This presumably leads to the formation of microstructural defects, which can act as nucleation sites during martensite formation, memorizing the uneven variant distribution and hence the macroscopic shape.[11] For this actuation mode, temperature is the control parameter.Martensitic materials, which also exhibit ferromagnetic order, allow two additional actuation modes. The first type utilizes the coupling between crystal structure and spontaneous magnetization. In a magnetic field, the phase with the higher magnetic moment is energetically favored, leading to a field-dependent shift of the martensitic p...